Here you can find the source of getMemoryUsage()
public static double getMemoryUsage()
//package com.java2s; /******************************************************************************* * Copyright [2014] [Joarder Kamal]//from w ww .j ava 2 s . co m * * 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 { static public final long MEGABYTE_SIZE = 1024L * 1024L; public static double getMemoryUsage() { long usedMemory = Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory(); return (double) usedMemory / (double) MEGABYTE_SIZE; } }