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Array List Collections
What is Use of declaring an array list object like List list = new ArrayList() rather than creating object like ArrayList arr = new ArrayList();
shailesh.pandit
- Jul 11th, 2009
We may decide later to use the?LinkedList instead of ArrayList, in this situation we just need to replace the new ArrayList() part with new LinkedList() if we keep the referance variable as List interface.whereas if we keep ArrayList as the referance variable it will be cumbersome.
R.Raj
- Jul 5th, 2008
Yes,It is possible to invoke the methods of ArrayList using the reference variable list.Infact it is used for that purpose only.
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Explain interthread communication.
Radhakrishna P
- May 11th, 2009
When threads are running in shared resources we can manage the threads by using native methods (wait(), notify(), notifyAll()) from Object class.This is inter process communication between the threads while sharing shared resources
AjayMukiri
- Apr 30th, 2008
Java provides a basic set of synchronisation methods within java.lang.Object, allowing threads to wait for notification from other threads. Using the wait() and notify() methods, threads can synchroni...
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How can we call multiple applications using simple command in java
VenkitaKrishnan
- Apr 20th, 2009
Create a batch file and write down all the applications which needs to be called. Simple isn't it?
ramesh.sukka
- Apr 16th, 2009
Write Java Threading Application in which you can invoke multiple Java Application at time. so from Command promt if you execute Thead application, internally it will executed multiple application.Regards,Ramesh Sukka.
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Every application should have a main() method. Under which class does the main() method comes under?
shouvanik1979
- Mar 31st, 2009
Main() method should be present in the java class which we execute at the command prompt. for example. c:/> java abc where abc is the class which must have a main() method, because JVM calls the main method of this class after it loads all the classes into its memory.
vawani
- Nov 4th, 2008
If you are writing a program in java then you have to put main method in a class, so that class is the owner of main method but since we r declaring it as public it is available to a...
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What is Shallow cloning in Java ?
TypeEE
- Feb 11th, 2009
By default, cloning yields a shallow copy. By shallow, we mean the object is copied, but the contained objects are not. What a deep copy does it copy the cloned object, as well as all the objects with...
Naveenjavasun
- Jul 8th, 2008
When we need a copy of the object we go for cloning. When an object is shallow coned the parent object or top level object and its members are duplicated, where as the low level objects are not duplic...
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What is the basic difference between Java and .Net
akhilmisra
- Feb 8th, 2009
JAVA is platform independent while .Net works only for the MS platforms. .Net supports an array of languages while for working with J2EE you have only one option and that is 'JAVA". .Net work...
krupananda
- Jun 17th, 2008
No thats not true. Java has a byte code editor too.. Refer : http://www.cs.ioc.ee/~ando/jbe/
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How all can you free memory
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What's the difference between Object and "E"?
I'm trying to write an Iterator class for a LinkedList class that I wrote.One of the methods is "public E next()"I try to return an "E" but eclipse says "cannot convert from Object to E".How do I fix this?
kabir soni
- Feb 6th, 2009
Object is a class and E is a generic type parameter . And Iterator class alwayes return Object so to fix this problem, you need to call it. For exampleimport java.util.ArrayList;import java.util.Itera...
shishir11485
- Aug 5th, 2008
Object having a reference of one variable store in stack whereas "E" is created in a heap don't have a reference variable
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What is Externalization?
jay
- Sep 23rd, 2006
Externalization is a more advanced alternative to serialization.Basically, externalization gives you more control over serializating stream than default serialization (as by implementing Serializable ...
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Difference Between Collection and Legacy classes
What are the difference between Legacy classes and Collection other than Synchronized?
udaya.kumar
- Dec 12th, 2008
Legacy Classes : Previously Collection Frame Work was not part of java.util package. Later some of the classes were re-engineered Known as Legacy Classes. Legacy Classes are SYNCRONIZED(Ctrlng accessibility over the resource).Ex:Vector/Stack/Hashtable/Dictionary/Properties.
sampra
- Feb 11th, 2008
legacy class are syncronized by defult where as collection's member are not syncronized by deflt
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What is markup interface? What is the purpose of markup interface?
sunil_jsr123
- Aug 25th, 2008
In Java language programming, interfaces with no methods are known as marker interfaces. Marker interfaces are Serializable, Clonable, SingleThreadModel, Event listener. Marker Interfaces are implemented by the classes or their super classes in order to add some functionality.
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Supplying Arguments to Main Method
What is the meaning of supplying string[] args to main method?
dugulam
- Dec 6th, 2008
public static void main(String args[]) This array of Strings is the mechanism through which the runtime system passes information to your application. Each String in the array is called a command ...
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Difference between Byte Code and ASCII Code
Nikhil_Rathore
- Dec 4th, 2008
Byte Code is in the form of binary codes like 0/1 whether ASCII code is in the form of numeric digits which is assigned to characters and alphabets.Byte code is platform independent where ASCII codes ...
sampra
- Feb 14th, 2008
Byte code in 0/1 formate where is ascii code is given to every char is some number
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What is Difference between Event-Based Framework and Request-Based Framework?
ramesh.sukka
- Nov 26th, 2008
In Event based frameworks, process flow will happend with event triggering where as Requester based frameworks, based up on user request process flow will happend. Examples are, in Springs framework, ...
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What is the name of the java compiler used to compile the source file to a byte code?
vawani
- Nov 5th, 2008
There is no specific name for it, its only JAVA COMPILER and you can find it by the name javac.exe which you are providing the class path at the compilation or at the system properties--> Advanc...
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Why should we extend Exception instead of Throwable?
We usually extend Exception instead of Throwable. Why? In what situations we extend Throwable.Could anybody give the answer in detail. Thanks in advance.
shweta.suryanarayanan
- Oct 1st, 2008
By extending Throwable, you are giving hook for RuntimeException and programmers normally do not catch unchecked exceptions. However, if you have an app server and want to en...
rariedel
- May 27th, 2008
Extending the Exception class (a descendant of Throwable) instead of extending Throwable itself is a programming convention, not a requirement.Like most conventions, following the convention lends consistency to the end result.
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Illegal State of Exception
When does thread throws illegal state of exception?Explain with two scenarios?
mkgraumt
- Sep 27th, 2008
Any attempt to change the status after the thread has been started, throws an IllegalThreadstateException.Scenerio 1If a thread has already started and you try to call method setDaemon(boolean) on thr...
charankk
- Apr 29th, 2008
Hi,There are one scenario where we can use it as shown below.Two threads within the JVM both gain access to the same object. One thread invalidates the object and then the other thread attempts ...
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How to transfer data from one web application to another web application which are present in the same container in java?
meetpavy
- Sep 24th, 2008
This can be done by establishing URL Connection between the respective applications using java.net.URLConnection. Once connection is established requests can be wrote using ObjectOutputStream. I...
sampra
- Feb 22nd, 2008
Using the URL pattern we can transfer data from one web application to the other web application
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Command prompt argument
How to pass commandline arguments in main function through Eclipse Tools (editors).
nookashiva
- Sep 14th, 2008
Click the Run menu barNow click the Open Run DialogueA new window will be opened.In that window click the Java applications thenA new sub menu will be opened in that select Arguments menu andType the Arguments with space.Click run to view your result in the console.
Gokul44
- Jul 18th, 2008
Click the run menu barnow click the openrundialoguea new window will be opened.in that window click the arguments menu and type the arguments with space.click run to view ur result in the console.
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What is the result of expression 5.45 + "3.2"?
Core Java Interview Questions
Ans