Question

I agree with the fact that the String objects are immutable, means they cannot be modified. Like in the case below

String str = "Hi";
String str1 = str.concat("Nilesh");

Here the str object will be returned if the length argument is 0 or a new String object will be created and its reference will be returned.
And if i do

String str = "Hi";
str="Hello";

How is it getting changed? where does immutable comes into picture? An example please.

Answer 1

What is immutable is the String itself, not the reference that points to the String. In your second code:

String str = "hi";
str = "hello";

There are 2 String objects involved: "hi" and "hello".

str is a reference that originally points to the first one then points to the second one following an assignment. But the String object "hi" does not get modified in that code.