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What will be the output of the program? String a = "ABCD"; String b = a.toLowerCase(); b.replace('a','d'); b.replace('b','c'); System.out.println(b);

abcd
ABCD
dccd
dcba

Correct Answer: abcd

Explanation:

String objects are immutable, they cannot be changed, in this case we are talking about the replace method which returns a new String object resulting from replacing all occurrences of oldChar in this string with newChar.

b.replace(char oldChar, char newChar);

But since this is only a temporary String it must either be put to use straight away i.e.

System.out.println(b.replace('a','d'));

Or a new variable must be assigned its value i.e.

String c = b.replace('a','d');

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