Question

public class Test {
    int multiple;
    public static void main(String[] args){

        String string1 = "string";
        String string2 = "string";
        String string4 = "Changed";

        String string3 = new String("string");

        System.out.println("string1 == string2: " + (string1 == string2));\\true
        System.out.println("string1 == string4: " + (string1 == string4));\\false
        System.out.println("string1 == string3: " + (string1 == string3));\\false

    }


}

I understand that the == operator will return true if the references are same. What I want to know is, Does Java check the content of string literals before creating their objects?

Answer 1

It is the compiler that does the string interning. So at compile time identical strings are optimised. So I think the answer you want is “no”. The Virtual Machine doesn’t do it, it is the compiler. You can call String.intern() to acquire the shared string object in the string pool:

String str1 = "string";
String str2 = new String("string");
String str3 = str2.intern();

str1 == str2 // false
str2 == str3 // false
str1 == str3 // true

Strings, build at runtime are not interned automatically.