)
...Thats so bad...
import java.io.*;
public class FileOps {
public static void main(String args[])
{
File file = new File(args[0]);
try
{
BufferedReader in = new BufferedReader(new FileReader(file));
String s;
s = in.readLine();
while(s!=null)
{
System.out.println("Read " + s);
s = in.readLine();
}
in.close();
}
catch(FileNotFoundException e1)
{
System.err.println("File Not Found" + file);
}
catch(IOException e2)
{
e2.printStackTrace();
}
}
}Just a small note. The file need not exist in the same directory from which the program is executed. In that case, the complete path (absolute path) of the files should be specified.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class sudoku1 extends Frame implements ActionListener,KeyListener {
int i,j;
int x,y;
Button b;
Graphics g;
sudoku1(String s)
{
super(s);
setTitle("Sudoku");
setSize(1000,700);
addKeyListener(this);
b=new Button("New Game");
setLayout(new BorderLayout());
b.addActionListener(this);
add(b,BorderLayout.SOUTH);
addWindowListener(new WindowAdapter(){public void windowClosing(WindowEvent e){System.exit(0);}});
setVisible(true);
g=getGraphics();
}
/*public void control(KeyEvent e)
{
if(e.getKeyCode()==VK_ENTER)
JOptionPane.showMessageDialog(null,"right");
}*/
public void keyPressed(KeyEvent e)
{
if(e.getKeyCode()==VK_RIGHT)
JOptionPane.showMessageDialog(null,"right");
}
public void keyReleased(KeyEvent e){}
public void keyTyped(KeyEvent e){}
public void draw()
{
g.setColor(Color.BLUE);
x=500;
y=350;
i=j=0;
while(i<10) //platform of the game is printed on screen.
{
g.drawLine(x-270+60*i,y-270,x-270+60*i,y+270);
g.drawLine(x-270,y-270+60*i,x+270,y-270+60*i);
if(i==3||i==6)
{
g.drawLine(x-270+60*i+2,y-270,x-270+60*i+2,y+270);
g.drawLine(x-270,y-270+60*i+2,x+270,y-270+60*i+2);
}
i++;
}
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==b)
draw();
}
public static void main(String[] args) {
// TODO code application logic here
sudoku1 m=new sudoku1("Sudoku");
}
}if(e.getKeyCode()==KeyEvent.VK_RIGHT)
NetBeans - The only IDE you need !
Oh yeah...i forgot that geany is not only for C/C++ but for java too, thanks for reminding me
Its good for large scale projects, else i am better off with Eclipse or geany
for(int i = 0; i < 4; i++, System.out.println())
for(int j = 0; j <= i; j++)
System.out.print("*");for(int i = 0; i < 4; i++, System.out.println())
{
for(int j = 4; j > i; j--)
System.out.print(" ");
for(int k = 0; k <= i; k++)
System.out.print("*");
}I kinda disappointed Aniruddh the last time with his Electronic showroom thing, and he's really at a very early stage of learning, so I thought it might help him better this way than exchaning multitude of PM's and emails for a trivial thing as this.He just ask the logic, but u provide him the code....
*i38.tinypic.com/33l2q81.jpg
EntityManagerFactory factory = Persistence.createEntityManagerFactory("acme");
EntityManager entityManager = factory.createEntityManager();
...
entityManager.close();package com.ocricket.entity;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;
import org.apache.log4j.Logger;
/**
*
*/
public class EntityManagerUtil {
private static final EntityManagerFactory emf;
private static final ThreadLocal<EntityManager> threadLocal;
Logger log = Logger.getLogger(EntityManagerUtil.class);
static {
emf = Persistence.createEntityManagerFactory("OCRICKETPU");
threadLocal = new ThreadLocal<EntityManager>();
}
public static EntityManager getEntityManager() {
EntityManager manager = threadLocal.get();
if (manager == null || !manager.isOpen()) {
manager = emf.createEntityManager();
threadLocal.set(manager);
}
return manager;
}
public static void closeEntityManager() {
EntityManager em = threadLocal.get();
threadLocal.set(null);
if (em != null) em.close();
}
public static void beginTransaction() {
getEntityManager().getTransaction().begin();
}
public static void commit() {
getEntityManager().getTransaction().commit();
}
public static void rollback() {
getEntityManager().getTransaction().rollback();
}
public static Query createQuery(String query) {
return getEntityManager().createQuery(query);
}
}<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="*java.sun.com/xml/ns/persistence"
xmlns:xsi="*www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="*java.sun.com/xml/ns/persistence
*java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
version="1.0">
<persistence-unit name="OCRICKETPU"
transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<properties>
<property name="hibernate.connection.driver_class"
value="org.postgresql.Driver" />
<property name="hibernate.connection.url"
value="jdbc:postgresql://localhost:5432/ocricket" />
<property name="hibernate.connection.username"
value="postgres" />
<property name="hibernate.connection.password"
value="000000" />
<property name="databasePlatform"
value="org.hibernate.dialect.PostgreSQLDialect" />
<property name="hibernate.use_sql_comments" value="true" />
<property name="hibernate.hbm2ddl.auto" value="create" />
</properties>
</persistence-unit>
</persistence>
Going through the TLD docs and Java docs of the class and Tag I provided you should clarify everything for you.
Splashscreen-Image: <image_path_relative_to_JAR>
.) and eclipse is open source.. so most of corporates are using eclipse.
If all references are well scoped and proper OO principles are followed, there is no need to worry about memory management (both stack and heap). If you still feel there can be need to worrying about memory, pls give me a sample program scenarios following proper OOP principles, which can lead to OutOfMemoryError.no mate... for memoery u have to be carful..i mean..u should take care of things which can cause leaks and heap explodes
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.DecimalFormat;
import com.sun.j3d.utils.timer.J3DTimer;
*java.sun.com/javase/6/docs/api/
*in.youtube.com/comment_servlet?all_comments&v=GvctSMHHd7g&ytsession=p9A_Dz6f8kXK5uX7c4IxRXCHB9HQut1nIGY5pSuqgGeeKrFz1pYtma0JOAMlINEJELSf9R85VAbMqGZhLjBDGw-Jg8LGV1e2C3ZTLwiHnz5f7eHpk5aIrfFVkmJksyn4pw4ur6twt4OoW7N8aRmBD58Ft-kefWBBDA3BsU4PJ7IrnfR5Jd-HXVRcOI_fnGg1GAXU8k0OCbr-I024_h6l0AL3TaaGGAFdED_egjgErjDuWe3e_-R89fqmuZ8a8-hn-wnsNIl-O5BqZT26bLzr1wCK2f4V76Z_dO7xfKe7BQQpackage demo;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
@Retention(RetentionPolicy.RUNTIME)
public @interface Permission {
String name();
}package demo;
public class Main {
public static void main(String[] args) {
Demo demo = new Demo();
Permission permission = demo.getClass().getAnnotation(Permission.class);
System.out.println(permission.name());
}
}
@Permission(name = "ADMIN")
class Demo {
}/**
* User Model
**/
public class User {
private String username;
private String password;
private int age;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}/**
* Action
**/
public class Login extends ActionSupport implements ModelDriven<User>{
private User user;
public User getModel() {
return user;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
// Acton
public String login (){
return "outcome";
}
}<package name="user" extends="struts-default">
<action name="login"
class="com.desitek.cricket.action.Login">
<result name="input">index.jsp</result>
<result name="success">index.jsp</result>
<result>index.jsp</result>
</action>
</package> <s:actionerror/> <s:actionmessage/>
<s:fielderror></s:fielderror>
<s:form action="login" theme="simple">
User Name
<s:textfield name="user.Username"></s:textfield>
Password: <s:textfield name="user.UserPassword"></s:textfield>
<s:submit value="login"></s:submit>
</s:form>public class LoginAction {
private User user;
public User getModel() {
return user;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public String login (){
return "outcome";
}
}<managed-bean>
<managed-bean-name>login</managed-bean-name>
<managed-bean-class>com.desitek.cricket.action.LoginAction</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
</managed-bean>
<navigation-rule>
<from-view-id>login.jsp</from-view-id>
<navigation-case>
<from-outcome>success</from-outcome>
<to-view-id>index.jsp</to-view-id>
</navigation-case>
<navigation-case>
<from-outcome>failure</from-outcome>
<to-view-id>login.jsp</to-view-id>
</navigation-case>
</navigation-rule>javax.servlet.ServletException: /login.jsp(35,2) '#{user.user.username}' Target Unreachable, 'user' returned null
javax.faces.webapp.FacesServlet.service(FacesServlet.java:256)
[B]root cause[/B]
org.apache.jasper.el.JspPropertyNotFoundException: /login.jsp(35,2) '#{user.user.username}' Target Unreachable, 'user' returned null
org.apache.jasper.el.JspValueExpression.getType(JspValueExpression.java:61)
com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getConvertedValue(HtmlBasicInputRenderer.java:81)
javax.faces.component.UIInput.getConvertedValue(UIInput.java:934)
javax.faces.component.UIInput.validate(UIInput.java:860)
javax.faces.component.UIInput.executeValidate(UIInput.java:1065)
javax.faces.component.UIInput.processValidators(UIInput.java:666)
javax.faces.component.UIForm.processValidators(UIForm.java:229)
javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1030)
javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:662)
com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:100)
com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:117)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:244)package com.desitek.cricket.action;
/**
* Action
**/
public class User {
private String username;
private String password;
private String email;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}package com.desitek.cricket.action;
public class LoginAction {
private User user;
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public String login() {
System.out.println(user.getUsername());
return "success";
}
}<f:view>
This is my JSF JSP page. <br>
<h:form>
Username
<h:inputText value="#{user.user.username}"></h:inputText>
Password
<h:inputText value="#{user.user.password}"></h:inputText>
<h:commandButton action="#{user.login}" value="submit" ></h:commandButton>
</h:form>
</f:view><managed-bean>
<managed-bean-name>user</managed-bean-name>
<managed-bean-class>com.desitek.cricket.action.LoginAction</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
</managed-bean>
<navigation-rule>
<from-view-id>login.jsp</from-view-id>
<navigation-case>
<from-outcome>success</from-outcome>
<to-view-id>index.jsp</to-view-id>
</navigation-case>
<navigation-case>
<from-outcome>failure</from-outcome>
<to-view-id>login.jsp</to-view-id>
</navigation-case>
</navigation-rule> package com.desitek.cricket.action;
public class LoginAction {
private User user = new User();
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public String login() {
System.out.println(user.getUsername());
return "success";
}
} class A { some code}
class B {some code A a = new A}
class C{
p s v main
{some code}
}
An object can be created anywhere, anytime from a class as long as its scope allows it to be. Have you not learnt OO concepts at school yet?Thanx for the screenshots, cleared the doubt like Harpic cleans the $hit from the flush.
