Questions in Core Java 1
What is a transient variable?
A transient variable is a variable that may not be serialized.
Which containers use a border Layout as their default layout?
The window, Frame and Dialog classes use a border layout as their default
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.
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
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.
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.
What's new with the stop(), suspend() and resume() methods in JDK
The stop(), suspend() and resume() methods have been deprecated in
Is null a keyword?
The null value is not a keyword.
What is the preferred size of a component?
The preferred size of a component is the minimum component size that
will allow the component to display normally.
What method is used to specify a container's layout?
The setLayout() method is used to specify a container's layout.
Which containers use a FlowLayout as their default layout?
The Panel and Applet classes use the FlowLayout as their default layout.
What state does a thread enter when it terminates its processing?
When a thread terminates its processing, it enters the dead state.
What is the Collections API?
The Collections API is a set of classes and interfaces that support
operations on collections of objects.
Which characters may be used as the second character of an identifier,
but not as the first character of an identifier?
The digits 0 through 9 may not be used as the first character of an
identifier but they may be used after the first character of an identifier.
What is the List interface?
The List interface provides support for ordered collections of objects.
How does Java handle integer overflows and underflows?
It uses those low order bytes of the result that can fit into the size
of the type allowed by the operation.
What is the Vector class?
The Vector class provides the capability to implement a growable array
What modifiers may be used with an inner class that is a member of
an outer class?
A (non-local) inner class may be declared as public, protected, private,
static, final, or abstract.
What is an Iterator interface?
The Iterator interface is used to step through the elements of a Collection.
What is the difference between the >> and >>> operators?
The >> operator carries the sign bit when shifting right. The >>> zero-fills
bits that have been shifted out.
More Jobs Interview Questions
Questions in Core Java 2
Interview - Preparation Questions
Do you have a Java Problem?
Ask It in The Java
Certification, Programming, JavaBean and Object Oriented Reference Books
Return to : Java Programming Hints
All the site contents are Copyright © www.erpgreat.com
and the content authors. All rights reserved.
All product names are trademarks of their respective
The site www.erpgreat.com is not affiliated with or endorsed
by any company listed at this site.
Every effort is made to ensure the content integrity.
Information used on this site is at your own risk.
The content on this site may not be reproduced
or redistributed without the express written permission of
www.erpgreat.com or the content authors.