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What is the difference between tomact and weblogic
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What is abstraction?
sujatham
- Jul 31st, 2007
An abstraction denotes the essential properties and behaviors of an object that differentiate it from other objects. The essence of OOP is modelling abstractions, using classes and objects.
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Why cant we compare two objects with ==,why we should use only .equals() for objects.
we can compare two Strings with (==) when we assign some string value to the String variable,but if we create an object to that strings and compare eachother we cant use(==) operator ,because we can compare only values with(==) operator but as Objects contains references to that variables we cant use(==) operator,hence .equals() is used on references and (==) is useed on values
geeksterrahul
- Jul 25th, 2009
== operator checks to see if two references are referring to the same location on memory.This is also called shallow comparison..equals checks to see if the two objects match each other. This is also known as deep comparison.
chandanareddy
- Jan 31st, 2006
Both == and equals() can be used to compare objects but in different aspects== is used to check whether the references are aliases.equals() is used to check for object value equality. equals() method...
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What is collection framework?what interfaces and classes support collection framework?
One can use different groups of objects in program using collection frame work.for more detail readcollection frame work from java.util pack.
sampra
- Mar 7th, 2012
Collection framwork is the concept to store the data. there are mainly two part in collection framework1. collection interface 2.Map interface
1.Collection-List/Set--AL/LL/Vector(C) Set (Ash set/linked hashset/Tree set)
2.Map- hash map/hashtable/tree map/linked hashmap(C)soorma
- Apr 26th, 2006
A collection is a group of object. its provide ways (using classes n interface)for fundamental alteration in the structure and architecture of many element in java.util pakageclasses>>>...
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If interface & abstract class have same methods & abstract class also not contain any implementation for those methods which one you prefer ?
Use abstract class because we implement only requried methods of abstract class but for interface we must implement all methods whether or requried or not
msarada
- Aug 24th, 2006
if we want to have all the other properties of the abstract class along with the unimplemented methods, then we prefer an abstract class otherwise we go for an interface(in order to have multiple inheritance).
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Why default constructor of base class will be called first in java?
santukt
- Apr 15th, 2006
Simply bcoz in real world in order to construct a new thing based on another what we will construct first.Remenber The rule is no only applicable to default constructor but to parameterised constructor also.
vmshenoy
- Jan 21st, 2006
whenever v create an object of child class ,automatically an obj of parent class is also created,with this what i mean is that data members of base class also accessible ,provided access specifi...
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What is the difference b/w Iterator & ListIterator
Iterator : Enables you to cycle through a collection,obtaining or removing elementsListIterator :It extends Iterator allow bidirectional traversal of list & the modification of element
sampra
- Mar 13th, 2012
Iterator : Enables you to cycle through a collection,obtaining or removing elements
ListIterator :It extends Iterator allow bidirectional traversal of list & the modification of element
lakshmijs433
- Sep 5th, 2011
Iterator is used to traverse map set and list where list iterator is used to traverse only Lists
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As the Swings have more advantages over the AWT.. Why still in market are they using AWTs??plzz..i want answer..in many interviews they asked me the same.
srilatha249
- May 30th, 2007
Why are will still using awt if swings has more advantages than awt.are there any specific features in awt that are not present in swings
takumar
- Aug 2nd, 2006
since swings is even developed on the top of awt for example we have jbutton which is similar to button in awti.e; swings package is related to awt
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Can array with zero length exist in Java?
swapnil
- Sep 17th, 2013
Yes, array size in java is always 0 bz array is start with 0th location
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Why was Java Created?
PlatForm Indepentdent ,security,Garbage Collection.
nishant.mca2010
- Dec 17th, 2010
Java was created to make programming simple and easy. Designing the Java simple was the main aim of the Java creator (Java Soft people). When Java was developed, they wanted it to be simple because i...
jimmy514in
- Apr 22nd, 2010
Java is created for simple OOP.It doesnt use multiple inheritance for simplicity hence it is not pure OOP.Java uses JVM, hence it is platform independent.Java uses collections hence it is easy to code...
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Explain run time , complile time in terms of polymophism
santh kumar
- Dec 19th, 2006
To say more clearly, After compilation,JVM takes byte code of resource(Proramme). At that time it doesnt know which method is called by which object. In the case of Overloading, JVM knows which m...
hi_goura
- Dec 4th, 2006
Polymorphism mean "One name, different work" and when this is applied on methods, we are having to versions of usingthe same method name with different functionality. They are "Method Overloading" and...
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Can we create a class in a method if it is possible how to access that class?
dileep
- Jan 24th, 2007
You can create a class in a method as a normal way.That type of classes are known as "Method Local Inner Class". You can access the member variables as well as the methods of your Outer Class.You can ...
santh kumar
- Dec 19th, 2006
See the following code: public class InnerClassEx { public void test(int a) { final int p=a; final class X { public void a() { System.out.println("it's statement from inner class:...
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What is the Difference between Runtime and RunTime java API's?
Vibs
- May 17th, 2007
You can writepublic static void main(String a[]) { Runtime rt = Runtime.getRuntime(); System.out.println("result::"+rt); try {rt.exec( "notepad.exe"); } catch (IOException e) { // TODO A...
santh kumar
- Dec 14th, 2006
Runtime is one of classes in Java and it's super class remains same as we know(java.lang.Object). A java Programme can have only a single instance of this class "Runtime". that means, Runtime rt = ...
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HiRecently at an interview I was asked the following question:Create a hashtable A, assign key value pairs to it and then set A to null. Will it be garbage collected?Please reply.
jimmy514in
- Oct 31st, 2010
Objects which have null references are garbage collected ..But you can just request the garbage collector algo to start..you cannot command it..so when it would be collected is not known..Also, a null reference attached to object is called as weak referenceAnd weak references are garbage collected.
vinaymudgil007
- Jun 11th, 2008
Yes the hashtable would be avaliable for garbage collection BUT when actually is would be collected that would depend on JVM garbage collection cycle.vinny
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What are the difference between java.sql package and javax.sql package
vijay
- May 18th, 2012
Javax.sql provides connection pooling ,distributed transaction,disconnected rowsets
sampra
- Feb 15th, 2008
Java.sql.* package is used for the basic jdbc connections.javax.sql.* package is used for the advance jdbc. Advance is connection pooling, rowsets...ect.
Core Java Interview Questions
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