1. What is a transient variable?
A transient variable is a variable that may not be serialized.
2. Which containers use a border Layout as their default
layout?
The window, Frame and Dialog classes use a border layout as
their default layout.
3. Why do threads block on I/O?
Threads block on I/O (that is enters the waiting state) so
that other threads may execute while the I/O Operation is
performed.
4. How are Observer and Observable used?
Objects that subclass the Observable class maintain a list
of observers. When an Observable object is updated it invokes
the update() method of each of its observers to notify the
observers that it has changed state. The Observer interface is
implemented by objects that observe Observable objects.
5. What is synchronization and why is it important?
With respect to multithreading, synchronization is the
capability to control the access of multiple threads to shared
resources. Without synchronization, it is possible for one
thread to modify a shared object while another thread is in the
process of using or updating that object's value. This often
leads to significant errors.
6. Can a lock be acquired on a class?
Yes, a lock can be acquired on a class. This lock is
acquired on the class's Class object.
7. What's new with the stop(), suspend() and resume() methods
in JDK 1.2?
The stop(), suspend() and resume() methods have been
deprecated in JDK 1.2.
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