java == vs equals
In general both equals() and == operator in Java are used to compare
objects to check equality but here are some of the differences between the two:
1) .equals() and == is that one is a method and other is operator.
2) We can use == operator for reference comparison (address comparison)
and .equals() method for content comparison.
-> == checks if both objects point to the same memory location
-> .equals() evaluates to the comparison of values in the objects.
3) If a class does not override the equals method, then by default it
uses equals(Object o) method of the closest parent class
that has overridden this method.
// Java program to understand
// the concept of == operator
public class Test {
public static void main(String[] args)
{
String s1 = new String("HELLO");
String s2 = new String("HELLO");
System.out.println(s1 == s2);
System.out.println(s1.equals(s2));
}
}
Output:
false
true
Explanation: Here we are creating two (String) objects namely s1 and s2.
Both s1 and s2 refers to different objects.
-> When we use == operator for s1 and s2 comparison then the result is false
as both have different addresses in memory.
-> Using equals, the result is true because its only comparing the
values given in s1 and s2.