Java tutorial
/* * Copyright 2012-2019 CodeLibs Project and the Others. * * 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. */ package org.codelibs.fess.util; import org.apache.commons.io.FileUtils; import org.codelibs.core.lang.StringUtil; public final class MemoryUtil { private MemoryUtil() { } public static String getMemoryUsageLog() { final Runtime runtime = Runtime.getRuntime(); final long freeBytes = runtime.freeMemory(); final long maxBytes = runtime.maxMemory(); final long totalBytes = runtime.totalMemory(); final long usedBytes = totalBytes - freeBytes; return "Mem:{used " + byteCountToDisplaySize(usedBytes) + ", heap " + byteCountToDisplaySize(totalBytes) + ", max " + byteCountToDisplaySize(maxBytes) + "}"; } public static String byteCountToDisplaySize(final long size) { return FileUtils.byteCountToDisplaySize(size).replace(" ", StringUtil.EMPTY); } public static long getUsedMemory() { final Runtime runtime = Runtime.getRuntime(); final long freeBytes = runtime.freeMemory(); final long totalBytes = runtime.totalMemory(); return totalBytes - freeBytes; } }