Here are some java samples codes that may help you.Factorial
Prime #
ASCII code printing
See how the #s are stored in memory(this helps u to understand binary operations)
XML Parser
Read Contents Of URL
Date Formatting
To start a process(Spawn a process within the jvm)
Hide Password From CommandLine
Tells you the domain name and IP of the machine
XML Parser
XML Parser
Create Text to speech with JSAPI
A Desktop Telephone ApplicationMore samples will be added...
Factorial.java
import java.util.*;
import java.lang.*;
public class Factorial {
public static void main(String[] args)
{
if (args.length == 0)
System.out.println("Example: java Factorial 10");
try
{
for (int i=0; i < args.length; i++)
{
System.out.print("Fact of Param # " + (i+1) + ": " + Fact(args[i]));
}
}
catch(Exception E)
{
System.out.println(E.getMessage());
}
}
public static long Fact(String f) throws Exception
{
int f1 = Integer.parseInt(f);
long Result = 1;
if (f1 < 0)
throw new Exception("I can not calculate this!");
if (f1 > 20)
throw new Exception("that is a big ####");
try
{
for (int j=1; j <= f1; j++)
Result *= j;
}
catch(Exception e)
{
System.out.println(e.getMessage());
throw e;
}
return Result;
}
}
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Prime.java
import java.util.*;
import java.lang.Math;
public class Prime {
public static void main(String[] args)
{
for (int i = 1; i < 1500; i++)
if (isPrime(i))
System.out.println(i);
}
public static boolean isPrime(int n)
{
for (int i = 2; i <= Math.sqrt(n); i++)
{
if (n % i == 0)
return false;
}
return true;
}
}
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public class ASCII_code{
public static void main(String argv[]){System.out.println("Value\tChar\tValue\tChar\tValue\tChar\tValue\tChar\tValue\tChar\t");
int c=1;
while (c < 256)
{
for (int col = 0; col < 5 && c < 256; col++, c++)
System.out.print(c + "\t" + (char)c + "\t");
System.out.println();
}
}
}
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import java.awt.*;
import java.awt.event.*;/*
RUN THIS PROGRAM AND ENTER 2 VALUES(+ve or -ve), then CLICK ON
THE OPERATOR BUTTON...SEE THE RESULT in binary(exactly the
way it is stored in memory).
*/
class BinApp extends Frame {
TextField T1, T2;
Label Result, Error;
Button bAND, bOR, bXOR, bRShift, bLShift,bRRShift;BinApp(){
Panel P = new Panel();
Panel P_edit = new Panel();
Panel P_btn = new Panel();
Panel P_result = new Panel();
add(P, "Center");
P.setLayout(new GridLayout(3, 0));
P.add(P_edit);
T1 = new TextField(20);
T2 = new TextField(20);
P_edit.add(T1);
P_edit.add(T2);
P.add(P_btn);
bAND = new Button("&");
bOR = new Button("|");
bXOR = new Button("^");
bRShift = new Button(">>");
bLShift = new Button("<<");
bRRShift = new Button(">>>");
P_btn.setLayout(new GridLayout(3, 0));
P_btn.add(bAND);
P_btn.add(bOR );
P_btn.add(bXOR);
P_btn.add(bRShift);
P_btn.add(bLShift);
P_btn.add(bRRShift);
P.add(P_result);
Result = new Label(" ");
Error = new Label("");
P_result.setLayout(new GridLayout(2, 0));
P_result.add(Result);
P_result.add(Error);
ButtonHandler handler = new ButtonHandler();
bAND.addActionListener(handler);
bOR.addActionListener(handler);
bXOR.addActionListener(handler);
bRShift.addActionListener(handler);
bLShift.addActionListener(handler);
bRRShift.addActionListener(handler);
Error.setForeground(Color.red);
}class ButtonHandler implements ActionListener{
public void actionPerformed(ActionEvent e){
Error.setText("");
String s = e.getActionCommand();
int n1 = getInt(T1.getText());
int n2 = getInt(T2.getText());
if (s=="&")
Result.setText(printBin(n1&n2));
else if (s=="|")
Result.setText(printBin(n1|n2));
else if (s=="^")
Result.setText(printBin(n1^n2));
else if (s==">>")
Result.setText(printBin(n1>>n2));
else if (s=="<<")
Result.setText(printBin(n1<<n2));
else if (s==">>>")
Result.setText(printBin(n1>>>n2));
}
}
int getInt(String s)
{
int n1 = 0;
try
{
n1 = Integer.parseInt(s);
}
catch(Exception e)
{
Error.setText("Illegal integer #: " + s);
}
return n1;
}
String printBin(int x)
{
String result = "";int filter = 0x40000000;
try
{
if ((x & 0x80000000) == 0x80000000)//This is sign bit
result = result + "1";
else
result = result + "0";
for (int i=0; i < 31; i++)
{
if ((filter & x) == filter)
result = result + "1";
else
result = result + "0";
filter = filter >> 1;
}
}
catch(Exception e)
{
System.out.println("ERROR");
}
return result;
}
}public class Bin extends Frame {
public static void main(String[] arg) {
BinApp a = new BinApp();
a.setSize(250,200);
a.setVisible(true);
}
}
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import javax.xml.parsers.*;
import org.w3c.dom.*;
/**
* @author kishore
* Created on Nov 21, 2002
* Used for parsing elements & attributes
*/
public class XMLParserUtils {
/**
This method is used to get the value of the element.
