Java Integer Behaviour magic or bug? (not it's not bug) or you can give a name .... But it's a fine manage of JAVA architACT

JavaIntegerBehave.java

public class JavaIntegerBehave  {
  
  public static void main(String[] args) {
	  Integer i= new Integer(10);
  	Integer j= new Integer(10);
  	System.out.println("R1: "+(i==j));   // false
  	    
  	    
  	Integer k= 10;//new Integer(10);
  	Integer l = 10;//new Integer(10);
  	System.out.println("R2: "+(k==l));   // true ---- WHY ?
  	
  	Integer m= new Integer(1000);
  	Integer n= new Integer(1000);
  	System.out.println("R3: "+(m==n));  // false	
  	    
  	Integer o= 1000;//new Integer(1000);
  	Integer p= 1000;//new Integer(1000);
  	System.out.println("R4: "+(o==p));	   //false ---- WHY ?
  
  	System.out.println("");       
  	System.out.println("Actually the case happen upto 127 I found By Print");       
  	System.out.println("SPECIAL_CASE_127");   
  	Integer s= new Integer(127);
  	Integer t= new Integer(127);
  	System.out.println("SR1_127: "+(s==t));   // false
  
  	Integer u= 127;//new Integer(127);
  	Integer v= 127;//new Integer(127);
  	System.out.println("SR2_127: "+(u==v));   // true
  	
  	
  	System.out.println("SPECIAL_CASE_128");   
  	Integer w= new Integer(128);
  	Integer x= new Integer(128);
  	System.out.println("SR1_128: "+(w==x));   // false
  
  	Integer y= 128;//new Integer(128);
  	Integer z= 128;//new Integer(128);
  	System.out.println("SR2_128: "+(y==z));   // false
  
  	System.out.println("");    
  	System.out.println("ANOTHER_MAGIC_MAIRALA");  
  	Integer f= new Integer(10);
  	Integer g= new Integer(10);
  	System.out.println("MR1:: F: "+f+" G: "+g); 
  	System.out.println("MR1: "+(f==g));   // false ... OK IT IS FALSE BUT ??
  	f++;
  	g++;
  	System.out.println("MR2:: F: "+f+" G: "+g);
  	System.out.println("MR1: "+(f==g));   // true (how??)... CAN YOU IMAGINE ?? but it Created By new operator
  	/*
  	R1: false
  	R2: true
  	R3: false
  	R4: false
  
  	Actually the case happen upto 127 I found By Print
  	SPECIAL_CASE_127
  	SR1_127: false
  	SR2_127: true
  	SPECIAL_CASE_128
  	SR1_128: false
  	SR2_128: false
  
  	ANOTHER_MAGIC_MAIRALA
  	MR1:: F: 10 G: 10
  	MR1: false
  	MR2:: F: 11 G: 11
  	MR1: true
  	*/
  	
  	// I got all these facts happen because of  [ IntegerCache private static class ] in Integer.java file
  }

}