Following tests instruction says that Press "until the <Component> Demo icon has focus. Actually its not Tab key its should be Arrow key to navigate between buttons on the JToolBar.

https://github.com/openjdk/jdk/blob/master/test/jdk/javax/accessibility/manual/ButtonDemo.html#L47-#L48
https://github.com/openjdk/jdk/blob/master/test/jdk/javax/accessibility/manual/ComboBoxDemo.html#L47-L48
https://github.com/openjdk/jdk/blob/master/test/jdk/javax/accessibility/manual/OptionPaneDemo.html#L47
https://github.com/openjdk/jdk/blob/master/test/jdk/javax/accessibility/manual/TableDemo.html#L47
https://github.com/openjdk/jdk/blob/master/test/jdk/javax/accessibility/manual/TreeDemo.html#L46