Program : To demonstrate the concept of synchronization.

Algorithm

Step 1: Start.
Step 2: Create class bank.
Step 3: Boolean recvd=false,int bal=600,int amt=0,int wamt=0.
Step 4: Create class d implements Runnable.
Step 5: Create class w implements Runnable.
Step 6: new d(b).
Step 7: new w(b).
Step 8: Stop.
Function synchronized void withdraw()

Step 1: Start.
Step 2: if(!recvd) go to 3 else to 4..
Step 3: wait().
Step 4: Read wamt.
Step 5: if(wamt>bal) go to 6 else to 7..
Step 6: Print “Not enough money in your account-your current balance is”,bal
goto 11.
Step 7: if(wamt>1&&wamt1&&amt2000) go to 11 else to 13.
Step 11: recvd=true.
Step 12: notify().
Step 13: Exit.

Constructor d(bank b)

Step 1: Start.
Step 2: this.b=b..
Step 3: new Thread(this,”deposit”).start().
Step 4: Exit.

Function public void run() of class d

Step 1: Start.
Step 2: Repeat step 3 until true.
Step 3: b.deposit().
Step 4: Exit.

Constructor w(bank b)

Step 1: Start.
Step 2: this.b=b..
Step 3: new Thread(this,”withdraw”).start().
Step 4: Exit.

Function public void run() of class w

Step 1: Start.
Step 2: Repeat step 3 until true.
Step 3: b.withdraw().
Step 4: Exit.

Program

import java.io.*;
import java.lang.*;

class Bank 
{
	String msg;
	boolean recvd=false;
	int bal;
	int amt;
	int wamt;
	Bank()
	{
		bal=600;
		amt=0;
		wamt=0;
	}
	synchronized  void withdraw()
	{
		if(!recvd)
			try
			{
				wait();
			}
			catch(Exception e)
			{
				System.out.println("Error : " + e );	
			}
		
		try
		{
			InputStreamReader in=new InputStreamReader(System.in);
			BufferedReader b=new BufferedReader(in);
			System.out.println("Type withdrawal amount");
			wamt=Integer.parseInt(b.readLine());
			if(wamt>bal)
			{
System.out.println("Not enough money in your A/c:-Your current balance is "+bal);
			}
			else
			{
				if(wamt>1&&wamt1&&amt2000)
		{
			recvd=true;
			notify();
		}
	}
}		

class d implements Runnable
{
   	Bank b;
   	d(Bank b)
    	{
    		this.b=b;
    		new Thread(this,"deposit").start();	
    	} 
    
   	public void run()
    	{
    		while(true)
    		{
    			b.deposit();
    		}
    	} 		
}

class w implements Runnable
{
   	Bank b;
    	w(Bank b)
    	{
    		this.b=b;
    		new Thread(this,"withdraw").start();	
   	} 
    	public void run()
    	{
    		while(true)
    		{
    		b.withdraw();
    		}
    	} 		
}
 
public  class MyBank
{
   	public static void main(String args[])
   	{
   		Bank b=new Bank();
   		new d(b);
   		new w(b);	
   	}
}

Output

Balance less than 2000
Press Ctrl+b to terminate
Type amount to be deposited
500
Type an amount between 1 and 200
Balance less than 2000
Press Ctrl+b to terminate
Type amount to be deposited
200
Type an amount between 1 and 200
Balance less than 2000
Press Ctrl+b to terminate
Type amount to be deposited
150
Your current balance (d) is 750
Balance less than 2000
Press Ctrl+b to terminate
Type amount to be deposited
150
Your current balance (d) is 900
Balance less than 2000
Press Ctrl+b to terminate
Type amount to be deposited
150
Your current balance (d) is 1050
Balance less than 2000
Press Ctrl+b to terminate
Type amount to be deposited
150
Your current balance (d) is 1200
Balance less than 2000
Press Ctrl+b to terminate
Type amount to be deposited
150
Your current balance (d) is 1350
Balance less than 2000
Press Ctrl+b to terminate
Type amount to be deposited
150
Your current balance (d) is 1500
Balance less than 2000
Press Ctrl+b to terminate
Type amount to be deposited
150
Your current balance (d) is 1650
Balance less than 2000
Press Ctrl+b to terminate
Type amount to be deposited
150
Your current balance (d) is 1800
Balance less than 2000
Press Ctrl+b to terminate
Type amount to be deposited
150
Your current balance (d) is 1950
Balance less than 2000
Press Ctrl+b to terminate
Type amount to be deposited
150
Your current balance (d) is 2100
Type withdrawal amount
200
Type an amount between 1 and 150
Type withdrawal amount
100
Your current balance (w) is 2000
Type withdrawal amount
100
Your current balance (w) is 1900
Type withdrawal amount
150
Type an amount between 1 and 150
Type withdrawal amount
125
Your current balance (w)is 1775
Type withdrawal amount

Multithreading and Synchronization in Java is a post from ShoutToWorld - Let's Learn Let's Shout - Helping bloggers and developers.