String StringBuffer
Immutable Mutable
String s=new String("karthik"); StringBuffer sb=new StringBuffer("karthik")
s.concat("reddy"); sb.append("reddy");
System.out.println(s); System.out.println(sb);
O/P:karthik O/P:karthikreddy
--->once we created a String object ---->once we created a StringBuffer object
we can't perform any changes in the existing we can perform any changes in the existing
object.If we are trying to perform any object.It is nothing but mutablity of
changes with those changes a new object of a StrongBuffer object
will be created.It is nothing but Immutability
of a String object
Use String--->If you require immutabilty
Use StringBuffer---->If you require mutable + threadsafety
Use StringBuilder--->If you require mutable + with out threadsafety
String s=new String("karthik");
--->here 2 objects will be created one is heap and the other is in stringconstantpool(scp) and s is always pointing to heap object
String s="karthik";
--->In this case only one object will be created in scp and s is always pointing to that object only