Here you can find the source of usedMemoryMB()
public static double usedMemoryMB()
//package com.java2s; /*/*from www. j a va 2s. c om*/ * Copyright [2013-2014] eBay Software Foundation * * 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 { /** * Get used memory in megabytes * * @return free memory in megabytes */ public static double usedMemoryMB() { return megaBytes(Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory()); } /** * Get megabytes */ private static double megaBytes(long bytes) { return bytes / 1024.0 / 1024.0; } }