In the first example u've created the object of A in constructor of B. Is it the only way or it can be done another way also?
In the first example u've created the object of A in constructor of B. Is it the only way or it can be done another way also?
OK, this is really n00bish compared to your standards, but still:
can anyone explain the "while","do while" functions (ie.loop) with an example? e-books arent helping here
[COLOR=SeaGreen][B]while(i < 2)[/B][/COLOR]
{
...
}
System.out.println("\nTesting the exit controlled loop\n");
int j = 0;
do
{
...
} [COLOR=Red][B]while (j == 100);[/B][/COLOR]
}
}Thanks man. Really great explanation (although it took some time to understand use of words such as "boolean" etc. as they are not used commonly [I know what boolean means
] )
I never meant to undermine your reply.
Chill never mind. Let's stick to our cup of Java.
No, its just that the doubt was too trivial. Why would I wanna doubt your programming knowledge? :\
Classes for it will begin early next year so till then I've to get good in my Core JAVA. That I'll do by myself and with ur help and support but for J2ME, they'll give books too but can u guys recommend some good ones which are of Engineering student's level, not n00bish like NIIT's?
thats dependent on server not javai need some basic concept how to implement https in java...do u have any reference/tutorial/links...i wanna understand it...
no code please...!!!
Because those are the languages whose shortcomings, Java was meant to solve. Today C/C++ and Java rule entirely different territories.But wonder why they are so much against C/C++
I have never read that book. Can you post the code for us to view?as anyone learning to code first time should skip this. don't believe me check out the first HelloWorld programs given in chapter 1
public Welcome {
public static void main(String args[]) {
String[] greeting = new String[3];
greeting[0] = "Welcome to Core Java";
greeting[1] = "by Cay Horstmann";
greeting[3] = "and Gary Cornell";
for(int i = 0; i < greeting.length; i++)
System.out.println(greeting[i]);
}
}Please check whether you typed in properly. I really don't think it would be this crappy.
Boss, i was typing it.Please check whether you typed in properly. I really don't think it would be this crappy.
Submitted while typing??Boss, i was typing it.
I guess you are too fast
yaar, i was clicking on preview post button.Submitted while typing??
Anyway just kidding carry on.
Note: You missed "class" in the first line.
ren file.??? file.???.rarpackage demo;
import java.io.File;
public class Main {
public static void main(String[] args) {
File directory = new File("/home/chandru/temp");
for (int i = 1; i <= 2; i++) {
String numberString = String.format("%03d", i);
File originalFile = new File(directory, "file." + numberString);
File targetFile = new File(directory, "file" + numberString
+ ".rar");
originalFile.renameTo(targetFile);
}
System.out.println("Rename complete.");
}
}
) (and I already Fwd it )
Otherwise will have to issue a RPC via RMI to stop it all
Java Micro Edition - Smallest and meant for devices with limited processing power.
Oh yeah, I had left out Java card. It is the smallest Java platform. Even smaller than Java ME.
Why don't you try a search engine for this?
JSP and Servlet can definitely handle multi-part request. But the catch is that writing code for parsing and using multi-part requests is tedious that it is better to get the job done with a library. Commons FileUpload is one such API. Commons FileUpload as a dependency needs Commons IO. Once you have both in your web-app's classpath, here is a sample code for uploading files using Commons FileUpload.
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"*www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Upload Page</title>
</head>
<body>
<form action="UploadServlet" method="post" enctype="multipart/form-data">
User Name:
<input name="username" type="text" />
<br>
File to Upload: <input name="uploadFile" type="file"/>
<br>
<input type="submit" value="Submit" />
</form>
</body>
</html>package demo;
public class UploadServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/plain");
PrintWriter out = response.getWriter();
try {
FileItemFactory factory = new DiskFileItemFactory();
FileUpload upload = new FileUpload(factory);
List<FileItem> items = upload.parseRequest(new ServletRequestContext(request));
for (FileItem item : items)
if (item.isFormField())
System.out.println(item.getFieldName() + " " + item.getString());
else {
File uploadedFile = new File("/home/chandru/demo.png");
item.write(uploadedFile);
}
RequestDispatcher dispatcher = request.getRequestDispatcher("result.jsp");
dispatcher.forward(request, response);
} catch (Exception e) {
e.printStackTrace();
} finally {
out.close();
}
}
}An outer class cannot be declared static. Inner classes can be. Here, B is an inner class.
for(int i=0;i<10;i++)
for(int j=0;j<10;j++)
{
xyz[i] = new B();
xyz[i].abc[j]=temp;
}Thanks Bandu,
There is no way they can be reported to be equal. Are you sure?
)
Could someone explain the loop structure in an array? (both single and double dimensional)
Even link would do (or a page no./chapter no. on Shildt's Java Reference book
int x[][]=new int[4][4];
for(int i: x[]) {
for(int j :x) {
------
------
}
}How can a while loop not have a body? I couldnt get that.
Agreed
Could someone explain this line to me?
How can a while loop not have a body? I couldnt get that.
//infinite for loop
for( ; ; );Well actually "nothing" is executed for each iteration of the loop...
Visit following Links:
");");I need to make only certain texts within a cell to be bold
remove multiple path variables to jdks and update the only path variable to newer jdk 1.6 update version
import javax.swing.JFrame;
import javax.swing.ImageIcon;
import java.awt.Image;
public class Test
{
public static void main(String[] args) throws Exception
{
Test tt = new Test();
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
try
{
frame.setIconImage(java.awt.Toolkit.getDefaultToolkit().getImage(tt.getClass().getResource("icon-mercedes.png")));
}
catch(Exception e)
{
e.printStackTrace();
}
frame.pack();
frame.setVisible(true);
}
}ya same question from me too
I face a lot of issues while i m running java when i started to learn it... And i think the same issues will still alive.. If anyone find such kinda issue then please post it here instead of creating a new thread..
Yes this thread is dedicatedto Java(if u like J2EE toooo....
So please drop ur queries here...
I want the Javascript code to shutdown the system. Can anybody gimme?
Check this
i want to learn java script. so u can give better java e books on my id.and give me advise for learn java.
