Here you can find the source of freeDB(ByteBuffer buffer)
public static void freeDB(ByteBuffer buffer)
//package com.java2s; /**//from w ww . j a v a 2 s . com * 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. */ import java.nio.ByteBuffer; public class Main { /** Forcibly free the direct buffer. */ public static void freeDB(ByteBuffer buffer) { if (buffer instanceof sun.nio.ch.DirectBuffer) { final sun.misc.Cleaner bufferCleaner = ((sun.nio.ch.DirectBuffer) buffer).cleaner(); bufferCleaner.clean(); } } }