Here you can find the source of getMemoryUsage()
public static long getMemoryUsage()
//package com.java2s; /* //from w ww .j a va2s.c o m * Copyright 2008-2010 the original author or authors * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ public class Main { /** * @return JVM freeMemory in Mo */ public static long getMemoryUsage() { return getTotalMemory() - getFreeMemory(); } /** * @return JVM totalMemory in Mo */ public static long getTotalMemory() { return (Runtime.getRuntime().totalMemory() / 1024); } /** * @return JVM freeMemory in Mo */ public static long getFreeMemory() { return (Runtime.getRuntime().freeMemory() / 1024); } }