equals() is a method that compares the actual content of the object.

"==" is an operator that compares the memory or reference location of an object in the heap.

equals()

• The String equals() function compares two strings based on their data/content. It is defined in java.lang package.

• It returns true if all of the contents of both strings match. It returns false if none of the characters match.

public class Hello {
   public static void main(String []args) {
      String s1 = "Welcome";
      String s2 = "Welcome";
      String s3 = new String ("welcome");
      System.out.println(s1.equals(s2));
      System.out.println(s2.equals(s3));
   }
}

Output:

true
false

"==" operator

• "==" checks if both objects point to the same memory location.

• Just like equals() method, "==" also returns a boolean output. Since "==" is an operator, it is not overrideable, and hence we avoid using it for comparing two objects.

class Hello {
    public static void main(String[] args)
    {
        System.out.println(10 == 20); //int type
        System.out.println('a' == 'b'); //char type
        System.out.println('a' == 97.0); //char and double type
        System.out.println(true == true); //bool type
    }
}

Output:

false
false
true
true

Key difference between equals() and ==