How can I make my test file work?

I have 3 class files: Bin2Dec implements to throw an exception, BinaryFormatException is the exception file, and bin2DecTest is the test file to test the correct operation of both the BinaryFormatException and bin2Dec. I don't know why but I can't get the test file to run. Someone please help me!!

TEST FILE:

    //Prepare scanner from utility for input.
    import java.util.Scanner;
    public class bin2DecTest {
        public static void main (String[] args){
            //Convert the input string to their decimal equivalent.
                //Open scanner for input.
                    Scanner input = new Scanner(System.in);
                    //Declare variable s.
                    String s;

            //Prompt user to enter binary string of 0s and 1s.
            System.out.print("Enter a binary string of 0s and 1s: ");
            //Save input to s variable.
            s = input.nextLine();
                //With the input, use try-catch blocks.
                //Print statement if input is valid with the conversion.
                try {
                 System.out.println("The decimal value of the binary number "+ "'" + s + "'" +" is "+conversion(s));
                 //Catch the exception if input is invalid.
                  } catch (BinaryFormatException e) {
                      //If invalid, print the error message from BinaryFormatException.
                    System.out.println(e.getMessage());
                  }
                }
    }

Bin2Dec FILE:

    //Prepare scanner from utility for input.
    import java.util.Scanner;
    public class Bin2Dec {
                  //Declare exception.

          public static int conversion(String parameter) throws BinaryFormatException {
            int digit = 0;

          for (int i = 0; i < parameter.length(); i++) {
              char wrong_number = parameter.charAt(i);


              if (wrong_number != '1' && wrong_number != '0') { 
                throw new BinaryFormatException("");
              }

              //Make an else statement and throw an exception.

              else 
                digit = digit * 2 + parameter.charAt(i) - '0';
            }
            return digit;
          } 
        }

BinaryFormatException FILE:

    //Define a custom exception called BinaryFormatException.
    public class BinaryFormatException extends Exception {
        //Declare message.
          private String message;
          public BinaryFormatException(String msg) {
            this.message = msg;
          }
          //Return this message for invalid input to Bin2Dec class.
          public String getMessage() {
             return "Error: This is not a binary number";
          }
        }