All About JAVA

How many bits are used to represent Unicode, ASCII, UTF-16, and UTF-8 characters?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:35:00 +0000

Unicode requires 16 bits and ASCII require 7 bits. Although the ASCII character set uses only 7 bits, it is usually represented as 8 bits. UTF-8 represents characters using 8, 16, and 18 bit patterns. UTF-16 uses 16-bit and larger bit patterns.

Which method of the Component class is used to set the position and size of a component?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:35:00 +0000

setBounds()

What is the difference between the >> and >>> operators?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:34:00 +0000

The >> operator carries the sign bit when shifting right. The >>> zero-fills bits that have been shifted out.

What is an Iterator interface?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:34:00 +0000

The Iterator interface is used to step through the elements of a Collection.

What modifiers may be used with an inner class that is a member of an outer class?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:33:00 +0000

A (non-local) inner class may be declared as public, protected, private, static, final, or abstract.

What is the Vector class?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:33:00 +0000

The Vector class provides the capability to implement a growable array of objects.

How does Java handle integer overflows and underflows?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:33:00 +0000

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 List interface?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:32:00 +0000

The List interface provides support for ordered collections of objects.

which characters may be used as the second character of an identifier, but not as the first character of an identifier?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:32:00 +0000

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 are the Collections API?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:31:00 +0000

The Collections API is a set of classes and interfaces that support operations on collections of objects.

What state does a thread enter when it terminates its processing?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:31:00 +0000

When a thread terminates its processing, it enters the dead state.

Which containers use a FlowLayout as their default layout?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:31:00 +0000

The Panel and Applet classes use the FlowLayout as their default layout.

What method is used to specify a container's layout?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:30:00 +0000

The setLayout() method is used to specify a container's layout.

What is the preferred size of a component?

noreply@blogger.com (Educational Information) — Sat, 10 May 2008 09:29:00 +0000

The preferred size of a component is the minimum component size that will allow the component to display normally.

Is null a keyword?

noreply@blogger.com (Educational Information) — Fri, 18 Apr 2008 10:58:00 +0000

The null value is not a keyword.

What's new with the stop(), suspend() and resume() methods in JDK 1.2?

noreply@blogger.com (Educational Information) — Fri, 18 Apr 2008 10:57:00 +0000

The stop(), suspend() and resume() methods have been deprecated in JDK 1.2.

Can a lock be acquired on a class?

noreply@blogger.com (Educational Information) — Fri, 18 Apr 2008 10:57:00 +0000

Yes, a lock can be acquired on a class. This lock is acquired on the class's Class object.

What is synchronization and why is it important?

noreply@blogger.com (Educational Information) — Fri, 18 Apr 2008 10:57:00 +0000

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.

How are Observer and Observable used?

noreply@blogger.com (Educational Information) — Fri, 18 Apr 2008 10:56:00 +0000

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.

Why do threads block on I/O?

noreply@blogger.com (Educational Information) — Fri, 18 Apr 2008 10:56:00 +0000

Threads block on i/o (that is enters the waiting state) so that other threads may execute while the i/o Operation is performed.

which containers use a border Layout as their default layout?

noreply@blogger.com (Educational Information) — Fri, 18 Apr 2008 10:55:00 +0000

The window, Frame and Dialog classes use a border layout as their default layout.

what is a transient variable?

noreply@blogger.com (Educational Information) — Fri, 18 Apr 2008 10:54:00 +0000

A transient variable is a variable that may not be serialized.

JAVA

noreply@blogger.com (Educational Information) — Tue, 08 Apr 2008 04:07:00 +0000

"Java" generally refers to a combination of three things: the Java programming language (a high-level, object-oriented programming language); the Java Virtual Machine (a high-performance virtual machine that executes bytecodes on a specific computing platform, typically abbreviated JVM); and the Java platform, a JVM running compiled Java bytecodes, usually calling on a set of standard libraries such as those provided by Java Standard Edition (SE) or Enterprise Edition (EE). Though coupled by design, the language does not imply the JVM, and vice versa.