If == compares references in Java, why does it evaluate to true with these Strings?

Question

As it is stated the == operator compares object references to check if they are referring to the same object on a heap. If so why am I getting the \"Equal\" for this piece o

Answer 1

The program will print Equal. (At least using the Sun Hotspot and suns Javac.) Here it is demonstrated on http://ideone.com/8UrRrk

This is due to the fact that string-literal constants are stored in a string pool and string references may be reused.

Further reading:

• What is String literal pool?
• String interning

---

This however:

public class Salmon {
    public static void main(String[] args) {

        String str1 = "Str1";
        String str2 = new String("Str1");

        if (str1 == str2) {
            System.out.println("Equal");
        } else {
            System.out.println("Not equal");
        }
    }
}

Will print Not equal since new is guaranteed to introduce a fresh reference.

So, rule of thumb: Always compare strings using the equals method.