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Threading

Threading:-Thread is a public class in java which internally implements Runnable interface, Runnable interface having only one method that is run method. Purpose of thread class and Runnable interface is to achieve multitasking programming, in a normal programming we know the flow of program execution because normal methods execute sequentially and this sequence is possible through stack all the processes run in a common stack.
Thread is a lightweight process which is run in separate stack space, so all the threads run in separate stack space simultaneously that’s why threads run independently. If in a program more than one thread executing this process called multi threading. Order of execution of threads are depends on thread scheduler.
In short multi threading is many thread objects want to execute same piece of code for example many people online book tickets here peoples are thread object and tickets are that piece of code which is written in run() method.

Threading is achieved by two ways in a programming.
1) by extending Thread class.
2) by implementing Runnable interface

Example1:- TestThread.java

class TestThread extends Thread
{
public static void main(String[]args)
{
TestThread t1=new TestThread();
t1.start();
}
public void run()
{
for(int i=1;i<=10;i++)
{
System.out.println(i);
}
}
}
Output:-
C:\JAVATECH>javac TestThread.java
C:\JAVATECH>java TestThread
12345678910

Example2:- TestThread.java

class TestThread extends Thread
{
public static void main(String[]args)
{
TestThread t1=new TestThread();
System.out.println(t1);
t1.start();
}
public void run()
{
for(int i=1;i<=10;i++)
{
System.out.print(i);
}
}
}
Output:-
C:\JAVATECH>javac TestThread.java
C:\JAVATECH>java TestThread
Thread[Thread-0,5,main]
12345678910

Example3:- TestThread.java

class TestThread extends Thread
{
public static void main(String[]args)
{
TestThread t1=new TestThread();
t1.setName("Amit");
System.out.println(t1);
t1.start();
}
public void run()
{
for(int i=1;i<=10;i++)
{
System.out.print(i);
}
}
}
Output:-
C:\JAVATECH>javac TestThread.java
C:\JAVATECH>java TestThread
Thread[Amit,5,main]
12345678910

Example4:- TestThread.java

class TestThread extends Thread
{
public static void main(String[]args)
{
TestThread t1=new TestThread();
t1.setPriority(1);    //range of priority is b/w 1 to 10
t1.setName("Amit");
System.out.println(t1);
t1.start();
}
public void run()
{
for(int i=1;i<=10;i++)
{
System.out.print(i);
}
}}
Output:-
C:\JAVATECH>javac TestThread.java
C:\JAVATECH>java TestThread
Thread[Amit,1,main]
12345678910

Example5:- TestThread.java

class TestThread extends Thread
{
public static void main(String[]args)
{
TestThread t1=new TestThread();
t1.setName("Amit");
TestThread t2=new TestThread();
t2.setName("Sumit");
t1.start();
t2.start();
}
public void run()
{
for(int i=1;i<=5;i++)
{
System.out.print(i);
}}}
Output:-
C:\JAVATECH>javac TestThread.java
C:\JAVATECH>java TestThread
1234512345

Example6:- TestThread.java

class TestThread extends Thread
{
public static void main(String[]args)
{
TestThread t1=new TestThread();
t1.setName("Amit");
TestThread t2=new TestThread();
t2.setName("Sumit");
t1.start();
t2.start();
}
public void run()
{
for(int i=1;i<=5;i++)
{
try
{
Thread.sleep(1500);
}catch(Exception e){}
System.out.println("by "+Thread.currentThread().getName()+" i= "+i);
}}}
Output:-
C:\JAVATECH>javac TestThread.java
C:\JAVATECH>java TestThread
by Sumit i= 1
by Amit i= 1
by Sumit i= 2
by Amit i= 2
by Amit i= 3
by Sumit i= 3
by Amit i= 4
by Sumit i= 4
by Amit i= 5
by Sumit i= 5

Example7:- TestThread.java

class TestThread implements Runnable
{
int AVT=1,Req;
TestThread(int Req)
{
this.Req=Req;
}
public static void main(String[]args)
{
TestThread t=new TestThread(1);
Thread t1=new Thread(t);
Thread t2=new Thread(t);
t1.setName("Amit");
t2.setName("Sumit");
t1.start();
t2.start();
}
 public void run()
{
if(AVT>=Req)
{
System.out.println("Well-come "+Thread.currentThread().getName());
try
{
Thread.sleep(1500);
}catch(Exception e){}
AVT=AVT-Req;
System.out.println(Req +"Ticket is allocated to "+Thread.currentThread().getName());
}
else
{
System.out.println("Sorry ticket not available");
}}}
Output:-
C:\JAVATECH>javac TestThread.java
C:\JAVATECH>java TestThread
Well-come Amit
Well-come Sumit
1Ticket is allocated to Sumit
1Ticket is allocated to Amit

