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Core Java
What is difference between Core Java and Advance Java?
sapanindia
- Aug 17th, 2010
The fundamentals conepts of java which deals basically with OOPs concepts and their implementation in language can called core java1. Other word is called java application2. Core Java is stand alone a...
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Constructor Call
How can we call a constructor through another constructor in the same class?
chetan.nellekeri
- Aug 25th, 2010
There is no way to invoke a constructor explicitly.Respective constructor is invoked only at the creation of object.For Ex: Hello h=new Hello(); // This will invoke default constructor if exists Hello...
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Size of an Object
How to find size of an object?
rohodium
- Sep 7th, 2010
As there is no predefined method in Java. We can use an indirect approach. We can calculate the memory of an object by taking the difference of the amount of memory used by the program before creatin...
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Difference between Vector and ArrayList?
pyasodha
- Sep 8th, 2010
1) Synchronization - ArrayList is not thread-safe whereas Vector is thread-safe. In Vector class each method like add(), get(int i) is surrounded with a synchronized block and thus making Vector class...
sun
- Oct 4th, 2005
As vector is synchronized class so execution wil be slower then arraylist,but that will be thread safe.arraylist execution fast but not thread safe.
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Why do we need a finalze() method when Garbage Collection is there
majisukumar
- Sep 8th, 2010
By using finalization,we can define specific actions that will occur when an object is just about to reclaimed by the Garbage Collector.e.g - If an object is holding some nonjava resources such as fil...
meenama
- Apr 30th, 2008
We need not call the finalize() method directly. The method is called automatically by the garbage collector when it determines no more references to the object exist. But when we need to cl...
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When a thread is created and started, what is its initial state
A thread is in the ready state after it has been created and started.
rooma singh
- Sep 9th, 2010
Thread is a process which is call by some component eg in web development, container creates a thread (of service() function) and initialised it by giving appropreate input or arguments.
muralidhar.9e
- Sep 8th, 2010
A thread always having some states after creating.They are:NewRunnableRunningBlockedDeadCreating a thread using New keyword a new thread will create.After it started to run at that movement a th...
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Runnable Interface
Why we are using by implementing the runnable interface rather than we have the run() method in Thread class?
pdommara
- Sep 28th, 2010
Hi, Is the question : Why we are going to Runnable interface when you have Thread class ?. Then every java basic developer should know that " Java does n...
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Have you ever used HashTable and Dictionary
Pattukkottai Arun
- Jul 22nd, 2005
Yes.
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Runnable Method
If Thread class contains run() method then why we are using run() method by implementing the runnable method in the Thread?
muralidhar.9e
- Sep 29th, 2010
Actually Runnable interface has the method run(). Every thread Object call the start() method to run the thread run() method. So Every run() method have their own implimentation.So we should write their own run() method thread code.
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What are the OOPS concepts in Java
praju86
- Sep 26th, 2010
Inheritance is one of the concepts which makes Java an OOP language. Two other important features are 1.POLYMORPHISM-concept which permits "single interface, multiple functionalities". 2.ENCAPSULAT...
Gupta Pravin Kumar
- Oct 6th, 2006
INHERITANCE: Inheritance is the process by which one object can acquire the properties of another. The best example for this is C,C++, and JAVA languages itself. Java is being derived from C++ which...
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Why is transient modifier used and where in real life?
Many people disturbed me about the solution,some one help me.
anandkumarjha
- Oct 3rd, 2010
Volatile modifier is being used in the field of multithreading because whenever all the threads access to a single variable ,they have their seperate copy of that variable and if they modifies the var...
Raja Chaithanya Bangaru
- Nov 11th, 2005
In Java, all objects are not serializable.In distibuted environment,an object needs to be serializable.(serialization means writing the state of an object to a file using output stream so that it pers...
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Need of Method Overloading
What is the need of method overloading? What would happen if this feature is not present in Java?
msrmsr
- Oct 4th, 2010
In Java one of the main concept is polymorphismpoly means many..taking many form with existing one.if we use a method callled add();add(int x,int y) we can? add 2 integersadd(float x,float y)we can a...
yogesh249
- Jan 30th, 2010
It is simple. Overloading is required, if you want a particular method to change its behavior based on the parameters passed.Suppose you have a sum functionSum(int i, int j)This will add two inte...
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Why would I want to make a class final? Doesn't that defeat the whole purpose of OO?
pdommara
- Oct 6th, 2010
If you are sure on that behaiour of your class and sure that no one from outside world should not change the its behaviour, then you can make the class as final. Thats why java have String class as final why bcas java authors dont want to change its bahaviour.
Deepak Sharma
- Dec 22nd, 2006
exactly, it is used only for encapsulation for hiding the information.eg.. string class is also defined as final..if u want to see more than see the rt.jar in which all the classes are defined in jdk141_05jrelibrt.jar.thanx and regardsDeepak Sharma
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Vector Size
What is the default size of Vector
yogesh249
- Oct 26th, 2010
Default size of vector is 10.Source:?http://download.oracle.com/javase/1.4.2/docs/api/java/util/Vector.html
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Jbutton is Swing is equivalent to ______ in AWT
Skill/Topic: AWT & AppletsA) Button
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What is the difference between native and abstract
What is the difference between native and abstract?can we declare a method as native inside an interface?if yes then why? if no then why not?
abinaya .g.p
- Nov 13th, 2010
No, because interface is by default is a abstract class and can contain only abstract methods and final or static variables, thus it cannot contain concrete methods and instant variables.
Sunil Pratap Singh
- Nov 14th, 2006
Native keyword is prefixed with method name when we want that method to be implemented using a native language like c and c++. So in the class we only declare the method and the defination of the meth...
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What happens if a try-catch-finally statement does not have a catch clause to handlean exception that is thrown within the body of the try statement
The exception propagates up to the next higher level try-catch statement (if any) orresults in the program's termination.
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Static Import
What is a static import? Why it is required?
venkat9060
- Nov 23rd, 2010
By using the static import we can reduce the code writing for example static import java.lang.System class StaticTest{ &nbs...
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