Eckhart generator with real id, Java

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//'main' method must be in a class 'Rextester'.
//Compiler version 1.8.0_111

import java.util.*;
import java.lang.*;

class Rextester
{  
    public static String ID = "";
    public static ArrayList<Integer> mois = new ArrayList<Integer>();
    
    public static void main(String args[])
    {
        String[][] name = new String[][]{
            {"ck", "kk", "gg", "k", "g", "gk"},
            {"e", ""},
            {"h", ""},
            {"r", ""},
            {"t", "th", "dd", "dt", "d"}
        };
        Integer rID = 1;
        String p1 = Random(name[0]);
        String p2 = Random(name[1]);
        String p3 = Random(name[2]);
        String p4 = Random(name[3]);
        String p5 = Random(name[4]);
        
        System.out.println("E" + p1 + p2 + p3 + "a" + p4 + p5);
        System.out.println("ID: " + ID);
        
        Integer rID2 = 1;
        for(int i = 0; i < name.length; i++){
            rID2 = CalcID(rID2, name[i].length, mois.get(i));
        }
        System.out.println("Real ID: " + rID2);
    }
    
    public static String Random(String[] input){
        int index = (int)(Math.random() * input.length);
        ID += "" + index;
        mois.add(index+1);
        return input[index];
    }
    
    public static Integer CalcID(Integer prevID, Integer poss, Integer fall){
        return(prevID * poss + (-(poss) + fall));
    }
}

[ + ] Show input
Compilation time: 1.25 sec, absolute running time: 0.25 sec, cpu time: 0.25 sec, memory peak: 18 Mb, absolute service time: 1,5 sec