I cant under stand why and when we use this method?

Question

Please some oee explain this lesson to me!

Answer 1

examine the following example:

String s1 = new String( "my string" );
String s2 = new String( "my string" );

System.out.println(s1 == s2); // false
System.out.println(s1.equals(s2)); // true

the reason that the == comparison returns false is because it compare the references of the objects rather than checking their values, which is what equals do in this case

another example could be overriding the equals method for your own class:

public class Point{
private int x;
private int y;

public Point( int x, int y) {
this.x = x;
this.y = y;
}

public boolean equals(Object o) {
if (!(o instanceof Point)) {
return false;
}
return (x==((Point)o).x&&y==((Point)o).y);
}
}

in this case, overriding equals would be the best solution to compare 2 Point instances, as they will check each instance x,y value and compare them

while using == will simply compare the reference