Java lang Integer.toHexString() Method with Examples

The Java.lang.Integer.toHexString() is a built-in function in Java which returns a string representation of the integer argument as an unsigned integer in base 16. The function accepts a single parameter as an argument in Integer data-type.

Syntax :

public static String toHexString(int num)

Parameter : The function accepts a single mandatory parameter
num - This parameter specifies the number which is to be converted
to a Hexadecimal string. The data-type is int. 

Return Value : The function returns a string representation of the int argument as an unsigned integer in base 16.

Examples:

Input : 11
Output : b

Input : 12
Output : c

Program 1: The program below demonstrates the working of function.

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

class Gfg1 {

    // driver code
    public static void main(String args[])
    {

        int l = 234;

        // returns the string representation of the unsigned int value
        // represented by the argument in binary (base 2)
        System.out.println("Hex string is " + Integer.toHexString(l));

        l = 11;
        System.out.println("Hex string is " + Integer.toHexString(l));
    }
}

Output:

Hex string is ea
Hex string is b

Program 2: The program below demonstrates the working function when a negative number is passed.

// Java program to demonstrate
// of java.lang.Integer.toHexString() method
// negative number

import java.lang.Math;

class Gfg1 {

    // driver code
    public static void main(String args[])
    {
        // when negative number is passed
        System.out.println("Hex is " + Integer.toHexString(-10));
    }
}

Output:

Hex is fffffff6

Errors and Exception: Whenever a decimal number or a string is passed as an argument, it returns an error message which says “incompatible types”.

Program 3: The program below demonstrates the working function when a string number is passed.

// Java program to demonstrate
// of java.lang.Integer.toHexString() method
// string number

import java.lang.Math;

class Gfg1 {

    // driver code
    public static void main(String args[])
    {
        // when negative number is passed
        System.out.println("Hex is " + Integer.toHexString("12"));
    }
}

Output:

prog.java:13: error: incompatible types: String cannot be converted to int
    System.out.println("Hex is " + Integer.toHexString("12")); 

Program 4: The program below demonstrates the working function when a decimal is passed.

// Java program to demonstrate
// of java.lang.Integer.toHexString() method
// decimal

import java.lang.Math;

class Gfg1 {

    // driver code
    public static void main(String args[])
    {
        // when decimal number is passed
        System.out.println("Hex is " + Integer.toHexString(12.34));
    }
}

Output:

prog.java:13: error: incompatible types: possible lossy conversion from double to int
    System.out.println("Hex is " + Integer.toHexString(12.34));