For my computer science labe are required to convert from hexidecimal (base 16) to base 2.

Can someone help me by telling me how i should begin? I sure it starts with some kind of loop, but from then on i'm stumped.

Code:

// Lab16st.java
// The Number System Converter
// Student Version
import java.util.Scanner;
public class Lab16st
{
public static void main (String args[])
{
System.out.println("Lab 16 - Number Conversion Program\n\n");
// The next 2 lines are used in all versions.
System.out.println("ABCD1234 Base-16 converts to " + BaseConverter.fromHexToBin("ABCD1234") + " in Base-2.\n");
System.out.println("E12B47F5 Base-16 converts to " + BaseConverter.fromHexToBin("E12B47F5") + " in Base-2.\n");
// The next 2 lines are used in the 90-point versions and above.
// System.out.println("1011111011101111 Base-2 converts to " + BaseConverter.fromBinToDec("1011111011101111") + " in Base-10.\n");
// System.out.println("11100100100110110 Base-2 converts to " + BaseConverter.fromBinToDec("11100100100110110") + " in Base-10.\n");
// The next line is used in the 95-point versions and above.
// System.out.println("1011111011101111 Base-2 converts to " + BaseConverter.fromBinToHex("1011111011101111") + " in Base-16.\n");
// The next line is used in the 100-point versions and above.
// System.out.println("11100100100110110 Base-2 converts to " + BaseConverter.fromBinToHex("11100100100110110") + " in Base-16.\n");
// The next 3 lines are used in the 105 and 110-point versions.
// System.out.println("1000 Base-10 converts to " + BaseConverter.fromDecToAny(1000,5) + " in Base-5.\n");
// System.out.println("1000 Base-10 converts to " + BaseConverter.fromDecToAny(1000,8) + " in Base-8.\n");
// System.out.println("200 Base-10 converts to " + BaseConverter.fromDecToAny(200,2) + " in Base-2.\n");
// This last line is only used in the 110 point version.
// System.out.println("48879 Base-10 converts to " + BaseConverter.fromDecToAny(48879,16) + " in Base-16.\n");
}
}
class BaseConverter
{
public static String fromHexToBin(String hexNum)
{
String binNum = "";
return binNum;
}