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Interface and Abstract Class Usage
When will you use an interface and abstract class?
mani.sivapuram
- Mar 8th, 2011
the simple way we can answer is in interface we can provide only abstract methods(i.e the methods with out any implementation) and in abstract class we have abstract methods as well as concreate metho...
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Objects are sometimes referred to as __________ of a class
A) InhertienceB) InstancesC) InterfacesD) Inhibitors
kjavaid
- Mar 8th, 2011
Instances.Objects creation in Java is "Instantiating a class". Therefore the the object is an instance of the class.Best Regards,Kamil Javaid
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Object Class
When you declare a class, why does it automatically extends to object class? Give 2 reasons.
mani.sivapuram
- Mar 11th, 2011
When preparing the Java by JavaPeople they thought like every object what we prepare should have some common property so that we can do some basic operations like for example clone() method. So ...
anandkumarjha
- Aug 9th, 2010
Object class is the super class of all the classes provided by java.lang package.? And I think you know that all the basic functions to write a program like println() are the content of the class...
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Double Value
What happens when you add a double value to a String?
mani.sivapuram
- Mar 14th, 2011
Here consider String s="java"; Double d=new Double(1.4); Here when we write s="java" an object of type String is created and it is referenced to 's'.In the similar way when we write Doub...
Sarje
- Aug 20th, 2009
When you add Double value to a String first the double value will be converted to String and appended to original String and new compelet String object will be created.For exam:String str = "Ram";Double d = new Double(12.50d);str = str + d;now str is "Ram12.50"
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Are there any other 'marker' interfaces?
java.rmi.Remotejava.util.EventListener
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What is the purpose of finalization
The purpose of finalization is to give an unreachable object the opportunity to performany cleanup processing before the object is garbage collected.
lwpro2
- Mar 13th, 2011
Actually in addtion to perform some clean up process, it can also be used to bring this object to life, by making it accessible again.
sagar.singh
- Aug 23rd, 2007
Java provides a method called finalize( ) that you can define for your class. Heres how its supposed to work. When the garbage collector is ready to release the storage used for your object, it ...
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How is it possible for two String objects with identical values not to be equal under the == operator?
The == operator compares two objects to determine if they are the same object in memory. It is possible for two String objects to have the same value, but located indifferent areas of memory.
lwpro2
- Mar 13th, 2011
Normally, when define a string instance, if using, String s = "ABC"; the existing string variable at the string pool is returned. However, if using new String("ABC") there is always one additional Str...
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Import javax.swing.*;Here what is the meaning of *?
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What is the difference between throw and throws
Ahmed Safwat
- Apr 4th, 2011
form practicing java point of view , here is in brief what is the differenceyou have function that do a mathematical division and may be a a division by zero exception raises up, so you need to tell a...
Kulwant
- Sep 12th, 2005
throw is used to explicitly thorw some exception throws is used to tell the compiler the this method might through mentioned type of exception.
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Primitive Types
What happens when you add a primitive type (e.g. double) value to a collection?
pdureja
- Apr 6th, 2011
Collection can hold Objects but not primitives. Prior to Java5, we need to wrap primitive using wrapper classes and in java 5 autoboxing do it automatically.Prior to java 5:xyzCollection.add(new Integer(10))In javaxyzCollection.add(10) //will do autoboxing
mani.sivapuram
- Mar 11th, 2011
Every one says that every concept in Java is purely prepared in Object Oriented Form only in you need to remember one thing when Java people preparing the Java they try to create an alter native t...
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What is the difference between string and string buffer?
Tarun Wadhwa
- Sep 8th, 2008
Strings are immutable objects means you cannot modify the instance. For example when you create one instance of string and you are changing the value of string, it does not mean that you are changing ...
srinivaspulla
- Sep 7th, 2008
Java provides the StringBuffer and String classes, and the String class is used to manipulate character strings that cannot be changed. Simply stated, objects of type String are ...
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What is the difference between a MenuItem and a CheckboxMenuItem
The CheckboxMenuItem class extends the MenuItem class to support a menu item thatmay be checked or unchecked.
Ashwinshenoy7
- May 9th, 2011
For understanding purpose,Menu Item and check box menu items could be considered as classes.Menu item is a parent class, check box menu item is a sub class(child class) that inherits from the menu ite...
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What is the differance between equals() method and ==
Balrog
- Jan 31st, 2007
Your'e WRONG!!
String s1 = "hello";
String s2 = "hello";
is s1 === s2? TRUE
This is because SAME literals have the same reference in memory!!!
Don't post incorrect response.sitaram81581
- May 22nd, 2006
The operator '==' checks whether or not two variables ( both primitive like 'int' variable and reference variables like 'String' variable) contain same data. In case of objects, reference variables co...
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WHAT IS THE DIFFERENCE BETWEEN MULTI-THREADING AND MULTI-PROCESSING?
kazi_latiful
- May 23rd, 2011
Multi processing is term that multi program can execute with multi processor that can share the same physical memory space.on the other hand multi-threading is that different program can execute on different time on simultaneously that can share same memory address space.
Vara Rama Krishna Chadaram
- Aug 7th, 2006
MULTI-THREADING :
It refers to the ability of the operating system to execute multiple parts of a process simultaneousliy.
MULTI-PROCESSING:
It refers to the ability of the operating system to execute multiple programs simultameously .The process time is shared between the programs.
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Use of static,final variable
Mohan Raja Gadikota
- May 31st, 2011
Static : Move the variable/methods/class during HDD to RAM. ie; they are available without instantiating the class, by creating an object of that class nd access its methods,members.Final : for Preventing the inheritance further ie; the class with final word as prefix cannot be extend further!
muralidhar.9e
- Nov 23rd, 2010
static variable allocates the memory as globally.It won't reallocate the memory while running.It initializes the memory for the variable only once.final variable tells the variable is final means ...
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What is the difference between Abstract class and Interface
Answered by Scott on 2005-05-12 10:03:06: An abstract class can contain non-abstract methods which do not have to be overridden in the subclass. There is no difference between a fully abstract class (all methods declared as abstract and all fields are public static final) and an interface.
harihb
- Jun 2nd, 2011
Versioning and default functionality.Let's say that you have an abstract class called Human with a functionality walk(). Person A, B that extends abstract class gets the default functionality '...
purva15
- Sep 24th, 2009
A abstract class define both abstract and non abstract methods but interface can have only abstract methods.
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What is the difference between final, finally and finalized
kgopalakrishna
- Jun 9th, 2011
Final:final is the constant ;finally:'finally is the key word.this is is ?finally block is doing free from errors.?
jagadish kumar ch.
- Jul 13th, 2005
final is used for declaring a variable as a constant, final class can't be inherited, final methods cannot be overloaded but overridden finally statement should execute not depending upon ...
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Which Collection class is used for FIFO in Java
Guest
- Mar 21st, 2005
Java.util.Concurrent ( Queues)
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What is the diffrence between an Abstract class and Interface
Sujit4175
- Jun 23rd, 2011
As far as difference is concerned, then the only difference between interface and Abstract class is:?In the interface we can only declare a method, we can not define it within interfaceBut in the abs...
Vijay Chaudhary
- Jul 31st, 2005
Variables declared in Interface are static and final by default.
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