String Comparison

[Vikram Ramaswamy]

Hi, sorry if this is a lame question that I already ought to know (or has already been answered)
Given Strings s1 and s2, I was wondering what the real difference between s1 == s2 and s1.equals(s2) is

public class StringEqualsTest {
    public static void main(String[] args) {
	String s1 = "Hello World";
	String s2 = "Hello World";
	String s3 = "Below Borls";
	
	if ( s1 == s2 ) {
	    System.out.println("s1 == s2");
	}
	if ( s1.equals(s2) ) {
	    System.out.println(s1+ " equals " +s2);
	}
    
    System.out.println("s1 hashcode = "+s1.hashCode());
    System.out.println("s2 hashcode = "+s2.hashCode());
    }
}
   
    

In my understanding, s1 == s2 must fail since they are two separate objects, but when I run the code, both if conditions pass & Hash codes are equal too...

[Balu Sadhasivam]

In my understanding, s1 == s2 must fail since they are two separate objects,

NO they are 2 references to *same* String literal in String Constant Pool.

check Javaranch Journal.

[Vikram Ramaswamy]

I got it now. Thank you.

[Balu Sadhasivam]

you are Welcome. and Indeed Welcome to Javaranch

[Rene Larsen]

If you want to do the same check with Integer, Byte or Long - you will see that there are a Constant Pool limit of values in the range -128 to 127

Meaning the == will only work in the range -128 to 127

[Muhammad Khojaye]

Rene Larsen wrote:Meaning the == will only work in the range -128 to 127

integers not being equal to one another