How many String objects ?

String s1 = "abc";

// Creates 1 obj in String pool (s1 will refer to object in String pool)

String s2 = new String("xyz");

// Creates 2 new objects, one in String pool and one in heap (s2 will point to object on heap)

s2=s1;

// No new object is created; only assignment will take place

s1.toUpperCase();

// Creates 1 obj

String s3 = "abc";

// No object created (s3 points to existing object in String Pool)

String s4 = s3.replace('a','A');

// Creates 1 new object

Total objects created : 5