*livedocs.adobe.com/director/mx2004...X_2004_Documentation&file=07_me412.htm#191023
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
class swingdemo extends Frame implements ActionListener
{
JFrame frm;
JMenuBar mb;
JMenu mFile,mTransaction;
JMenuItem itmLogin,itmQuitApp,itmCashDeposit,itmChequeDeposit;
JLabel lblName;
JTextField txtName;
public swingdemo()
{
frm = new JFrame("Bank Management System");
frm.setLayout(null);
frm.setSize(600,500);
frm.setVisible(true);
//Menu Coding
mb = new JMenuBar();
mFile = new JMenu("File");
itmLogin = new JMenuItem("Login");
itmQuitApp = new JMenuItem("Quit Application");
mFile.add(itmLogin);
mFile.add(itmQuitApp);
mTransaction = new JMenu("Transaction");
itmCashDeposit = new JMenuItem("Cash Deposit");
itmChequeDeposit = new JMenuItem("Cheque Deposit");
mTransaction.add(itmCashDeposit);
mTransaction.add(itmChequeDeposit);
itmCashDeposit.addActionListener(this);
mb.add(mFile);
mb.add(mTransaction);
frm.setJMenuBar(mb);
//Label
lblName = new JLabel("Name");
lblName.setBounds(70,20,200,50);
frm.add(lblName);
txtName = new JTextField(25);
txtName.setBounds(140,20,150,20);
frm.add(txtName);
}
public void actionPerformed(ActionEvent e)
{
Object o = e.getSource();
if(o==itmCashDeposit)
{
}
}
public static void main(String args[])
{
swingdemo s = new swingdemo();
}
}import javax.swing.*;
class SimpleFrame extends JFrame
{
public SimpleFrame()
{
this.setSize(200,200);
this.setLocation(200,200);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void showIt()
{
this.setVisible(true);
}
public void showIt(String title)
{
this.setTitle(title);
this.setVisible(true);
}
public void showIt(String title,int x,int y)
{
this.setTitle(title);
this.setLocation(x,y);
this.setVisible(true);
}
public static void main(String args[])
{
SimpleFrame f = new SimpleFrame();
f.showIt();
}
}
gopi_vbboy said:
create a new func and call it from main,then it will solve.Check this code out:
Now I'm getting this error "Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0Code:import java.io.*; public class FileOps { public static void main(String args[]) { File file = new File(args[0]); try { BufferedReader in = new BufferedReader(new FileReader(file)); String s; s = in.readLine(); while(s!=null) { System.out.println("Read " + s); s = in.readLine(); } in.close(); } catch(FileNotFoundException e1) { System.err.println("File Not Found" + file); } catch(IOException e2) { e2.printStackTrace(); } } }
at FileOps.main(FileOps.java:13)
Java Result: 1
"
What's the solution?
<html>
<head>
<script type="text/javascript">
function timedText(){
var i=1000;
for(i=1000;i<=20000;i=i+1000){
setTimeout("document.getElementById('txt').value="+i,i);
}
}
</script>
</head>
<body>
<form>
<input type="button" value="Display timed text!" onClick="timedText()">
<input type="text" id="txt">
</form>
<p>Click on the button above. The input field will tell you when two, four, and six seconds have passed.</p>
</body>
</html>
set PATH = %PATH%;"C:\Program Files\Java\jdk1.6.0_20\bin"set PATH = %PATH%;"C:\Program Files\Java\jdk1.6.0_20\bin"echo %PATH%set PATH = %PATH%;"C:\Program Files\Java\jdk1.6.0_20\bin"[B];.[/B]class HelloWorldApp{
public static void main(String[] arg) {
System.out.println("Hello World");
}
}
. dont know recursive algorithm.
actually liverpool fan i am just a beginner.
int i = 1;
i = i + 1.2;int i = 1;
i += 1.2;int i = 1;
i = i + (int)1.2;int i = 1;
i = (int)((float)i + 1.2);
Can you please elaborate on this? I think I didn't get you. What do you mean by not implicit?
The one for 358. Might be a mistake at their side. If it costs 2000 bucks, i'd rather add 2500 and get HD5670....
anyways I'll be needing one book for computer networks also
I've a vague idea about it, but the book should cover all relevant topics which comes in computer networks
The one for 358. Might be a mistake at their side. If it costs 2000 bucks, i'd rather add 2500 and get HD5670....
[CODE]class NewThread implements Runnable{
Thread t;
NewThread(){
t=new Thread(this,"Demo Thread");
System.out.println("Child Thread: " + t);
t.start();
}
public void run(){
try{
for(int i=5;i>0;i--){
System.out.println("Child Thread: " + i);
Thread.sleep(500);
}
}catch(InterruptedException e){
System.out.println("Child interrupted.");
}
System.out.println("Exiting child thread.");
}
}
class ThreadDemo {
public static void main(String args[]){
new NewThread();
try{
for(int i=5;i>0;i--){
System.out.println("Main Thread: " + i);
Thread.sleep(1000);
}
}catch(InterruptedException e){
System.out.println("Main thread interruoted.");
}
System.out.println("Main thread exiting.");
}
}
anyways I'll be needing one book for computer networks also
I've a vague idea about it, but the book should cover all relevant topics which comes in computer networks
String r = s.charAt(s.length()-1) + s.substring(0, s.length()-1);Though both are good, you can choose any but eclipse has better user interface and easy to use!
Thanks for the links, but I have been working on Netbeans, so can you please provide the same info for Netbeans...
dog[] pets;
pets= new dog[7];dog[] pets=new dog[7];dog d1=new dog();dog[] d=new dog[7];
dog[0]=new dog();
dog[1]=new dog();
//...and so ondog[] d=new dog[7];
dog[0]=new dog();
dog[1]=new dog();
//...and so ondog[] d=new dog[7];
[B]d[0][/B]=new dog();
[B]d[1][/B]=new dog();
//...and so ond1.bark();d[0].bark();[B]class animal[/B]
{
eat();
sleep();
noise();
}
[B]class dog extends animal[/B]
{
eat()
{
//statements
}
noise()
{
//statements
}
}
[B]class lion extends animal[/B]
{
eat()
{
//statements
}
noise()
{
//statements
}
}
[B]class hippo extends animal[/B]
{
eat()
{
//statements
}
noise()
{
//statements
}
}
[B]class vet(animal a)[/B]
{
cure()
{
//statements
}
}
[B]class wildlife[/B]
{
public static void main(String[] args)
{
dog d=new dog();
lion l=new lion();
hippo h=new hippo;
vet v=new vet();
[COLOR="Red"]//what is happening after this line?[/COLOR]
v.cure(d);
v.cure(h);
}
}
Only if you don't have a computer.
class testing
{
public static int testprime(int num)
{
int flag=0;
for(int i=1;i<=num;i++)
{
if(num%i==0)
{
flag++;
}
}
if(flag>2)
return 0;
else
return 1;
}
public static void main(String args[])
{
int i,n=0,flag=0,t,x;
int p=2;
while(n<=10001)
{
x=n;
t=testprime(p);
if(t==1)
{
p++;
n++;
}
else
{
p++;
n=x;
}
}
}
}import java.io.*;
class puzzle
{
int a[][]={{8,2,7,4},{1,11,0,10},{15,3,12,5},{14,6,13,9}};
int n; int r=0; int c=0;
public void main()throws IOException
{
display();
do
{
input();
swapping(a, r, c);
checkForCompletion();
display();
}while(true);
}
public void input()throws IOException
{
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter the number to move");
System.out.println("Enter 0 to exit");
n=Integer.parseInt(br.readLine());
int flag=0;
int c=0,r=0;
for (int i=0;i<4;i++)
for(int j=0;j<4;j++)
{
if(n==a[i][j])
{
r=i;
c=j;
flag=1;
break;
}
}
if(n<1&&n>15)
System.out.println("Invalid Input");
else if (flag!=1)
System.out.println("Invalid Input");
else if(n==0)
System.exit(0);
}
public void swapping(int a[][], int r, int c)
{
int fl=0;
for (int i=0;i<4;i++)
for(int j=0;j<4;j++)
{
if(r!=3||a[r+1][c]==0)
{
a[r+1][c]=n;fl=1;
a[r][c]=0;
}
else if(r!=0||a[r-1][c]==0)
{
a[r-1][c]=n;fl=1;
a[r][c]=0;
}
else if(r!=0||a[r][c-1]==0)
{
a[r][c-1]=n;fl=1;
a[r][c]=0;
}
else if(r!=3||a[r][c+1]==0)
{
a[r][c+1]=n;fl=1;
a[r][c]=0;
}
}
if(fl!=1)
System.out.println("Cannot be moved");
}
public void checkForCompletion()
{
int c=1;int fl=0;
for (int i=0;i<4;i++)
for(int j=0;j<4;j++)
{
if(i!=4&&j!=4)
{
if(a[i][j]!=c++)
fl=1;
}
}
if (fl==0)
{
System.out.println("Completed");
System.exit(0);
}
}
public void display()
{
for (int i=0;i<4;i++)
{
for(int j=0;j<4;j++)
{
System.out.print(a[i][j]+" ");
}
System.out.println();
}
}
}import java.io.*;
/**
* A puzzle game
* @author Shirish Padalkar
*
*/
public class Puzzle {
/**
* Reader to read numbers from standard input
*/
static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
/**
* Main method which handles the puzzle. The flow of the puzzle is as following:
* <ol>
* <li>Display the current state of puzzle</li>
* <li>If puzzle is not completed, ask for a number to move.</li>
* <li>Check if the number is in valid input range.</li>
* <li>Check if the number can be moved. If yes, then move the number, else show error message. Go to step 2.</li>
* <li>Move the number.</li>
* <li>Go to step 1</li>
* </ol>
* @param args command line arguments
*/
public static void main(String[] args) {
/**
* Array to hold the numbers of the puzzle.
