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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8.  
  9. class MyClass
  10. {
  11. 	public static int count=0;
  12.  
  13. 	static boolean lock=false;
  14.  
  15. 	boolean getLock()
  16. 	{
  17. 		synchronized(this)
  18. 		{
  19. 			if(lock==false)
  20. 			{
  21. 				lock=true;
  22. 				return true;
  23. 			}
  24. 			else
  25. 			{
  26. 				return false;
  27. 			}
  28. 		}
  29. 	}
  30.  
  31.  
  32.      public  int getCount() 
  33.      {
  34.  
  35.     	System.out.println("Inside getcount()");
  36.  
  37.  
  38.     		 return count;
  39.  
  40.  
  41.     }
  42.  
  43.  
  44.     public synchronized void incrementCount() 
  45.     {
  46.  
  47.        	count=count+1;
  48.  
  49.     }
  50.  
  51.     public synchronized void decrementCount() 
  52.     {
  53.  
  54.        	count=count-1;
  55.  
  56.     }
  57. }
  58.  
  59. class Ideone
  60. {
  61.  
  62.  	public static int count=0;
  63.  
  64. 	static boolean lock=false;
  65.  
  66. 	boolean getLock()
  67. 	{
  68. 		synchronized(this)
  69. 		{
  70. 			if(lock==false)
  71. 			{
  72. 				lock=true;
  73. 				return true;
  74. 			}
  75. 			else
  76. 			{
  77. 				return false;
  78. 			}
  79. 		}
  80. 	}
  81.  
  82.  
  83.      public  int getCount() 
  84.      {
  85.  
  86.     	System.out.println("Inside getcount()");
  87.  
  88.  
  89.     		 return count;
  90.  
  91.  
  92.     }
  93.  
  94.  
  95.     public synchronized void incrementCount() 
  96.     {
  97.        int x=count+1;
  98.  
  99.        	try {
  100.  
  101.         Thread.sleep((int) (100 + (Math.random() * (400 - 5))));
  102.     } catch (InterruptedException e) {
  103.         e.printStackTrace();
  104.     }
  105.     count= x;
  106.  
  107.     }
  108.  
  109.     public synchronized void decrementCount() 
  110.     {
  111.  
  112.        	count=count-1;
  113.  
  114.     }
  115.  
  116.  
  117.     public static void main(String[] args) throws InterruptedException {
  118.         final MyClass test1 = new MyClass();
  119.         final MyClass test2 = new MyClass();
  120.         final MyClass test3 = new MyClass();
  121.         final MyClass test4 = new MyClass();
  122.         Thread t1 = new Thread() { 
  123.         							public void run()  
  124.         							{ 
  125.         								int k=0;
  126.         								while (k++<5000000)
  127.         								{
  128.         									//System.out.println("Thread 1 going to increment count");
  129.         									test1.incrementCount();
  130.         									//System.out.println("Thread 1 incremented  count");
  131.         								} 
  132.         							}
  133.         							};
  134.  
  135.         Thread t2 = new Thread() { 
  136.         							public void run() 
  137.         							{ 
  138.         								int l=0;
  139.         								while (l++<5000000)
  140.         								{
  141.         									//System.out.println("Thread 1 going to increment count");
  142.         										test2.incrementCount(); 
  143.         									//System.out.println("Thread 2 count read = " + c);
  144.         								} 
  145.         							}
  146.         							};
  147.         Thread t3 = new Thread() { 
  148.         							public void run() 
  149.         							{ 
  150.         								int l=0;
  151.         								while (l++<5000000)
  152.         								{
  153.         									//System.out.println("Thread 1 going to increment count");
  154.         										test3.incrementCount(); 
  155.         									//System.out.println("Thread 2 count read = " + c);
  156.         								} 
  157.         							}
  158.         							};      
  159.         Thread t4 = new Thread() { 
  160.         							public void run() 
  161.         							{ 
  162.         								int l=0;
  163.         								while (l++<5000000)
  164.         								{
  165.         									//System.out.println("Thread 1 going to increment count");
  166.         										test4.incrementCount(); 
  167.         									//System.out.println("Thread 2 count read = " + c);
  168.         								} 
  169.         							}
  170.         							};   
  171.        // Thread t2 = new Thread() { public void run() { test1.testMethod2(); } };
  172.         t1.start();
  173.  
  174.         t2.start();
  175.         t3.start();
  176.         t4.start();
  177.        	t1.join();
  178.        	t2.join();
  179.        	t3.join();
  180.        	t4.join();
  181.         //System.out.println(t2.getState());
  182.         //int x=500000000+500000000;
  183.         //System.out.println(x);
  184.         System.out.println("count = " + MyClass.count);
  185.  
  186.     }
  187. }
  188.  
  189.  
Success #stdin #stdout 0.59s 381504KB
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count = 20000000
https://ideone.com/wo6h4R
language:
Java (HotSpot 12)
created:
9 years ago
visibility:
secret

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