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  1. import java.util.*;
  2. import java.lang.*;
  3.  
  4. class Main
  5. {
  6.     public static abstract class AbstractClass {
  7.         private String id;
  8.  
  9.         AbstractClass( String id0 ) { id = id0; }
  10.  
  11.         public boolean equals(Object other) {
  12.             return other != null && other.getClass().equals(getClass())
  13.                     && id.equals(((AbstractClass) other).id);
  14.         }
  15.  
  16.     }
  17.  
  18.     public static class ConcreteClassOne extends AbstractClass
  19.     {
  20.   private final AbstractClass parent;
  21.  
  22.   public ConcreteClassOne( String anId, AbstractClass aParent )
  23.   {
  24.     super( anId );
  25.  
  26.     parent = aParent;
  27.   }
  28. }
  29.  
  30. public static class ConcreteClassTwo extends ConcreteClassOne
  31. {
  32.   private static int nextTrackingNo = 0;
  33.  
  34.   private final int trackingNo;
  35.  
  36.   public ConcreteClassTwo ( String anId )
  37.   {
  38.     super( anId, null );
  39.  
  40.     trackingNo= getNextTrackingNo();
  41.   }
  42.  
  43.     public boolean equals(Object other) {
  44.         boolean rv = super.equals( other );
  45.         if ( other instanceof ConcreteClassTwo ) {
  46.            rv = rv && (this.trackingNo == ((ConcreteClassTwo) other).trackingNo);
  47.         }
  48.         return rv;
  49.     }
  50.  
  51.     private int getNextTrackingNo() {
  52.          return nextTrackingNo++;
  53.     }
  54. }    
  55.  
  56.  
  57. 	public static void main (String[] args) throws java.lang.Exception
  58. 	{
  59.         ConcreteClassTwo c2a = new ConcreteClassTwo( "one" );
  60.         ConcreteClassTwo c2b = new ConcreteClassTwo( "one" );
  61.         ConcreteClassOne c1  = new ConcreteClassOne( "one", null );
  62.  
  63.         System.out.println( c2a.equals( c1 ));
  64.         System.out.println( c1.equals( c2b ));
  65.         System.out.println( c2a.equals( c2b ));
  66. 	}
  67. }
Success #stdin #stdout 0.06s 380224KB
comments (?)
stdin 
Standard input is empty
stdout 
false
false
false
https://ideone.com/3yMrU8
language:
Java (HotSpot 12)
created:
12 years ago
visibility:
public

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