Convert from Binary, Octal or Hex to Decimal number in java

Use Integer.parseInt(String input, int radix) to convert from any type of number to an Integer.

String binaryNumber = "10101";

int decimal1 = Integer.parseInt(binaryNumber, 2);

System.out.println(binaryNumber + " in Base 10 : " + decimal1);

String octalNumber = "456";

int decimal2 = Integer.parseInt(octalNumber, 8);

System.out.println(octalNumber + " in Base 10 : " + decimal2);

String hexNumber = "ABCD";

int decimal3 = Integer.parseInt(hexNumber, 16);

System.out.println(hexNumber + " in Base 10 : " + decimal3);

Output:

10101 in Base 10 : 21

456 in Base 10 : 302

ABCD in Base 10 : 43981