In this source code example, we will write a Java program that converts any HexaDecimal number to a Binary number.

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Java Convert Hexadecimal to Binary

This class converts HexaDecimal number to a Binary number:

package net.sourcecodeexamples.java.Conversions;

//Hex [0-9],[A-F] -> Binary [0,1]

/**
 * This class converts Decimal numbers to Octal Numbers
 * @author sourcecodeexamples.net
 *
 */
public class HexaDecimalToBinary {

    private final int LONG_BITS = 8;

    public void convert(String numHex) {
        // String a HexaDecimal:
        int conHex = Integer.parseInt(numHex, 16);
        // Hex a Binary:
        String binary = Integer.toBinaryString(conHex);
        // Output:
        System.out.println(numHex + " = " + completeDigits(binary));
    }

    public String completeDigits(String binNum) {
        for (int i = binNum.length(); i < LONG_BITS; i++) {
            binNum = "0" + binNum;
        }
        return binNum;
    }

    public static void main(String[] args) {

        //Testing Numbers:
        String[] hexNums = {
            "1",
            "A1",
            "ef",
            "BA",
            "AA",
            "BB",
            "19",
            "01",
            "02",
            "03",
            "04"
        };
        HexaDecimalToBinary objConvert = new HexaDecimalToBinary();

        for (String num: hexNums) {
            objConvert.convert(num);
        }
    }
}

Output

1 = 00000001
A1 = 10100001
ef = 11101111
BA = 10111010
AA = 10101010
BB = 10111011
19 = 00011001
01 = 00000001
02 = 00000010
03 = 00000011
04 = 00000100

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