Example8:- TestThread.java

class TestThread implements Runnable
{
int AVT=1,Req;
TestThread(int Req)
{
this.Req=Req;
}
public static void main(String[]args)
{
TestThread t=new TestThread(1);
Thread t1=new Thread(t);
Thread t2=new Thread(t);
t1.setName("Amit");
t2.setName("Sumit");
t1.start();
t2.start();
}
 synchronized public void run()
{
if(AVT>=Req)
{
System.out.println("Well-come "+Thread.currentThread().getName());
try
{
Thread.sleep(1500);
}catch(Exception e){}
AVT=AVT-Req;
System.out.println(Req +"Ticket is allocated to "+Thread.currentThread().getName());
}
else
{
System.out.println("Sorry ticket not available");
}}}
Output:-
C:\JAVATECH>javac TestThread.java
C:\JAVATECH>java TestThread
Well-come Amit
1Ticket is allocated to Amit
Sorry ticket not available

Example9:- TestThread.java

class TestThread implements Runnable
{
int AVT=1,Req;
TestThread(int Req)
{
this.Req=Req;
}
public static void main(String[]args)
{
TestThread t=new TestThread(1);
Thread t1=new Thread(t);
Thread t2=new Thread(t);
t1.setName("Amit");
t2.setName("Sumit");
t1.start();
t2.start();
}
public void run()
{
System.out.println("Well-come "+Thread.currentThread().getName());
synchronized(this)
{
if(AVT>=Req)
{
try
{
Thread.sleep(1500);
}catch(Exception e){}
AVT=AVT-Req;
System.out.println(Req +"Ticket is allocated to "+Thread.currentThread().getName());
}
else{
System.out.println("Sorry ticket not available");
}}}}
Output:-
C:\JAVATECH>javac TestThread.java
C:\JAVATECH>java TestThread
Well-come Amit
Well-come Sumit
1Ticket is allocated to Amit
Sorry ticket not available

Example10:-TestThread.java

class TestThread implements Runnable
{
public static void main(String[]args)
{
TestThread t1=new TestThread();
Thread t2=new Thread(t1);
t2.setName("Amit");
TestThread t3=new TestThread();
Thread t4=new Thread(t3);
t4.setName("Sumit");
t4.start();
t2.start();
}
public void run()
{
for(int i=1;i<=5;i++)
{
try
{
Thread.sleep(1500);
}catch(Exception e){}
System.out.println("by "+Thread.currentThread().getName()+" i= "+i);}}}
Output:-
C:\JAVATECH>javac TestThread.java
C:\JAVATECH>java TestThread
by Sumit i= 1
by Amit i= 1
by Sumit i= 2
by Amit i= 2
by Sumit i= 3
by Amit i= 3
by Amit i= 4
by Sumit i= 4
by Sumit i= 5
by Amit i= 5


Example11:-Chat.java (Thread communication)
import java.util.*;
class Chat implements Runnable
{
String s="start";
Scanner sc=new Scanner(System.in);
synchronized void chatGarima()
{
while(!(s.equals("stop")))
{
if((s.equals("start")))
{
try
{
wait();
}
catch(Exception e)
{

}
}
System.out.println(Thread.currentThread().getName()+":"+s);
System.out.println(Thread.currentThread().getName()+":");
s=sc.nextLine();
notify();
try
{
wait();
}
catch(Exception e)
{

}
}
}
synchronized void chatRadha()
{
while(!(s.equals("stop")))
{
if((s.equals("start")))
{
System.out.println(Thread.currentThread().getName()+":");
s=sc.nextLine();
notify();
try
{
wait();
}
catch(Exception e)
{

}
}
System.out.println(Thread.currentThread().getName()+":"+s);
System.out.println(Thread.currentThread().getName()+":");
s=sc.nextLine();
notify();
try
{
wait();
}
catch(Exception e)
{

}
}
}

public void run()
{
if(Thread.currentThread().getName().equals("Garima"))
{
chatGarima();
}
else
{
chatRadha();
}

}

public static void main(String[]args)
{
Chat ct=new Chat();
Thread t1=new Thread(ct,"Garima");
Thread t2=new Thread(ct,"Radha");

t2.start();
t1.start();
}
}
Output:-
C:\JAVATECH>javac Chat.java
C:\JAVATECH>java Chat
Radha:
hello Garima
Garima:hello Garima
Garima:
hi Radha
Radha:hi Radha
Radha:
how r u
Garima:how r u
Garima:
i m fine
Radha:i m fine

Radha:

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