The element should have only one text node, and no child elements.
Eg:
@params n = 'value' node
@return value = 'xxx' in the value element
*/
public static String getElementValue(Node n) {
String retVal = null;
Node textNode = n.getFirstChild();
if((textNode != null) && (textNode.getNodeType() == Node.TEXT_NODE)) {
retVal = textNode.getNodeValue();
}
return retVal;
}
/**
This method is used to get the value of the attribute in an element.
Eg:
@params n = 'value' node
@params attr = attribute name, 'id' in the above example
@return value = "abc" the attribute value of id in the value element
*/
public static String getAttributeValue(Node n, String attr) {
String retVal = null;
if(n.getNodeType() == Node.ELEMENT_NODE) {
retVal = ((Element)n).getAttribute(attr);
}
return retVal;
}
}
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import java.io.*;
import java.net.*;
/**
* @author kishore
* Created on Feb 20, 2003
*/
public class ReadContentsOfURL{
public static void main(String[] args) throws Exception
{
// create a URL object and open a stream to it
URL httpUrl = new URL("http://www.weather.com/weather/local/94539?lswe=94539");
InputStream istream = httpUrl.openStream();
// convert stream to a BufferedReader
InputStreamReader ir = new InputStreamReader(istream);
BufferedReader reader = new BufferedReader( ir );
// then read the contents of the URL through a BufferedReader
StringBuffer buf = new StringBuffer();
int nextChar;
while( (nextChar = reader.read()) != -1 )
{
buf.append( (char)nextChar );
}
// close the reader
reader.close();
System.out.println( buf );
}
}
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import java.io.IOException;
/**
* @author kishore
* Created on Feb 21, 2003
*/
// To start a process(Spawn a process within the jvm)
public class ProcessExec
{
public static void main( String[] argv )
{
String command = "c:\\winnt\\explorer.exe";
try
{
Process process = Runtime.getRuntime().exec( command );
}
catch ( IOException ioex )
{
ioex.printStackTrace();
}
}
}
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HidePasswordFromCommandLine.java
import java.io.*;
/**
* @author kishore
* Created on Feb 21, 2003
*/
public class HidePasswordFromCommandLine extends Thread {
boolean stopThread= false;
boolean hideInput= false;
boolean shortMomentGone= false;
public void run() {
try {
sleep(500);
} catch (InterruptedException e) {}
shortMomentGone= true;
while (!stopThread) {
if (hideInput) {
System.out.print("\b*");
}
try {
sleep(1);
} catch (InterruptedException e) {}
}
}
public static void main(String[] arguments) {
String name= "";
String password= "";
HidePasswordFromCommandLine hideThread= new HidePasswordFromCommandLine();
hideThread.start();
BufferedReader in= new BufferedReader(new InputStreamReader(System.in));
try {
System.out.println("Name: ");
// Wait for the username and clear the keyboard buffer (if neccessarry)
do {
name= in.readLine();
}
while (hideThread.shortMomentGone == false);
// Now the hide thread should begin to overwrite any input with "*"
hideThread.hideInput= true;
// Read the password
System.out.println("\nPassword:");
System.out.print(" ");
password = in.readLine();
hideThread.stopThread= true;
}
catch (Exception e) {}
System.out.print("\b \b");
// JUST FOR TESTING - PLEASE DELETE!
