cara memeriksa string duplikat di java

String first = "Hello";
String second = "hELLo";

if(first.equal(second)) { 
	// Check if first string is equal to second string. lower/upper case matter.
}

if(first.equalsIgnoreCase(second)) {
	// Check if first string is equal to second string. lower/upper does not matter.
}
Bredo