What Is HotSpot JVM

This section describes what is HotSpot - A Java Virtual Machine (JVM) originally developed by Sun Microsystems and now supported by Oracle Corporation.

What Is HotSpot? HotSpot, also called Java HotSpot Virtual Machine, or HotSpot JVM, is an implementation of the JVM (Java Virtual Machine) Specification originally developed by Sun Microsystems and now supported by Oracle Corporation.

HotSpot has key feature called adaptive compiler that application code will be analyzed as it runs to detect performance bottlenecks, or "hot spots". HotSpot will then compile those hot spots for a boost in performance.

There are two implementations of the HotSport:

The main differences of the two implementations are:

Both implementations of HotSpot are distributed inside the JDK (Java Development Kit) package and the JRE (Java Runtime Environment) package.

By the way, HotSpot source code is available at http://openjdk.java.net/groups/hotspot/.

Table of Contents

 About This Book

 JVM (Java Virtual Machine) Specification

Java HotSpot VM - JVM by Oracle/Sun

What Is HotSpot JVM

 Download and Install JDK on macOS

 Download and Install JDK on Windows

 Running Java HotSpot Client VM

 Running Java HotSpot Server VM

 HotSpot Memory Usages on Windows Systems

 java.lang.Runtime Class - The JVM Instance

 java.lang.System Class - The Operating System

 ClassLoader Class - Class Loaders

 Class Class - Class Reflections

 JVM Runtime Data Areas

 JVM Stack, Frame and Stack Overflow

 Thread Testing Program and Result

 CPU Impact of Multi-Thread Applications

 I/O Impact of Multi-Thread Applications

 CDS (Class Data Sharing)

 Micro Benchmark Runner and JVM Options

 Micro Benchmark Tests on "int" Operations

 Micro Benchmark Tests on "long" Operations

 Micro Benchmark Tests in JIT Compilation Mode

 Micro Benchmark Tests on "float" and "double" Operations

 OpenJ9 by Eclipse Foundation

 JRockit JVM 28.2.7 by Oracle Corporation

 Archived Tutorials

 References

 Full Version in PDF/EPUB