Java Enum compareTo() Method

The compareTo() method of Enum class compares this enum object with the defined object for order.

Enum constants can only be compared to other enum constants of the same type.

Syntax

Parameters

o - It is the enum object that is compared

Return Value

The compareTo() method returns:

negativeinteger, if this enum is less than the defined object.
zero, if this enum is equal to the defined object.
positive integer, if this enum is greater than the defined object.

Example 1

public class Enum_compareToMethodExample1 {

enum Grade{
A1,A2;
    }
public static void main(String[] args) {

        Grade first, second, third;

first = Grade.A1;

second = Grade.A2;

int val = first.compareTo(second);

if(val>0){

System.out.println("A1 is greater than A2.");
        }

else if(val<0){
System.out.println("A2 is greater than A1.");
        }

else{

System.out.println("A1 and A2 both are equal .");

        }
    }
}

Output:

A2 is greater than A1.

Example 2

public class Enum_compareToMethodExample2 {
//we can declare an enum inside a class or outside a class but not inside an method.
enum Season {
summer, winter, spring;
    }
public static void main(String[] args) {
    Season sesn1, sesn2, sesn3;
        sesn1 = Season.spring;
        sesn2 = Season.summer;
        sesn3 = Season.winter;
int val1 = sesn1.compareTo(sesn2);
int val2 =sesn1.compareTo(sesn3);
int val3 =sesn3.compareTo(sesn2);
System.out.println("Val1= "+val1+"   Val2= "+val2+"   Val3= "+val3);
if(val1>0&&val2>0){
System.out.println("Spring is my Fav season amongst all seasons.");
        }
else if(val1<0&&val3<0){
System.out.println("Summer is my fav season amongst all seasons.");
        }
else{
System.out.println("Winter is my favfav season amongst all seasons.");
        }
      }
    }

Output:

Val1= 2   Val2= 1   Val3= 1
Spring is my Fav season amongst all seasons.

Example 3

public class Enum_compareToMethodExample3{
enumColour{
red,Red;
    }

public static void main(String[] args) {
        Colour red, Red;
        red = Colour.red;
        Red = Colour.Red;
//Upper case has higher value than lower case.
int val = red.compareTo(Red);

if( val>0){
System.out.println("red is greater than Red.");
        }
else if(val<0){
System.out.println("Red is greater than red.");
        }
else{
System.out.println("red and Red both are equal .");
        }
    }
    }

Output: