Book Image

Java Memory Management

By : Maaike van Putten, Dr. Seán Kennedy
Book Image

Java Memory Management

By: Maaike van Putten, Dr. Seán Kennedy

Overview of this book

Understanding how Java organizes memory is important for every Java professional, but this particular topic is a common knowledge gap for many software professionals. Having in-depth knowledge of memory functioning and management is incredibly useful in writing and analyzing code, as well as debugging memory problems. In fact, it can be just the knowledge you need to level up your skills and career. In this book, you’ll start by working through the basics of Java memory. After that, you’ll dive into the different segments individually. You’ll explore the stack, the heap, and the Metaspace. Next, you’ll be ready to delve into JVM standard garbage collectors. The book will also show you how to tune, monitor and profile JVM memory management. Later chapters will guide you on how to avoid and spot memory leaks. By the end of this book, you’ll have understood how Java manages memory and how to customize it for the benefit of your applications.
Table of Contents (10 chapters)

Zooming in on the Metaspace

In Chapter 4, we examined garbage collection in detail. We discovered that objects without a reference are eligible for garbage collection. In effect, the garbage collector marks the objects that have a connection back to the stack, annotating them as live objects. The sweep phase of the garbage collector then reclaims the memory of the objects that are not marked (the dead objects).

We also examined the various garbage collection implementations. Based on your specific criteria, an evaluation of each implementation is required.

This chapter focuses on an area known as the Metaspace. We will examine the Metaspace under the following headings:

  • JVM usage of the Metaspace
  • Class loading
  • Releasing Metaspace memory

Let us start with the JVM usage of the Metaspace.