Here you can find the source of arrayToString(Object... keys)
private static String arrayToString(Object... keys)
//package com.java2s; public class Main { private static String arrayToString(Object... keys) { StringBuffer buffer = new StringBuffer(); for (int i = 0; i < keys.length; i++) { buffer.append(keys[i]);// w w w.j a va 2 s .c om if (i != keys.length - 1) { buffer.append(","); } } return buffer.toString(); } }