MyEclipseGen

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.";     
    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;     
        k = ac.length;     
        while (j < k) {     
            i = (31 * i) + ac[j];     
            j++;     
        }     
        return Math.abs(i);     
    }     
    
    private String change(String s) {     
        byte[] abyte0;     
        char[] ac;     
        int i;     
        int k;     
        int j;     
        abyte0 = s.getBytes();     
        ac = new char[s.length()];     
        i = 0;     
        k = abyte0.length;     
        while (i < k) {     
            j = abyte0[i];     
            if ((j >= 48) && (j <= 57)) {     
                j = (((j - 48) + 5) % 10) + 48;     
            } else if ((j >= 65) && (j <= 90)) {     
                j = (((j - 65) + 13) % 26) + 65;     
            } else if ((j >= 97) && (j <= 122)) {     
                j = (((j - 97) + 13) % 26) + 97;     
            }     
            ac[i] = (char) j;     
            i++;     
        }     
        return String.valueOf(ac);     
    }     
    
    public MyEclipseGen() {     
        super();     
    }     
    
    public static void main(String[] args) {     
        try {     
            System.out.println("please input register name:");     
            BufferedReader reader = new BufferedReader(new InputStreamReader(     
                    System.in));     
            String userId = null;     
            userId = reader.readLine();     
            MyEclipseGen myeclipsegen = new MyEclipseGen();     
            String res = myeclipsegen.getSerial(userId, "20");     
            System.out.println("Serial:" + res);     
            reader.readLine();     
        } catch (IOException ex) {     
        }     
    }     
}