From Documentation
zscript can access UI component by ID, in the following example,
<window id="win_1"> <zscript><![CDATA[ win_1.title="given by zscript"; ]]> </zscript> </window>
the result will be:
given by zscript
To access ui component in java code, you can use Path.getComponent() to obtain the mapping java object.
Window win = (Window)Path.getComponent("/win_1");
win.setTitle("given by java");