usejava (External Interfaces Reference)

Determine if Java feature is supported in MATLAB

Syntax

```
usejava(feature)
```

Description

usejava(feature) returns 1 if the specified feature is supported and 0 otherwise. Possible feature arguments are shown in the following table.

Feature
Description

'awt'
Abstract Window Toolkit components¹ are available

'desktop'
The MATLAB interactive desktop is running

'jvm'
The Java Virtual Machine is running

'swing'
Swing components² are available

Feature	Description
`'awt'`	Abstract Window Toolkit components¹ are available
`'desktop'`	The MATLAB interactive desktop is running
`'jvm'`	The Java Virtual Machine is running
`'swing'`	Swing components² are available

1. Java's GUI components in the Abstract Window Toolkit

2. Java's lightweight GUI components in the Java Foundation Classes

Examples

The following conditional code ensures that the AWT's GUI components are available before the M-file attempts to display a Java Frame.

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

The next example is part of an M-file that includes Java code. It fails gracefully when run in a MATLAB session that does not have access to a JVM.

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

See Also

javachk

javarmpath COM Client Functions