*/
int[][] array = {
{ 8, 2, 7, 4 },
{ 1, 11, 0, 10 },
{ 15, 3, 12, 5 },
{ 14, 6, 13, 9 }
};
/*int[][] array = {
{ 1, 2, 3, 4 },
{ 5, 6, 7, 8 },
{ 9, 10, 11, 12 },
{ 13, 14, 0, 15 }
};*/
boolean completed = false, validInput = false;
int number;
System.out.println("Welcome to Puzzle. Please enter 0 to exit.");
display(array);
while (!completed){
number = input();
if (number == 0){
System.exit(0);
}
validInput = isValidInput(array, number);
if (!validInput){
System.err.println("Invalid Input");
continue; // Skip the swapping. Ask for input again.
}
// A number must be swapped by now. If not, then throw error.
if (!swap(array, number)){
System.err.println("The number you entered can't be moved.");
}
display(array);
completed = checkForCompletion(array);
}
System.out.println("Congratulations! You have successfully completed the puzzle. :)");
}
/**
* A method to display the puzzle current state
* @param array Current state of the puzzle
*/
private static void display(final int[][] array) {
System.out.println("---------------------");
for (int i = 0; i < 4; i++) {
System.out.print("| ");
for (int j = 0; j < 4; j++) {
System.out.print((array[i][j] == 0?" ":(array[i][j]<10?" "+array[i][j]:array[i][j])) + " | ");
}
System.out.println("\n---------------------");
}
}
/**
* A method to get a number to move in the puzzle
* @return number accepted. 0 in case of invalid input (Exception)
*/
private static int input(){
System.out.print("Enter the number to move : ");
int num = 0;
try{
num = Integer.parseInt(br.readLine());
} catch(IOException e){
System.err.println("Invalid input. Not a number!");
}
return num;
}
/**
* A method to check if user input number is valid
* @param array current state of the puzzle
* @param number number to check if present in the puzzle
* @return
*/
private static boolean isValidInput(final int[][] array, int number){
if (number < 1 && number > 15)
return false;
// Check if the number is present in the puzzle, so that we can move
for (int i = 0; i < 4; i++){
for (int j = 0; j < 4; j++) {
if (number == array[i][j]) {
return true;
}
}
}
return false;
}
/**
* A method to swap the number with empty column
* @param array Current state of the puzzle
* @param number number to swap with
* @return true if number is swapped. false if can't be swapped
*/
private static boolean swap(final int[][] array, int number) {
// Determine the position of the "number to be swapped" in the matrix
int row=0, column=0;
boolean found = false;
for (row=0; !found && row<4; row++){
for (column=0; !found && column<4; column++){
if(array[row][column] == number){
found = true;
//System.out.println("Found number at position "+row+"["+column+"]");
break;
}
}
}
row--; //decremented row because once we broke from inner loop, program did row++ and then check the condition !found && row<4
if (!found){
System.err.println("Invalid number");
return false;
}
boolean swapped = false;
// row[column] now holds the number, check if any adjacent value is 0 so that we can swap
// A number can be swapped only if any of left/right/top/bottom value is 0
if (column > 0){ // Can check left
//System.out.println("row: "+row+", column: "+column+", checking left");
if (array[row][column-1] == 0){ // Got empty at left. Can swap
array[row][column-1] = array[row][column];
array[row][column] = 0;
swapped = true;
}
}
if (!swapped && column < 3){ // Can check right
//System.out.println("row: "+row+", column: "+column+", checking right");
if (array[row][column+1] == 0){ // Got empty at left. Can swap
array[row][column+1] = array[row][column];
array[row][column] = 0;
swapped = true;
}
}
if (!swapped && row > 0){ // Can check top
//System.out.println("row: "+row+", column: "+column+", checking top");
if (array[row-1][column] == 0){ // Got empty at left. Can swap
array[row-1][column] = array[row][column];
array[row][column] = 0;
swapped = true;
}
}
if (!swapped && row < 3){ // Can check bottom
System.out.println("row: "+row+", column: "+column+", checking bottom");
if (array[row+1][column] == 0){ // Got empty at left. Can swap
array[row+1][column] = array[row][column];
array[row][column] = 0;
swapped = true;
}
}
return swapped;
}
/**
* A method to check if the puzzle is completed
* @param array current state of the puzzle
* @return true if puzzle is completed. false otherwise
*/
private static boolean checkForCompletion(final int[][] array) {
//System.out.println("Checking for completion.");
int counter = 1;
for (int row = 0; row < 4; row++){
for (int column = 0; column < 4 && counter < 16; column++, counter++) {
if (array[row][column] != counter){
//System.out.println("Not completed because value of puzzle["+row+"]["+column+"] is "+array[row][column]+", not "+counter);
return false;
}
}
}
return true; // Control will come here only if everything is fine.
}
}well you need something to "follow" your instruction
public static void main(String[] args) {
// TODO code application logic here
int a = 5, b = 10;
if(a>5)
if(b>5) {
System.out.println("b is "+b);
}
else
System.out.println("a is "+a);
} public static void main(String[] args) {
// TODO code application logic here
int p,q = 10;
for(p=1; p<=5; ++p)
q = p++;
--q;
} public static void main(String[] args) {
// TODO code application logic here
int a = 5, b = 10;
if(a>5)
[b]{[/b]
if(b>5) {
System.out.println("b is "+b);
}
[b]}[/b]
else
System.out.println("a is "+a);
}
thanks sujay, and second question?
