Here you can find the source of getProperty(Properties props, String prefix, String key)
public static String getProperty(Properties props, String prefix, String key)
//package com.java2s; //License from project: Open Source License import java.util.*; public class Main { public static String getProperty(Properties props, String prefix, String key) { return props.getProperty((prefix != null) ? prefix + "." + key : key); }//from w w w.j av a2s . c om public static String getProperty(Properties props, String prefix, String key, String defaultVal) { return props.getProperty((prefix != null) ? prefix + "." + key : key, defaultVal); } }