Given： What is the result？（）
Given： When line 14 is reached， how many objects are eligible for the garbage collector？（）
Given： Which three changes should be made to adapt this class to be used safely by multiple threads？（）
Given： Which statement is true？（）
Given the following six method names： add Listener add Mouse Listener set Mouse Listener delete Mouse Listener remove Mouse Listener register Mouse Listener How many of these method names follow JavaBean Listener naming rules？（）
