Java Integer compareTo() method

The compareTo() method of Integer class of java.lang package compares two Integer objects numerically and returns the value 0 if this Integer is equal to the argument Integer; a value less than 0 if this Integer is numerically less than the argument Integer; and a value greater than 0 if this Integer is numerically greater than the argument Integer (signed comparison). 

Syntax :

public int compareTo(Integer anotherInt)
Parameter :
anotherInt- : the Integer to be compared.
Return :
- This method returns the value 0 if this Integer is 
equal to the argument Integer; 
- a value less than 0 if this Integer is 
numerically less than the argument Integer; 
- and a value greater than 0 if this Integer is
numerically greater than the argument Integer
(signed comparison).

Example 01 : To show working of java.lang.Integer.compareTo() method. 

java

// Java program to demonstrate working
// of java.lang.Integer.compareTo() method
import java.lang.Integer;

class Gfg {

    // driver code
    public static void main(String args[])
    {
        Integer a = new Integer(10);
        Integer b = new Integer(20);

        // as 10 less than 20, Output will be a value less than zero
        System.out.println(a.compareTo(b));

        Integer x = new Integer(30);
        Integer y = new Integer(30);

        // as 30 equals 30, Output will be zero
        System.out.println(x.compareTo(y));

        Integer w = new Integer(15);
        Integer z = new Integer(8);

        // as 15 is greater than 8, Output will be a value greater than zero
        System.out.println(w.compareTo(z));
    }
}

Output:

-1
0
1

Example 02 :The working of compareTo() method in Java to compare two integer values.

Java

import java.io.*;

class GFG {
    public static void main(String[] args)
    {
        Integer num1 = 10;
        Integer num2 = 5;
        Integer num3 = 10;
        int result1 = num1.compareTo(num2);
        int result2 = num1.compareTo(num3);
        int result3 = num2.compareTo(num3);
        System.out.println("Comparing num1 and num2: "
                           + result1);
        System.out.println("Comparing num1 and num3: "
                           + result2);
        System.out.println("Comparing num2 and num3: "
                           + result3);
    }
}

Output :

Comparing num1 and num2: 1
Comparing num1 and num3: 0
Comparing num2 and num3: -1