@Liverpool_fan
got your point now after reading sujay's post, i was confused, thanks buddy
p=1;
while(p<=5)
{
q=p; //first step of q=p++
p=p+1; //2nd step of q=p++
++p;
}
I had a feeling that something was missing. Now I got it . public static void main(String[] args) {
// TODO code application logic here
int a = 5, b = 10;
if(a>5)
[b]{[/b] //body of first [b]if[/b] starts from here
if(b>5) {
System.out.println("b is "+b);
}
else
System.out.println("a is "+a);
}
[b]}[/b] //till here
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;
class Client extends JFrame implements ActionListener {
private JTextField txtFile;
public static void main(String args[]){
/* Create and display the client form */
Client clientForm = new Client();
clientForm.Display();
}
public void Display(){
JFrame frame = new JFrame();
frame.setTitle("Client");
FlowLayout layout = new FlowLayout();
layout.setAlignment(FlowLayout.LEFT);
JLabel lblFile = new JLabel("Filename:");
txtFile = new JTextField();
txtFile.setPreferredSize(new Dimension(150,30));
JButton btnTransfer = new JButton("Transfer");
btnTransfer.addActionListener(this);
JPanel mainPanel = new JPanel();
mainPanel.setLayout(layout);
mainPanel.add(lblFile);
mainPanel.add(txtFile);
mainPanel.add(btnTransfer);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setVisible(true);
}
public void actionPerformed(ActionEvent e) {
/* File Open Dialog box allows the user to select a file */
JFileChooser fileDlg = new JFileChooser();
fileDlg.showOpenDialog(this);
String filename = fileDlg.getSelectedFile().getAbsolutePath();
txtFile.setText(filename);
try{
/* Try to connect to the server on localhost, port 5555 */
Socket sk = new Socket("192.168.0.11", 5555);
OutputStream output = sk.getOutputStream();
/* Send filename to server */
OutputStreamWriter outputStream = new OutputStreamWriter(sk.getOutputStream());
outputStream.write(fileDlg.getSelectedFile().getName() + "\n");
outputStream.flush();
/* Get reponse from server */
BufferedReader inReader = new BufferedReader(new InputStreamReader(sk.getInputStream()));
String serverStatus = inReader.readLine(); // Read the first line
/* If server is ready, send the file */
if ( serverStatus.equals("READY") ){
FileInputStream file = new FileInputStream(filename);
byte[] buffer = new byte[sk.getSendBufferSize()];
int bytesRead = 0;
long t= System.currentTimeMillis();
while((bytesRead = file.read(buffer))>0)
{
output.write(buffer,0,bytesRead);
}
//long n=System.currentTimeMillis();
//long d=n-t;
output.close();
file.close();
sk.close();
//JOptionPane.showMessageDialog(this, "Transfer complete \n Time taken "+d+" Mili-seconds");
}
}
catch (Exception ex){
/* Catch any errors */
JOptionPane.showMessageDialog(this, ex.getMessage());
}
}
}import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;
class Tester extends JFrame implements ActionListener
{
private JTextField txtFile;
public static void main (String[] args)
{
Tester mytester = new Tester();
mytester.display();
}
public void display()
{
JFrame frame = new JFrame();
frame.setTitle("Download Tester");
FlowLayout layout = new FlowLayout();
layout.setAlignment(FlowLayout.LEFT);
JLabel lblFile = new JLabel("File:");
txtFile = new JTextField();
txtFile.setPreferredSize(new Dimension(150,30));
JButton selectbutton = new JButton("Select");
selectbutton.addActionListener(this);
JButton sendbutton = new JButton("Send");
sendbutton.addActionListener(this);
JPanel mainPanel = new JPanel();
mainPanel.setLayout(layout);
mainPanel.add(lblFile);
mainPanel.add(txtFile);
mainPanel.add(selectbutton);
mainPanel.add(sendbutton);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setVisible(true);
}
public void actionPerformed(ActionEvent event)
{
if(event.getSource()==selectbutton)
{
JFileChooser fileDlg = new JFileChooser();
fileDlg.showOpenDialog(this);
String filename = fileDlg.getSelectedFile().getAbsolutePath();
txtFile.setText(filename);
}
else
{
try
{
Socket sk = new Socket("192.168.0.11", 5555);
OutputStream output = sk.getOutputStream();
OutputStreamWriter outputStream = new OutputStreamWriter(sk.getOutputStream());
outputStream.write(fileDlg.getSelectedFile().getName() + "\n");
outputStream.flush();
BufferedReader inReader = new BufferedReader(new InputStreamReader(sk.getInputStream()));
String serverStatus = inReader.readLine();
if ( serverStatus.equals("READY") )
{
FileInputStream file = new FileInputStream(filename);
byte[] buffer = new byte[sk.getSendBufferSize()];
int bytesRead = 0;
long t= System.currentTimeMillis();
while((bytesRead = file.read(buffer))>0)
{
output.write(buffer,0,bytesRead);
}
output.close();
file.close();
sk.close();
JOptionPane.showMessageDialog(this, "Transfer complete");
}
}
catch (Exception ex)
{
JOptionPane.showMessageDialog(this, ex.getMessage());
}
}
}
}}
public class Trial {
public static void main(String args[]) throws CustomException{
try{
//Code that generates Arithmetic division by zero exception
}
catch(ArithmeticException e){
throw new CustomException();
}
}
}
class CustomException extends ArithmeticException{
@Override
public String getMessage() {
// return custom message
return "Division by zero was attempted !! ";
}
}import java.util.Random;
public class DeckOfCards {
private Card deck[];
private int currentCard;
private final int NUMBER_OF_CARDS = 52;
private Random randomNumber;
public DeckOfCards(){
String faces[] = {"ACE", "TWO", "THREE", "FOUR", "FIVE", "SIX", "SEVEN", "EIGHT", "NINE", "TEN", "JACK", "QUEEN", "KING"};
String suits[] = {"HEARTS", "DIMOND", "SPADES", "CLUBS"};
deck = new Card[NUMBER_OF_CARDS];
currentCard = 0;
randomNumber = new Random();
for(int count = 0; count<deck.length; count++){
deck[ count ] = new Card(faces[ count % 13 ], suits[ count / 13 ]);
}
}
public void shuffle(){
currentCard = 0;
for(int first = 0; first<deck.length; first++){
int second = randomNumber.nextInt(NUMBER_OF_CARDS);
Card temp = deck[first];
deck[first] = deck[second];
deck[second] = temp;
}
}
public Card dealCard(){
if(currentCard < deck.length )
return deck[ currentCard++ ];
else
return null;
}
}public class DeckOfCardTest {
public static void main(String[] args) {
DeckOfCards myDeckOfCards = new DeckOfCards();
myDeckOfCards.shuffle();
for(int i = 0; i<13; i++ ){
System.out.printf("%-20s%-20s%-20s%-20s\n", myDeckOfCards.dealCard(), myDeckOfCards.dealCard(),myDeckOfCards.dealCard(),myDeckOfCards.dealCard());
}
}
}
public class BarcodeEAN128 extends Barcode {
//some variables decalration
static {
final Map m = new HashMap();
//some processing
}
}
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class triangleFormation {
public static boolean isTriangle (int a, int b, int c){
if (c>a+b || a>b+c || b>a+c ){
return false;
} else{
return true;
}
}
public static void main (String [] args)throws IOException {
BufferedReader bufferedreader = new BufferedReader(new InputStreamReader(System.in));
String s = bufferedreader.readLine();
String r = bufferedreader.readLine();
String t = bufferedreader.readLine();
int m = Integer.parseInt(s);
int n = Integer.parseInt(r);
int o = Integer.parseInt(t);
System.out.println("the triangle is " + isTriangle (m,n,o));
}
}
The code is valid although logic is flawed. You should be returning `false` if `c>a+b || a>b+c || b>a+c`.Guys having trouble providing keyboard input as arguments to a function especially when passing more than 1 argument. Written a java code i procedural style ( without any use of objects) to show if a triangle can be formed when we provide three integer inputs.
The code works flawlessly when manually providing arguments to the method isTriangle.
But when using providing inputs through keyboard , it throws error. Providing the code below:
Code:import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; public class triangleFormation { public static boolean isTriangle (int a, int b, int c){ if (c>a+b || a>b+c || b>a+c ){ return true; } else{ return false; } } public static void main (String [] args)throws IOException { BufferedReader bufferedreader = new BufferedReader(new InputStreamReader(System.in)); String s = bufferedreader.readLine(); String r = bufferedreader.readLine(); String t = bufferedreader.readLine(); int m = Integer.parseInt(s); int n = Integer.parseInt(r); int o = Integer.parseInt(t); System.out.println("the triangle is " + isTriangle (m,n,o)); } }
I don't know if the process of providing keyboard input is correct or not. Only thing i found that its a hassle i java or i don't know some basic concepts. Providing inputs was so easy in c++.
Please throw some light into it guys.
Nope mate the logic isn't flawed. See a,b and c are three sides of a triangle and atleast one side should be greater than the sum of the other two sides for a triangle to form.
If any of the above conditions are satisfied, true should be returned and if not, then false. Code is tested and is working correctly. Just asking how to enter input values manually through console i.e keyboard input.
I didn't get the bold part . Can you plz be a bit clear on that part mate?
1
1
101 1 10
Just a bit? Lol
Just a bit? Lol
Thanks for pointing that out man or i would have been a joke for all elementary school students.
How are you running the program?My head was screwed up a bit.
Buddy this is what i don't understand. In java i guess we can't input like that or atleast i think i don't know how to.
See when you input a single value , java takes only strings and invokes a readline method through a bufferreader object. Then that string has to be converted into an integer and those integers are passed as arguments for a respective method.
It works for a single argument but not for 3 in this case. I'm totally confused.
Can you please show me with proper java syntax?
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Power {
public static double power(double x ,int n){
if (n==0){
return 1;
} if (n%2==0){
double b =Math.pow(n, x);
return b;
}else{
double recurse = power(x,n-1);
return x*recurse;
}
}
public static void main (String [] args) throws IOException{
BufferedReader bufferedreader = new BufferedReader(new InputStreamReader(System.in));
String s = bufferedreader.readLine();
String r = bufferedreader.readLine();
double m = Double.parseDouble(s);
int p = Integer.parseInt(r);
System.out.println (power (m,p));
}
}public double power(double x, int n)
{
if(n == 0)
return 1;
else if(n%2 == 0)
return power(x, n/2)*power(x, n/2);
else
return x*power(x,n-1);
}import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Euclid {
public static int gcd (int a, int b){
int r = a % b;
if (r == 0){
return b;
} else {
int recurse = gcd (b,r);
return recurse;
}
}
public static void main (String [] args) throws IOException{
BufferedReader bufferedreader = new BufferedReader(new InputStreamReader(System.in));
String s = bufferedreader.readLine();
String r = bufferedreader.readLine();
int p = Integer.parseInt(s);
int q = Integer.parseInt(r);
System.out.println (gcd(p,q));
}
}You interpreted it wrongly mate.
