Comparing enum members: == or equals () in Java ?

Question

Aryan Kumar · Answer

The == operator and equals() method can both be used to compare enum members. However, there are some key differences between the two.

The == operator checks reference equality. This means that it checks if the two objects are the same reference in memory. For enum members, this will always be true, since there is only one instance of each enum constant.
The equals() method checks value equality. This means that it checks if the two objects have the same values. For enum members, this will also be true, since the values of all enum constants are unique.

In most cases, it is safe to use the == operator to compare enum members. However, there are some cases where it can be misleading. For example, if you have two enum variables that are declared as null, the == operator will return true, even though the enum constants themselves are not equal.

For this reason, it is generally recommended to use the equals() method to compare enum members. The equals() method is more reliable and will not return unexpected results.

Here is an example of how to compare enum members using the == operator and the equals() method:

enum Color {
  RED, GREEN, BLUE
}

public class Main {

  public static void main(String[] args) {
    Color c1 = Color.RED;
    Color c2 = Color.RED;

    // The == operator will return true, even though c1 and c2 are two different variables.
    System.out.println(c1 == c2); // true

    // The equals() method will return true, since the values of c1 and c2 are the same.
    System.out.println(c1.equals(c2)); // true

    // The following code will return false, since c3 is null.
    Color c3 = null;
    System.out.println(c1 == c3); // false

    // The following code will also return false, since the values of c1 and c3 are not the same.
    System.out.println(c1.equals(c3)); // false
  }
}

As you can see, the == operator is not always reliable when comparing enum members. The equals() method is a more reliable way to compare enum members.

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Comparing enum members: == or equals () in Java ?

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