String manipulation

[Shrinath M Aithal]

What is the output of the following 
   StringBuffer sb1 = new StringBuffer("Amit"); 
   StringBuffer sb2= new StringBuffer("Amit"); 
   String ss1 = "Amit"; 
   System.out.println(sb1==sb2); 
   System.out.println(sb1.equals(sb2)); 
   System.out.println(sb1.equals(ss1)); 
   System.out.println("Poddar".substring(3));
 

i found it in mock test

could someone explain how it works? and why is it so?

[Bob Wheeler]

  
		   StringBuffer sb1 = new StringBuffer("Amit"); 
		   StringBuffer sb2= new StringBuffer("Amit"); 
		   String ss1 = "Amit"; 
		   System.out.println(sb1==sb2); // different objects - false
		   System.out.println(sb1.equals(sb2)); // StringBuffer inherits equals method from Object class - false
		   System.out.println(sb1.equals(ss1)); // StringBuffer inherits equals method from Object class - false
		   System.out.println("Poddar".substring(3)); // substring is returned; index starts by zero - "dar"
  

[Shrinath M Aithal]

??? why is sb1.equals(sb2) false?

[Madhu Desai]

Bob Wheeler wrote:

System.out.println(sb1.equals(sb2)); // StringBuffer inherits equals method from Object class - false 

Then, how to check the values between two StringBuffers are equal?

[Bob Wheeler]

Madhu Desai wrote:

Bob Wheeler wrote:

System.out.println(sb1.equals(sb2)); // StringBuffer inherits equals method from Object class - false 

Then, how to check the values between two StringBuffers are equal?

Use the StringBuffer.toString() method and equals on base on the String class equals-method. This would be my proposal:

 System.out.println(sb1.toString().equals(sb2.toString());  // sb1 and sb2 instanceOff StringBuffer 

StringBuffer is final, so you can't sublclass it and create your own equals method.

cheers
Bob

[Madhu Desai]

Bob Wheeler wrote:
StringBuffer is final, so you can't sublclass it and create your own equals method.

cheers
Bob

Thanks...