java/awt/Frame/MiscUndecorated/RepaintTest.java is supposed
to test the rendering of AWT and Swing Button and TextField

But due to a copy / paste error it only tests the Buttons - and tests them twice
See this code
        passed = paintAndRepaint(button, (swingControl? "J": "")+"Button");
        if( !paintAndRepaint(button, (swingControl? "J": "")+"TextField") ) {

The first param to the second call should be "textField"