How is StringBuffer implementing append function without creating two objects?

Question

It was an interview question. I was asked to implement the StringBuffer append function. I saw the code after the interview. But I cannot understand how the operati

Answer 1

****String s1="Azad"; ----One object will create in String cons. pool

System.out.println(s1);--output--Azad

s1=s1.concat("Raja");  Two object will create 1-Raja,2-AzadRaja and address of AzadRaja Store in reference s1 and cancel ref.of Azad object 

System.out.println(s1);  --output AzadRaja****