Question

String a = "abc";
String b = "xyz";
String result = a + b;

I was wondering if “result” string is a String constant allocated memory in string pool or a new object created on heap.

I know that new String() creates object on heap and String constants like a,b in the above example in permgen string pool space.

Answer 1

An important note:

String a = "abc";
String b = "xyz";
String result = a + b;

is the same as

// creates a number of objects.
String result = new StringBuilder().append(a).append(b).toString();

but

final String a = "abc";
final String b = "xyz";
String result = a + b;

is the same as

String result = "abcxyz"; // creates no new objects.