void foo(a,b){
file.open(a);
file.write(b);
}
int bar(a,b){
if(file.open(a)){
if(file.write(b))
return 0;
else
return 1;
}
return 2;
} /* int recurse = gcd(a,b);
* return recurse;
*/
return gcd(a,b);mport java.util.Scanner.*;
public class Calc
{
public static void main (String args[])
{ int result,a,b,c;
Scanner scan=new Scanner(System.in);
System.out.println("Enter the operation to perform: 1-->+ 2-->- 3-->/ 4-->* ");
c=scan.nextInt();
System.out.println("Enter the two numbers: a and b");
a=scan.nextInt();
b=scan.nextInt();
switch(c)
{ case '1':
{ result=a+b;
System.out.println("Result is "+result);
break;
}
case '2':
{ result=a-b;
System.out.println("Result is "+result);
break;
}
case '3':
{ result=a*b;
System.out.println("Result is "+result);
break;
}
case '4':
{ result=a/b;
System.out.println("Result is "+result);
break;
}
default:
{ System.out.println("Wrong operator choice!!!");
break;
}
}
}
}Calc.java:29: error: cannot find symbol
Scanner scan=new Scanner(System.in);
^
symbol: class Scanner
location: class Calc
Calc.java:29: error: cannot find symbol
Scanner scan=new Scanner(System.in);
^
symbol: class Scanner
location: class Calc
2 errorsimport java.util.[B]Scanner[/B]import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
/**
*
* @author SudhiR
*/
class Calci implements ActionListener
{
char op;
String value="",cv="";
int ctr=0;
Double v1,v2,ans;
Frame fr;
MenuBar mBar;
Menu f,e;
MenuItem q,c,p;
JButton num0,num1,num2,num3,num4,num5,num6,num7,num8,num9,bDot,bAdd,bSub,bDiv,bMul,bSqrt,bPer,clear,bCE,back,equals,inv;
TextField txt;
Panel p1,p2,p3,p4,p5;
Calci(){
fr=new Frame("Calculator");
fr.setDefaultCloseOperation(Frame.EXIT_ON_CLOSE);
txt=new TextField(35);
txt.setText("0");
txt.setEnabled(false);
mBar=new MenuBar();
f=new Menu("File");
e=new Menu("Edit");
q=new MenuItem("Quit");
c=new MenuItem("Copy");
p=new MenuItem("Paste");
num0=new JButton("0");
num1=new JButton("1");
num2=new JButton("2");
num3=new JButton("3");
num4=new JButton("4");
num5=new JButton("5");
num6=new JButton("6");
num7=new JButton("7");
num8=new JButton("8");
num9 =new JButton("9");
bAdd=new JButton("+");
bSub=new JButton("-");
bDiv=new JButton("/");
bMul=new JButton("*");
bSqrt=new JButton("Sqrt");
bPer=new JButton("%");
clear=new JButton("C");
bCE=new JButton("CE");
back=new JButton("BackSpace");
equals=new JButton("=");
bDot=new JButton(".");
inv=new JButton("+/-");
p1=new Panel();
p2=new Panel();
p3=new Panel();
p4=new Panel();
p5=new Panel();
mBar.add(f);
mBar.add(e);
f.add(q);
e.add(c);
e.add(p);
p1.add(back);
p1.add(clear);
p1.add(bCE);
p2.add(num7);
p2.add(num8);
p2.add(num9);
p2.add(bAdd);
p2.add(bMul);
p3.add(num4);
p3.add(num5);
p3.add(num6);
p3.add(bSub);
p3.add(bDiv);
p4.add(num1);
p4.add(num2);
p4.add(num3);
p4.add(bDot);
p4.add(inv);
p5.add(num0);
p5.add(equals);
p5.add(bSqrt);
p5.add(bPer);
p1.setLayout(new GridLayout(1,3,2,2));
p2.setLayout(new GridLayout(1,5,2,2));
p3.setLayout(new GridLayout(1,5,2,2));
p4.setLayout(new GridLayout(1,5,2,2));
p5.setLayout(new GridLayout(1,4,2,2));
fr.setLayout(new GridLayout(6,1));
fr.setMenuBar(mBar);
fr.setResizable(false);
fr.setSize(300,300);
fr.add(txt);
fr.add(p1);
fr.add(p2);
fr.add(p3);
fr.add(p4);
fr.add(p5);
fr.setVisible(true);
}
public void op()
{
num0.addActionlistener(new ActionListener());
num0.addActionlistener(this);
num1.addActionlistener(this);
num2.addActionlistener(this);
num3.addActionlistener(this);
num4.addActionlistener(this);
num5.addActionlistener(this);
num6.addActionlistener(this);
num7.addActionlistener(this);
num8.addActionlistener(this);
num9.addActionlistener(this);
bAdd.addActionlistener(this);
bSub.addActionlistener(this);
bMul.addActionlistener(this);
bDiv.addActionlistener(this);
bSqrt.addActionlistener(this);
bPer.addActionlistener(this);
equals.addActionlistener(this);
clear.addActionlistener(this);
back.addActionlistener(this);
bCE.addActionlistener(this);
inv.addActionlistener(this);
bDot.addActionlistener(this);
q.addActionlistener(this);
c.addActionlistener(this);
p.addActionlistener(this);
}
//Menu Items//
if(ae.getSource()==q)
{
System.exit(0);
}
else if(ae.getSource()==c)
{
cv+=value;
}
else if(ae.getSource()==p)
{
value+=cv;
}
}import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class EventDemo {
JLabel jlab;
EventDemo() {
// Create a new JFrame container.
JFrame jfrm = new JFrame("An Event Example");
// Specify FlowLayout for the layout manager.
jfrm.setLayout(new FlowLayout());
// Give the frame an initial size.
jfrm.setSize(220, 90);
// Terminate the program when the user closes the application.
jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Make two buttons.
JButton jbtnAlpha = new JButton("Alpha");
JButton jbtnBeta = new JButton("Beta");
// Add action listener for Alpha.
jbtnAlpha.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
jlab.setText("Alpha was pressed.");
}
});
// Add action listener for Beta.
jbtnBeta.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
jlab.setText("Beta was pressed.");
}
});
// Add the buttons to the content pane.
jfrm.add(jbtnAlpha);
jfrm.add(jbtnBeta);
// Create a text-based label.
jlab = new JLabel("Press a button.");
// Add the label to the content pane.
jfrm.add(jlab);
// Display the frame.try below program executionCheck this code out:
Now I'm getting this error "Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0Code:import java.io.*; public class FileOps { public static void main(String args[]) { File file = new File(args[0]); try { BufferedReader in = new BufferedReader(new FileReader(file)); String s; s = in.readLine(); while(s!=null) { System.out.println("Read " + s); s = in.readLine(); } in.close(); } catch(FileNotFoundException e1) { System.err.println("File Not Found" + file); } catch(IOException e2) { e2.printStackTrace(); } } }
at FileOps.main(FileOps.java:13)
Java Result: 1
"
What's the solution?
class NewThread extends Thread{
public void run(){
System.out.println("Child Thread!");
}
}
class ThreadTest{
public static void main(String args[]){
NewThread nt = new NewThread();
nt.start();
System.out.println("Main Thread!");
}
}class NewThread implements Runnable{
public void run(){
System.out.println("Child Thread!");
}
}
public class ThreadTest {
public static void main(String args[]){
[I]Runnable threadJob = new NewThread();
Thread nt = new Thread(threadJob);[/I]
nt.start();
System.out.println("Main thread");
}
} import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class GuiTest {
JFrame frame;
public static void main (String [] args){
GuiTest gui = new GuiTest() ;
try {
gui.go();
}catch (ClassCastException ex){
ex.printStackTrace();
}
}
public void go (){
frame = new JFrame ();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton button = new JButton ("Test Colour");
[B]button.addActionListener(this);[/B]
DrawPanel panel = new DrawPanel();
frame.getContentPane().add(BorderLayout.SOUTH,button);
frame.getContentPane().add(BorderLayout.CENTER,panel);
frame. setSize(300,300);
frame.setVisible(true);
}
public void actionPerformed(ActionEvent event){
frame.repaint();
}
}
class DrawPanel extends JPanel{
public void PaintComponent(Graphics g){
g.fillRect (0,0,this.getWidth(),this.getHeight());
int red = (int)(Math.random()*255);
int blue= (int)(Math.random()*255);
int green = (int)Math.random()*255;
Color randomColor = new Color(red,green,blue);
g.setColor(randomColor);
g.fillOval(70, 70, 100, 100);
}
}And if I don't declare it as final, but only static then the static block is getting processed. Can anyone explain why is it happening??
2)
@piyush deleted the post
saveFile="C:/temp/"+saveFile;
I dont know how to implement hash codes.
