JVM Tutorials - Herong's Tutorial Examples

∟java.lang.System Class - The Operating System

This chapter provides tutorial notes and example codes on java.lang.System class. Topics include accessing standard input, output, and error streams; getting the current time in milliseconds and nanoseconds; accessing environment variables; managing JVM instance properties.

What Is java.lang.System?

Standard Input, Output, and Error Streams

Current Time in Milliseconds and Nanoseconds

Accessing System Environment Variables

Getting and Adding System Properties

Conclusions:

• java.lang.System is a built-in class that represents the operating system.
• in, out and err properties provides standard input, output, and error streams.
• nanoTime() method returns the current time in nanoseconds.
• getenv() method returns all environment variables defined in the operating system.
• getProperties() method returns all properties stored at the JVM instance level.

Table of Contents

 About This Book

 Download and Install Java SE 1.6 Update 2

 java.lang.Runtime Class - The JVM Instance

►java.lang.System Class - The Operating System

 ClassLoader Class - Class Loaders

 Class Class - Class Reflections

 Sun's JVM - Java HotSpot VM

 JRockit JVM 7.0 by BEA Systems

 JRockit JVM 8.0 by BEA Systems

 Memory Management Rules and Tests

 Garbage Collection Tests

 Stack Overflow Tests

 Thread Testing Program and Result

 StringBuffer Testing Program and Result

 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

 References

 PDF Printing Version