Exercise 12.7 implements the bin2Dec method to throw a BinaryFormatException if the string is not a binary string. Define a custom exception called BinaryFormatException. Implement the bin2Dec method to throw a BinaryFormatException if the string is not a binary string.

Write the bin2Dec(String binaryString) method to convert a binary string into a decimal number. Implement the bin2Dec method to throw a NumberFormatException if the string is not a binary string.