Worked flawlessly. Thanks
SELECT * FROM pnotocdm WHERE time > time('now','localtime') LIMIT 4;
package com.example.toggleclock;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AnalogClock;
import android.widget.CompoundButton;
import android.widget.ToggleButton;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final AnalogClock clock = (AnalogClock) findViewById(R.id.AnalogClock);
ToggleButton toggle = (ToggleButton) findViewById(R.id.ToggleButton);
toggle.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
@Override
# public void onClick(View v) {
clock.setVisibility(View.VISIBLE);
}
}
else {
@Override
# public void onClick(View v) {
clock.setVisibility(View.INVISIBLE);
}
}
}
});
}
}<RelativeLayout xmlns:android="*schemas.android.com/apk/res/android"
xmlns:tools="*schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="${packageName}.${activityClass}" >
<ToggleButton
android:id="@+id/ToggleButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:textOn="@string/on"
android:textOff="@string/off"
android:checked="true" />
<AnalogClock
android:id="@+id/AnalogClock"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/ToggleButton"
android:layout_centerHorizontal="true" />
</RelativeLayout>
Get Eclipse Luna, it takes 5 mins to setup, and then code away, luna supports java 8. Also if you need to learn J2EE, just get TomEE. Coding via notepad is not a a very good way at all, you need to debug your code, see the console, use an IDE.
Thanks, is there any local edition available? The price is out of my range.@Tkin
Hello my friend.
I'm a huge fan of cay horstmann. Try this for java 8 - Buy Java SE 8 for the Really Impatient Book Online at Low Prices in India | Java SE 8 for the Really Impatient Reviews & Ratings - Amazon.in
Their Core series act has a very good reference. So i suggest you to try this.
Btw buddy i don't recommend the scjp book by sierra and bates to a newbie into the world of java. I would suggest their head first book to absolute beginners.
Courses on coursera and edX are actually quite good. You should try those when they start.
public class test implements Runnable{
public void run(){
for(int i=1;i<6;i++){
System.out.println(" "+i);
try{
Thread.sleep(500);
}catch(InterruptedException E){
System.out.println("Thread Interrupted");
}
}
System.out.println("Run one is terminated");
}
public static void main(String agrs[]){
test obj = new test();
Thread objT = new Thread(obj);
objT.start();
try{
objT.join();
}
catch(InterruptedException e){
}
System.out.println("Main one is terminated");
}
}1. As Runnable is an interface, you cannot initialize it. But if you implement Runnable in your class you need to initialize your class to start a thread. Your class contains the main method which is Static, so you cannot refer to your test class object using 'this' i.e you cannot write this.start as its a Static method. Hence you need to initialize your test class object in the main method.
public class ThreadTest extends Thread {
public static void main(String agrs[]){
for(int i=1;i<6;i++){
System.out.println(" "+i);
try{
Thread.sleep(500);
}catch(InterruptedException E){
System.out.println("Thread Interrupted");
}
}
System.out.println("Main thread is terminated");
}
}Main one is terminated
1
2
3
4
5
Run one is terminatedOk. Thank you!
Hurt feelings? lulz.Thanks man, that really helped!
BTW there is just one java. Just this one.
And I get it, since you are from Python, learning Java is somewhat difficult for you. So, just learn this Oracle(earlier called Sun) Java, and you are good to go with Android. If you want to learn Native Android or with frameworks like PhoneGap etc, some basic understanding in Java might be helpful.
Get some good Java book, for getting basic understanding. Just one tip, don't compare Python with Java. Boiler plate codes are a common sight in Java, and LoC will be high. But that is what makes Java, as "Java".
import java.util.Scanner;
public class PatternNumPyramid {
public static void main(String args[]) {
System.out.println("Enter the number of rows you want to print");
Scanner input = new Scanner(System.in);
int numOfRows = input.nextInt();
int i, j, k; [I]//to be used in for{} loops[/I]
boolean flag; [I] //flag is used to ensure that loop k(for space) runs only once after coming to next line[/I]
for(i=0 ; i<=numOfRows; i++){ [I]//i is to go to next line[/I]
flag=true;
for(j=i; j>=0; j--){ [I]//j is to print in decreasing order[/I]
if(flag){
for(k=numOfRows-j; k>0; k--){ [I] //k is to print spaces[/I]
System.out.print(" ");
}flag=false;
}
System.out.print(j);
if(i>0){
if(j==0){
for(int x=1; x<=i; x++){ [I] //x is to print in increasing order[/I]
System.out.print(x);
}
}
}
}
System.out.println("");
}
}
}[CENTER] 0
101
21012
3210123
[/CENTER]did you find any reliable source for learning spring framework?Are free tutorials for it available online?Also can you suggest from where can one learn other frameworks like strutts,hibernate etc?
. Also, do not hesitate.
As long as all your class variables are not directly accessible from outside, your class can be considered encapsulated. As per the Javabeans standards, you must define public getter and setter methods to get or set the values of the variables. Also, you must define public methods to operate on your class variables. Your class variables should remain private at all times.
Did you fix the issue?? How did you fix it??
(pseudocode)
loop i from 1 to maxIterations
spaceCount = maxIterations - (i*2); //Since there are two stars
loop j from 1 to i
str = str + "*"
end loop
loop j from 1 to spaceCount
str = str + " " //append space
end loop
loop j from 1 to i
str = str + "*" //Ending stars
end loop
print str
end loopimport java.awt.Color;
import java.awt.Graphics;
import javax.swing.JFrame;
public class rectangle3 {
public static void main(String[] args) {
JFrame f1 = new JFrame("myrect") {
public void paint(Graphics g) {
g.setColor(Color.WHITE);
g.fillRect(0, 0, 500, 500);
g.setColor(Color.BLACK);
g.drawString("Hello", 90, 80);
}
};
f1.setSize(500, 500);
f1.setVisible(true);
f1.setDefaultCloseOperation(f1.EXIT_ON_CLOSE);
}
}interface First{
// default method
default void show(){
System.out.println("Default method implementation of First interface.");
}
}
interface Second{
// Default method
default void show(){
System.out.println("Default method implementation of Second interface.");
}
}
// Implementation class code
class Question44 implements First, Second{
// Overriding default show method
public void show(){
// Call show() of First interface.
// Call show() of Second interface.
}
public static void main(String args[]){
Question44 q = new Question44();
q.show();
}
}class Question44 implements First, Second {
// Overriding default show method
public void show() {
// Call show() of First interface.
First.super.show();
// Call show() of Second interface.
Second.super.show();
}
public static void main(String args[]) {
Question44 q = new Question44();
q.show();
}
}Because the method is not static. You can only call static methods using the class name qualifier.
Don't know about others but Herbert Schildt's book is best for Java. I think it's called Java complete reference or something.
Yeah, this one is best of absolute beginners.
+1 for this. My college professor(during bachelor degree) consulted this book and Head First. Both of them are very good. Great for learning Java. It's a shame I haven't written much Java after my Bachelor's degree(other than for Android).
Yeah worth it. Also, a whole book dedicated to threads. Wow. @dDesmond David could use it maybe.
Not really but depends on your use case. It's most helpful if you are doing something like batch processing.
These don't run in a container by default. You will have to write a Dockerfile for your build to run in a container.
Like I said, batch processing or data processing. Like if you have to process a large number of files, then you will have to use threads to process them parallelly to increase throughput. But then again you don't have to know too much for most common use cases, just general idea is usually enough.
Doesn't spring/play comes with its own container which creates a independent thread for each (http)request and those threads are managed until the purpose is served.
If you are speaking about servlet container, then yes. But this is not something spectacular, a servlet container is basically same as an ordinary web server with the added functionality of running web applications and routing the requests to the appropriate web applications. As such, like any other web server, it creates new threads to handle requests.
But not by us, the request thread's lifecycle is handled internally by the servlet container. We can spawn new threads for our own purposes though INSIDE the servlets but not in the servlet container itself.
Seems like a custom written method. It's probably outside the main() method in the same class. Do you have the code for the whole class?
public class Main extends Thread {
public static int amount = 0;
public static void main(String[] args) {
Main thread = new Main();
thread.start();
// Wait for the thread to finish
while(thread.isAlive()) {
System.out.println("Waiting...");
}
// Update amount and print its value
System.out.println("Main: " + amount);
amount++;
System.out.println("Main: " + amount);
}
public void run() {
amount++;
}
}Here's what's happening:
isAlive() just returns true or false based on whether the thread is alive or not. Since your thread is only incrementing the value of `amount` exactly once, the thread does not live for long. Once it finishes executing all lines of code in the `run()` method, the thread terminates immediately, that is why it prints "Waiting..." twice because it terminates quickly. You can get the thread to be alive longer by calling a `Thread.sleep()` method in your `run()` method. This will result in many more "Waiting..." messages to be printed.
