Here you can find the source of totalMemory()
Runtime.getRuntime().totalMemory()
public static long totalMemory()
//package com.java2s; /*/*from www . j av a2 s .c om*/ * (c) 2005 David B. Bracewell * * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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 { /** * Wrapper around <code>Runtime.getRuntime().totalMemory()</code> * * @return the total amount of memory in the Java virtual machine. */ public static long totalMemory() { return Runtime.getRuntime().totalMemory(); } }