Using the JRockit Memory Leak Detector

Introduction

This product is provided "as-is," without any expressed or implied warranties or support by BEA Systems, Inc. This product, which may or may not become an officially supported product from BEA Systems, may contain errors and/or inaccuracies. Use of this product is left solely upon the discretion of the user without any endorsement from BEA Systems. The Memory Leak Detector functionality may or may not be available in future BEA JRockit versions. Questions and problems may be reported via online BEA JRockit newsgroups at http://newsgroups.bea.com.

The BEA JRockit Memory Leak Detector detects memory leaks within Java applications that run on BEA JRockit. A memory leak means application code is holding on to memory that is not used by the application any more. The BEA JRockit Memory Leak Detector is a real-time profiling tool that gives information about what type of objects are allocated, how many, of what size, and how they relate to each other. Unlike other similar tools, there is no need to create full heap dumps that you need to analyze at a later stage. The data presented is fetched directly from the running JVM, which can continue to run with a relatively small overhead. When the analysis is done, the tool can be disconnected and the JVM will run at full speed again. This makes the tool viable for use in a production environment.

The purpose of this tool is to display memory leaking object types (that is, classes) and provide help to track the source of the problem. Another purpose of this tool is to help increase the understanding and knowledge to avoid similar programming errors in future projects.

Note: To access the full version of the BEA JRockit Memory Leak Detector, JRockit J2SE 5.0 sp1 or higher is required.

The following subjects are covered in this section:

What is New in the BEA JRockit Memory Leak Detector?

The biggest change from the previous version of the Memory Leak Detector for BEA JRockit 1.4.2_05 is that it is now a stand-alone tool and you do not need to access it through the BEA JRockit Management Console.
Major improvements on usability and look and feel have also been done.

The BEA JRockit Memory Leak Detector Overhead

The extra cost of running the BEA JRockit Memory Leak Detector against a running BEA JRockit is very small and is noticeable only in that garbage collections take a little bit more time. The overhead of enabling allocation stack traces can be more significant and should therefore be used with care. This provides for a low cost monitoring and profiling of your application.

About this User Guide

In this document you will be guided through how you can spot a memory leak in your Java application. You will also get hints on how to repair a memory leak. This user guide assumes that you know what a JVM is and that you are familiar with Java application development.

Finding Additional Information

You can find additional information about BEA JRockit throughout the BEA JRockit documentation set. For a complete list of available documents, please refer to the BEA JRockit Online Documentation.