String Comparison

String Comparison

1. Three Ways (beginner must-master!)

== (addresses — WRONG for content!), .equals() (content — CORRECT!), compareTo() (ordering: dictionary rank).

2. Code — The Proof (run this once, remember forever!)

String a = new String("hi");
String b = new String("hi");
System.out.println(a == b);       // false (different houses!)
System.out.println(a.equals(b));  // true (same furniture!)
System.out.println("apple".compareTo("banana")); // negative (a < b)
System.out.println("hi".compareTo("hi"));        // 0 (equal!)
System.out.println("b".compareTo("a"));          // positive (b > a)
System.out.println("Hi".equalsIgnoreCase("hi")); // true (case ignored!)

Method	Compares	Returns
==	addresses	true only if same object!
.equals()	content	true if same letters
compareTo()	dictionary order	0 equal, <0 before, >0 after
equalsIgnoreCase()	content, no case	true for Hi/hi

3. Traps (exam's favourite trap of all time!)

• new String("hi") == new String("hi") is false (two houses!). Always .equals() for content.
• Literals "hi" == "hi" is true (pool accident — shared!). Don't rely on it!
• compareTo is case-sensitive: "A" (65) < "a" (97).

4. Exam Points

• == vs .equals() vs compareTo with output — 7 marks, all-time favourite.
• Login check with .equals() — 3 marks, frequent.