Loading Native Libraries

This section provides a tutorial example on how to load native libraries (DLL files on Windows systems) with loadLibrary() and load() methods.

The JVM instance also allows you to load native libraries into the system to support native methods by using loadLibrary() and load() methods:

Here is tutorial example program testing loadLibrary() and load() methods:

/**
 * RuntimeLoadLibrary.java
 * Copyright (c) 2013, HerongYang.com, All Rights Reserved.
 */
class RuntimeLoadLibrary {
   public static void main(String[] a) {
      java.io.PrintStream out = System.out;
      Runtime rt = Runtime.getRuntime();
     
      try {
         out.println("Loading a native library...");
         // rt.loadLibrary("msvcr71"); // c:/local/jdk/bin/msvcr71.dll
         rt.loadLibrary("java"); // c:/local/jdk/bin/java.dll

         out.println("Loading a native code...");
         rt.load("c:/local/jdk/bin/java.exe");
      } catch (Exception e) {
         e.printStackTrace();
      }
   }
}

When executed on my Windows 7 system with JDK 1.7.0, I got this result, assuming that java.dll and java.exe are exists in folder: \local\jdk\bin:

C:\herong\jvm>java RuntimeLoadLibrary
Loading a native library...
Loading a native code...

The test result tells me that:

Comparing to the same test with JDK 1.6.0 in 2010, the behavior of rt.load() is not changed.

I don't have any example programs for calling native methods provided in native libraries yet.

Last update: 2014.

Table of Contents

 About This Book

 Downloading and Installing JDK 1.8.0 on Windows

 Downloading and Installing JDK 1.7.0 on Windows

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

 Sun's JVM - Java HotSpot VM

 JRockit JVM 28.2.7 by Oracle Corporation

 JVM Runtime Data Areas

 Memory Management and Garbage Collectors

 Garbage Collection Tests

 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

 Outdated Tutorials

 References

 PDF Printing Version