User`s manual

5 Calling Java from MATLAB

5-12

Note Typically, you will not need to use javaObject. The default MATLAB

syntax for instantiating a Java class is somewhat simpler and is preferable for

most applications. Use

javaObject primarily for the two cases described

above.

Java Objects Are References in MATLAB

In MATLAB, Java objects are references and do not adhere to MATLAB

copy-on-assignment and pass-by-value rules. For example,

origFrame = java.awt.Frame;

setSize(origFrame, 800, 400);

newFrameRef = origFrame;

In the second statement above, the variable newFrameRef is a second reference

origFrame, not a copy of the object. In any code following the example above,

any change to the object at

newFrameRef also changes the object at origFrame.

This effect occurs whether the object is changed by MATLAB code, or by Java

code.

The following example shows that

origFrame and newFrameRef are both

references to the same entity. When the size of the frame is changed via one

reference (

newFrameRef), the change is reflected through the other reference

(

origFrame), as well.

setSize(newFrameRef, 1000, 800);

getSize(origFrame)

ans =

java.awt.Dimension[width=1000,height=800]

Concatenating Java Objects

You can concatenate Java objects in the same way that you concatenate native

MATLAB data types. You use either the

cat function or the square bracket

operators to tell MATLAB to assemble the enclosed objects into a single object.