External Interfaces/API

Calling Java from MATLAB

This chapter describes how to use the MATLAB interface to Java classes and objects. This MATLAB capability enables you to conveniently bring Java classes into the MATLAB environment, to construct objects from those classes, to call methods on the Java objects, and to save Java objects for later reloading -- all accomplished with MATLAB functions and commands.

The following list summarizes the contents of this chapter:

• Using Java from MATLAB: An Overview
• Bringing Java Classes into MATLAB
• Creating and Using Java Objects
• Invoking Methods on Java Objects
• Working with Java Arrays
• Passing Data to a Java Method
• Handling Data Returned from a Java Method
• Introduction to Programming Examples

Using Java from MATLAB: An Overview

Java Interface Is Integral to MATLAB

Every installation of MATLAB includes a Java Virtual Machine (JVM), so that you can use the Java interpreter via MATLAB commands, and you can create and run programs that create and access Java objects. For information on MATLAB installation, see the MATLAB installation documentation for your platform.

Benefits of the MATLAB Java Interface

The MATLAB Java interface enables you to:

• Access Java API (application programming interface) class packages that support essential activities such as I/O and networking. For example, the URL class provides convenient access to resources on the internet
• Access third-party Java classes
• Easily construct Java objects in MATLAB
• Call Java object methods, using either Java or MATLAB syntax
• Pass data seamlessly between MATLAB variables and Java objects

Who Should Use the MATLAB Java Interface

The MATLAB Java interface is intended for all MATLAB users who want to take advantage of the special capabilities of the Java programming language. For example:

• You need to access, from MATLAB, the capabilities of available Java classes.
• You are familiar with object-oriented programming in Java or in another language, such as C++.
• You are familiar with MATLAB object-oriented classes, or with MATLAB MEX-files.

To Learn More About Java Programming

For a complete description of the Java language and for guidance in object-oriented software design and programming, you'll need to consult outside resources. For example, these recently published books may be helpful:

• Java in a Nutshell (Second Edition), by David Flanagan
• Teach Yourself Java in 21 Days, by Lemay and Perkins

Another place to find information is the JavaSoft Web site.

http://www.javasoft.com

For other suggestions on object-oriented programming resources, see:

• Object Oriented Software Construction, by Bertrand Meyer
• Object Oriented Analysis and Design with Applications, by Grady Booch

Platform Support for the Java Virtual Machine

To find out which version of the Java Virtual Machine (JVM) is being used by MATLAB on your platform, type the following at the MATLAB prompt:

version -java

Compiling and Linking on Windows

Bringing Java Classes into MATLAB