What's the difference between “.equals” and “==”? [duplicate]

Answer 1

Lets say that "==" operator returns true if both both operands belong to same object but when it will return true as we can't assign a single object multiple values

public static void main(String [] args){
    String s1 = "Hello";
    String s1 = "Hello";  // This is not possible to assign multiple values to single object
    if(s1 == s1){
      // Now this retruns true
   }
}

Now when this happens practically speaking, If its not happen then why this is == compares functionality....