myeclipse序列号注册生成Java代码

import java.io.*;   
 public class MyEclipseGen {   
    private static final String LL = "Decompiling this copyrighted software is a violation of both your license agreement and the Digital Millenium Copyright Act of 1998 (http://www.loc.gov/copyright/legislation/dmca.pdf). Under section 1204 of the DMCA, penalties range up to a $500,000 fine or up to five years imprisonment for a first offense. Think about it; pay for a license, avoid prosecution, and feel better about yourself.";//定义一个String字符串   
    public String getSerial(String userId, String licenseNum) {   
        java.util.Calendar cal = java.util.Calendar.getInstance();   
        cal.add(1, 3);   
        cal.add(6, -1);   
        java.text.NumberFormat nf = new java.text.DecimalFormat("000");   
        licenseNum = nf.format(Integer.valueOf(licenseNum));   
        String verTime = new StringBuilder("-").append(new java.text.   
                SimpleDateFormat("yyMMdd").format(cal.getTime())).append("0").   
                         toString();   
        String type = "YE3MP-";   
        String need = new StringBuilder(userId.substring(0, 1)).append(type).   
                      append("300").append(licenseNum).append(verTime).toString();   
        String dx = new StringBuilder(need).append(LL).append(userId).toString();   
        int suf = this.decode(dx);   
        String code = new StringBuilder(need).append(String.valueOf(suf)).   
                      toString();   
        return this.change(code);   
    }   
  
    private int decode(String s) {   
        int i;   
        char[] ac;   
        int j;   
        int k;   
        i = 0;   
        ac = s.toCharArray();   
        j = 0;