Simple example to demonstrate issue

MyParser.java

package se.sjv.jorden.datachange;

import com.google.common.base.Preconditions;

public class MyParser {

    public static void main(final String[] args) {
        final MyParser myParser = new MyParser();
        Preconditions.checkArgument(args.length == 1, "Incorrect number of arguments.");

        // do something before parsing

        myParser.parse(args[0]);

        // do something after parsing
    }

    private void parse(final String input) {
        final String[] tokens = input.split(";");
        Preconditions.checkArgument(tokens.length == 3);

        try {
            System.out.println("First parameter: " + parseFirstParam(tokens[0]));
            System.out.println("Second parameter: " + parseSecondParam(tokens[1]));
            System.out.println("Third parameter: " + parseThirdParam(tokens[2]));
        } catch (final IllegalArgumentException e) {
            System.err.println("Error while parsing parameters: " + e.getMessage());
        }
    }

    private String parseFirstParam(final String string) {
        return string.trim().toLowerCase();
    }

    private String parseSecondParam(final String string) /* throws IllegalArgumentException */ {
        final int parsedInt = Integer.parseInt(string); // this may throw NumberFormatException,
                                                        // which is a subclass of IllegalArgumentException
        return String.format("%d st", parsedInt * 100);
    }

    private String parseThirdParam(final String string) {
        return string.trim().toUpperCase();
    }

}