System.out.println("\n\nLogin= " + name);
System.out.println("Password= " + password);
}
}
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TTSTest.java
import java.io.File;
import java.util.Locale;
import javax.speech.Central;
import javax.speech.Engine;
import javax.speech.synthesis.Synthesizer;
import javax.speech.synthesis.SynthesizerModeDesc;
import javax.speech.synthesis.SynthesizerProperties;
import javax.speech.synthesis.Voice;
/**
* @author kishore
* Created on Dec 6, 2002
* Simple program showing how to use TTS in JSAPI.
*/
public class TTSTest {
public static void main(String[] argv) {
try {
String synthesizerName = System.getProperty
("synthesizerName",
"Unlimited domain FreeTTS Speech Synthesizer from Sun Labs");
// Create a new SynthesizerModeDesc that will match the TTS
// Synthesizer.
SynthesizerModeDesc desc = new SynthesizerModeDesc
(synthesizerName,
null,
Locale.US,
Boolean.FALSE, // running?
null); // voice
Synthesizer synthesizer = Central.createSynthesizer(desc);
if (synthesizer == null) {
String message = "Can't find synthesizer.\n" +
"Make sure that there is a \"speech.properties\" file " +
"at either of these locations: \n";
message += "user.home : " +
System.getProperty("user.home") + "\n";
message += "java.home/lib: " + System.getProperty("java.home")
+ File.separator + "lib\n";
System.err.println(message);
System.exit(1);
}
// create the voice
String voiceName = System.getProperty("voiceName", "kevin16");
Voice voice = new Voice
(voiceName, Voice.GENDER_DONT_CARE, Voice.AGE_DONT_CARE, null);
// get it ready to speak
synthesizer.allocate();
synthesizer.resume();
synthesizer.getSynthesizerProperties().setVoice(voice);
// speak the "Hello Kishore" string
synthesizer.speakPlainText("Hello Kishore", null);
// wait till speaking is done
synthesizer.waitEngineState(Synthesizer.QUEUE_EMPTY);
// clean up
synthesizer.deallocate();
}
catch (Exception e) {
e.printStackTrace();
}
System.exit(0);
}
}
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BasicDateFormatting.java
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
/**
* @author kishore
* Created on Feb 21, 2003
*/
public class BasicDateFormatting
{
public static void main(String[] args) throws Exception
{
// get today's date
Date today = Calendar.getInstance().getTime();
// create a short version date formatter
DateFormat shortFormatter
= SimpleDateFormat.getDateInstance( SimpleDateFormat.SHORT );
// create a long version date formatter
DateFormat longFormatter
= SimpleDateFormat.getDateInstance( SimpleDateFormat.LONG );
// create date time formatter, medium for day, long for time
DateFormat mediumFormatter
= SimpleDateFormat.getDateTimeInstance( SimpleDateFormat.MEDIUM,
SimpleDateFormat.LONG );
// use the formatters to output the dates
System.out.println( shortFormatter.format( today ) );
System.out.println( longFormatter.format( today ) );
System.out.println( mediumFormatter.format( today ) );
// convert form date -> text, and text -> date
String dateAsText = shortFormatter.format( today );
Date textAsDate = shortFormatter.parse( dateAsText );
System.out.println( textAsDate );
}
}
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Whoami.java
/**
* @author kishore
* Created on Feb 14, 2003
*/
import java.io.*;
import java.net.*;
public class Whoami
{
/**
* Tells you the domain name and IP of the machine
* you are running.
* @author kishore
* Created on Dec 6, 2002 *
* @param args not used.
*/
public static void main (String[] args)
{
try
{
InetAddress localaddr = InetAddress.getLocalHost () ;
System.out.println ( "main Local IP Address : " + localaddr.getHostAddress () );
System.out.println ( "main Local hostname : " + localaddr.getHostName () );
System.out.println ( "main Domain name : " + localaddr.getCanonicalHostName());
System.out.println () ;
InetAddress[] localaddrs = InetAddress.getAllByName ( "localhost" ) ;
for ( int i=0 ; i
if ( ! localaddrs[ i ].equals( localaddr ) )
{
System.out.println ( "alt Local IP Address : " + localaddrs[ i].getHostAddress () );
System.out.println ( "alt Local hostname : " + localaddrs[ i].getHostName () );
System.out.println () ;
}
}
}
catch ( UnknownHostException e )
{
System.err.println ( "Can't detect localhost : " + e) ;
}
}
}
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