The above example is demonstrating that you can increment the value of `amount` in parallel. Though it is not a very good example.
It allows you to run things in parallel. For example, if you were to create a UI application in a single thread, you would not want the whole application to freeze if you want to trigger some long running job. In this case, you run the job in a separate thread and let your UI application run in the main thread. This way your UI application does not freeze and the job goes on in the background.
Consider this code:
package come.desmonddavid.ThreadTest;
public class ThreadTest {
public static void main(String[] args) {
Runnable r = () -> {
System.out.println("Starting thread "+Thread.currentThread().getId());
for(int i = 0; i < 10; i++) {
long sleepTime = 1000L;
try {
System.out.println(Thread.currentThread().getId()+": Sleeping for "+sleepTime+" milliseconds");
Thread.sleep(sleepTime);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("Exiting thread "+Thread.currentThread().getId());
};
Thread t1 = new Thread(r);
Thread t2 = new Thread(r);
Thread t3 = new Thread(r);
t1.start();
t2.start();
t3.start();
}
}Starting thread 11
11: Sleeping for 1000 milliseconds
Starting thread 13
Starting thread 12
12: Sleeping for 1000 milliseconds
13: Sleeping for 1000 milliseconds
12: Sleeping for 1000 milliseconds
11: Sleeping for 1000 milliseconds
13: Sleeping for 1000 milliseconds
13: Sleeping for 1000 milliseconds
12: Sleeping for 1000 milliseconds
11: Sleeping for 1000 milliseconds
11: Sleeping for 1000 milliseconds
13: Sleeping for 1000 milliseconds
12: Sleeping for 1000 milliseconds
11: Sleeping for 1000 milliseconds
12: Sleeping for 1000 milliseconds
13: Sleeping for 1000 milliseconds
Exiting thread 11
Exiting thread 13
Exiting thread 12Threads can also make your code very complicated by potentially introducing problems such as race conditions, deadlocks, ConcurrentModificationExceptions, etc. So, you have to be very careful when using Threads. You should read up about thread safety in Java to see why this is important.
Extending a Thread class may be beneficial in case when you already have some Thread functionality defined either as an abstract class or an existing concrete class and you need to enhance it's functionality. This however is a very special case and for most cases you will not need to extend a thread class since you simply need to run some piece of code. In this latter case, implementing a Runnable is simpler and thus preferable over extending a Thread class.
What is ADT?
package come.desmonddavid.ThreadTest;
public class MessagePassingTest {
public static void main(String[] args) throws InterruptedException {
SquareThread st = new SquareThread();
st.start();
Thread.sleep(1000);
st.feedValue(2);
Thread.sleep(1000);
st.feedValue(4);
Thread.sleep(1000);
st.feedValue(10);
Thread.sleep(1000);
st.quit();
}
}
class SquareThread extends Thread {
private volatile boolean valChanged = false;
private volatile boolean quitThread = false;
private volatile int value = 0;
@Override
public void run() {
System.out.println("Starting SquareThread");
while(true) {
if(quitThread) {
System.out.println("Exiting SquareThread");
return;
}
if(valChanged) {
System.out.println("Square of " + value + " is " + value * value);
valChanged = false;
}
}
}
public void feedValue(int value) {
this.value = value;
valChanged = true;
}
public void quit() {
quitThread = true;
}
}feedValue() method, waiting 1 second between feeding values three times. After than the main() method calls quit() and that terminates the thread. This is a very simple example, so I think you should be able to understand just by looking at it. If you have any doubts, then ask here.
Sorry, that was a force of habit. We use Java 8 at work, so I have developed a habit of using lambdas.
Runnable r = () -> {} is equivalent to:Runnable r = new Runnable() {
public void run() {
// Do something
}
}Because Thread has multiple overloaded constructors, one of them takes a Runnable as an argument. Reference: Thread (Java Platform SE 8 )
I still take reference from Baeldung, and I have over 9 years of experience working in software development.
I think they are okay for beginners.
This is good. I also wanted to be like this but I am so much use to Java 7 that even when working with Java 8 I continue old practices because of which I have been struggling a lot lately.
import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;
public class Solution {
// Complete the findNumber function below.
static String findNumber(List<Integer> arr, int k) {
String answer = "NO";
for (Integer i : arr) {
if (i == k) {
answer = "YES";
break;
}
}
return answer;
}
public static void main(String[] args) throws IOException {
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(System.out));
int arrCount = Integer.parseInt(bufferedReader.readLine().trim());
List<String> arrTemp = new ArrayList<>();
IntStream.range(0, arrCount).forEach(i -> {
try {
arrTemp.add(bufferedReader.readLine().replaceAll("\\s+$", ""));
} catch (IOException ex) {
throw new RuntimeException(ex);
}
});
List<Integer> arr = arrTemp.stream()
.map(String::trim)
.map(Integer: parseInt)
.collect(toList());
int k = Integer.parseInt(bufferedReader.readLine().trim());
String res = findNumber(arr, k);
bufferedWriter.write(res);
bufferedWriter.newLine();
bufferedReader.close();
bufferedWriter.close();
}
};It's adding each line to the array after removing whitespace from the end of the string. It's using regular expressions to identify the whitespaces.
This is the Java 8 Stream API. You can use streams to chain operations on some collections such as on list. Here, the stream of the string array is being transformed into an integer stream and then collected into a list.
Applied the tags,hopefully it looks better now.
// Complete the findNumber function below. which means that the main() method was already like that in the code but I find it hard to believe.
Yeah, looks like the main() method is the same from the problem statement.
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class Soultion {
// Complete the findNumber function below.
static String findNumber(List<Integer> arr, int k) {
String answer = "NO";
for (Integer i : arr) {
if (i == k) {
answer = "YES";
break;
}
}
return answer;
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int arrLen = sc.nextInt();
List<Integer> arr = new ArrayList<Integer>();
for (int i = 0; i < arrLen; i++) {
arr.add(sc.nextInt());
}
int k = sc.nextInt();
String res = findNumber(arr, k);
System.out.println(res);
sc.close();
}
}It helped me to write code, improving problem solving skills and gain confidence. I never had any high rank, so can't comment on that part. I used to spend a lot of time on understanding the easy questions and writing a solution and running the test cases.
The code is from Hackerrank I guess. They have run all their test cases and match the output of the code against each test case, which are probably in some files. I am assuming this the reason they are using bufferedreader.
Indirectly, Yes. Directly, may be.
Hey man! Do you still participate in these?
((/?)([A-Z]{3})([0-9]{1,15}))ABC123/DEF1223456/GHI12345678980834import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegExCHGSTagPattern {
public static void main(String[] args) {
String input1 = "ABC123";
String input2 = "ABC123/DEF1223456/GHI12345678980834";
Pattern p = Pattern.compile("((/?)([A-Z]{3})([0-9]{1,15}))");
Matcher m1 = p.matcher(input1);
Matcher m2 = p.matcher(input2);
System.out.println("output1-"+m1.matches());
while(m2.find()) {
System.out.println(m2.group()+"-"+p.matcher(m2.group()).matches());
}
System.out.println("output2-"+m2.matches());
}
}([A-Z]{3}\d{1,15})\/?\d+ with \d{1,15} since you have a constraint on the number of digits.
I am trying but its not working in IDE. i did match the strings on *regex101.com/
Pattern p = Pattern.compile("([A-Z]{1,3}[0-9]{1,15}/?)+");[A-Z]{1,3} --> any character from A to Z which will repeat for minimum 1 to maximum 3 times [0-9]{1,15} --> any number from 0 to 9 which will repeat for minimum 1 to maximum 15 times/? --> / can come for zero or more times [A-Z]{1,3}[0-9]{1,15}/? --> ([A-Z]{1,3}[0-9]{1,15}/?)+
In Java you have to escape the backslashes for regex Strings.
private static final String pattern = "([A-Z]{3}\\d{1,15})\\/?";class Main {
private static final String pattern = "([A-Z]{3}\\d{1,15})\\/?";
private static final String input = "ABC123/DEF1223456/GHI12345678980834";
public static void main(String[] args) {
Pattern p = Pattern.compile(pattern);
Matcher m = p.matcher(input);
while(m.find()) {
System.out.println(m.group(1));
}
}
}ABC123
DEF1223456
GHI12345678980834group(1) will match the bracketed group in the regex. Updated the answer to reflect that.
if you add m.matches() line at the end, it returns false. This is exactly my question, we are able to see the group from the entire input which matches, I am wondering why m.matches() return false at the end.
It worked! Adding the + symbol at the end of the entire group returns true. You are a saviour <3
\d instead of [0-9] since it matches single digits, while the [] notation works if you are creating an alphanumeric pattern.