What is known for certain from this correct code excerpt?
ActionListener openListener = new FileOpenListener();
JMenuItem fileOpen = new JMenuItem("Open File");
fileOpen.addActionListener(openListener);
A)fileOpen will open a file dialog when clicked
B)The fileOpen menu item will be visible
C)The FileOpenListener class implements the ActionListener interface
D)The openListener object will only listen to the fileOpen object

Question

Quizplus · Accepted Answer

The code creates an instance of the FileOpenListener class and assigns it to the openListener variable. The JMenuItem fileOpen is created with the label "Open File" and an ActionListener is added to it using the addActionPerformed method. The fact that the openListener variable is an instance of the FileOpenListener class indicates that this class implements the ActionListener interface. However, nothing in the code indicates that clicking the fileOpen menu item will open a file dialog or that the menu item will be visible. The code also does not specify that the openListener object will only listen to the fileOpen object, so option D is not correct.

What Is Known for Certain from This Correct Code Excerpt