Core Java Interview Questions 1 What is the difference between an Abstract class and Interface?

187) What is a compilation unit?
A compilation unit is a Java source code file.
188) What interface is extended by AWT event listeners?
All AWT event listeners extend the java.util.EventListener interface.
189) What restrictions are placed on method overriding?
• Overridden methods must have the same name, argument list, and return type.
• The overriding method may not limit the access of the method it overrides.
• The overriding method may not throw any exceptions that may not be thrownby the
overridden method.