usejava

Determine if Java feature is available

Syntax

tf = usejava(feature)

Description

tf = usejava(feature) returns logical 1 (true) if the specified feature is supported. Otherwise, it returns logical 0 (false). If the Java^® feature is unavailable, then you can use this function for error handling.

Examples

Display Error Message

Use the following code snippet to test that the AWT GUI components are available before attempting to display a Java Frame. If the AWT is not available on your system, MATLAB^® displays the message Unable to open a Java Frame.

if usejava('awt')
   myFrame = java.awt.Frame;
else
   disp('Unable to open a Java Frame')
end

Call error Function

Use the following code snippet to terminate a script if MATLAB does not have access to JVM^® software.

The variable, filename, is a function that contains Java code.

if ~usejava('jvm')
   error([filename ' requires Java to run.'])
end

Input Arguments

feature — Java feature

'awt' | 'desktop' | 'jvm' | 'swing'

Java feature, specified as one of these values.

'awt'	UI components in the Java Abstract Window Toolkit (AWT) are available.
'desktop'	MATLAB interactive desktop is running. For more information, see desktop option will not be supported.
'jvm'	Java Virtual Machine software (JVM) is available.
'swing'	Swing components (Java lightweight UI components in the Java Foundation Classes) are available.

Extended Capabilities

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.

Version History

Introduced before R2006a

R2025a: desktop option will not be supported

The desktop option for the feature argument will be removed in a future release.