What Is Runtime?

This section describes what is Runtime - A Java built-in class, java.lang.Runtime, that presents running instances of a Java Virtual Machine (JVM).

What Is Runtime? java.lang.RunTime is a built-in class that presents running instances of a Java Virtual Machine (JVM). In other word, every Java running application has a single instance of class Runtime. To access the instance of RunTime of the current JVM, you can use the static class method, getRuntime().

Runtime class allows the application to interface with the JVM instance through these methods:

Tutorial example programs are provided in next sections to test those methods.

Last update: 2014.

Table of Contents

 About This Book

 JVM (Java Virtual Machine) Specification

 Java HotSpot VM - JVM by Oracle/Sun

java.lang.Runtime Class - The JVM Instance

What Is Runtime?

 Printing Runtime Basic Information

 Running the Garbage Collector Explicitly

 Shutting Down or Terminating the JVM Instance

 Executing System Commands

 Loading Native Libraries

 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

 JRockit JVM 28.2.7 by Oracle Corporation

 Outdated Tutorials

 References

 Full Version in PDF/EPUB