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Wrapping an Object
What does "wrapping" an object mean?
SreerangKulkarni
- Oct 29th, 2009
When an object A is said to "Wrap" object B, it means that Object A HAS A reference to the Object B and deligates calls to it.
karthik_knight2000
- Dec 3rd, 2008
Wrapping an object means we are covering that object, say for example? in Java we can say?String is a class as well as?String is a data type.String s;?? // here s is object of String class ???...
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What is the use of interface in realtime java project ?
Manjunath_7_89
- Mar 25th, 2016
Interface is majorly supported for IS-A relationship ie; Inheritance. Writing an interface is similar to writing a class. But a class describes the attributes and behaviours of an object. And an inter...
meena
- Feb 16th, 2016
Consider a construction of a building. The basic entire PLAN of the building I what an INTERFACE does. Next, the implementation of that PLAN is done by CONCRETE methods. If some of the work is done and still some is left is what ABSTRACT method/class does.
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What would happen if you say this = null
ajkush
- May 6th, 2009
If the value is null or zero, the difference is simple as difference between I know and I dont know.Null means I dont know the value and zero means I know the value.
ashokkumar
- Jan 25th, 2007
[root@tm1 classes]# javac -d . ../../../src/com/tm/slynx/util/AuditLogBean.java../../../src/com/tm/slynx/util/AuditLogBean.java:47: cannot assign a value to final variable thisthis = null;^1 error
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How does serialization work
Sarje
- Aug 28th, 2009
In serialization process first state of the object is written to the java.io.ObjectOutputStream using its writeObject() method.Then this ObjectOutputStream writes the state of the object to the java.i...
sampra
- Feb 14th, 2008
It convert data object into flat format and transfer it any other remote mechine by any medum and thn there reconstruction of object will be done
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How would you pass a java integer by reference to another function
Mayank
- Mar 13th, 2018
I don't think that is right because if it was then changing the value inside the called function should reflect the change when the passed variable is accessed in calling function.
sourabharvikar3
- May 4th, 2011
what is point behind sending integer by reference???Still if you want to do so... lookclass Demo{private int i;public static void main(String[] ar){ Demo d=new Demo();&nb...
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Can HashMap store null values?If yes, how many and in which one?
vikas singh
- Dec 23rd, 2006
hi your ans is too good.........
santh kumar
- Dec 13th, 2006
I entered clearly. with spaces and next lines.Why i'm getting data collabarated? it is not easy to read. any suggestions would be appreciated. what should i do to be in the same format exactly how i entered. with regards, santh
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Restrict a Class
How can we restrict a class so that no instance creation of class possible without declaring the class as Abstract ?
Sarje
- Aug 18th, 2009
Only abstract classes can not be instantiated. If you make the constructor private then you can not instantiate it outside of the class but you can still instantiate it within the same class.
sriragv
- Jun 21st, 2009
1. By creating a private constructor2. By giving abstract key word to the class
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Can a method be static and synchronized
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Answered by: Srimant Misra
- Aug 12th, 2005
A static method can be synchronized. If you do so, the JVM will obtain a lock on the java.lang.Class instance associated with the object. It is similar to saying:
synchronized(XYZ.class)
{
}Akii
- May 21st, 2013
If you synchronized on static method ,its lock on class level not only that method.
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How all can you free memory
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Tell me the differences between enumeration and iteration?Which can use where in realtime?
javabuddy
- Jan 10th, 2011
Between two Enumeration is older and its there from jdk 1.0 while iterator was introduced later. The functionality of Enumeration interface is duplicated by the Iterator interface. Iterator has a rem...
chandaka
- Sep 22nd, 2009
The functionality of this interface is duplicated by the Iterator interface. In addition, Iterator adds an optional remove operation, and has shorter method names. New implementations should consider using Iterator in preference to Enumeration.
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In which class public static void main(String ar[]) is declard in java
sat.beit
- Jun 6th, 2008
Main method define in class from which excution of the application will get start.Which u can called main class of the file and file name will be the same as mainclass.
dvs198528
- Jun 6th, 2008
Public static void main(String ar[]) is in the class whose name is same as the name of the program name.Reason : To start the execution of the program initiating from main().
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What is the difference between String and StringBuffer? Which is better to use in project?
mani.sivapuram
- Apr 14th, 2011
String is a immutable.What is immutable the state of an object is not changed if we initilize once.i.e for example String s1="Geek" ...
sankarsansinha
- Feb 5th, 2009
String objects are constants and immutable where as StringBuffer objects are not.StringBuffer Class supports growable and modifiable string where as String class supports constant strings. Strings onc...
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What is the difference between String and StringBuffer?
sampra
- Feb 22nd, 2008
One majar diff also is string obj are immutable where as string buffer objects are mutable
paddu
- Oct 12th, 2007
Strings are immutable that means we cann't change the content or data. Where in the case of StringBuffer we can change the data or content that are presented in that.
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Object Creation
In how many ways we can create an object? Explain with example.
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vishrutha- Member Since Feb-2009 | Feb 13th, 2009
1. Using new keyword
This is the most common way to create an object in java. I read somewhere that almost 99% of objects are created in this way.MyObject object = new MyObject();
2. Using Class.forName()
If we know the name of the class & if it has a public default constructor we can create an object in this way.MyObject object = (MyObject) Class.forName("subin.rnd.MyObject").newInstance();3. Using clone()
The clone() can be used to create a copy of an existing object.MyObject anotherObject = new MyObject();
MyObject object = anotherObject.clone();4. Using object deserialization
Object deserialization is nothing but creating an object from its serialized form.ObjectInputStream inStream = new ObjectInputStream(anInputStream );
MyObject object = (MyObject) inStream.readObject();5. Using class loader
one more is through creation of object using classloader likethis.getClass().getClassLoader().loadClass(com.amar.myobject).newInstance();
Now you know how to create an object. But its advised to create objects only when it is necessary to do so.
sampra
- Mar 13th, 2012
There are 5 ways:
1-> new operaotor
2-> Class.forName()
3-> Cloning
4-> Deserialization
5-> Class.newInstance()Max
- Sep 7th, 2011
All sorts of syntax sugar can also be named: 6. New String as a result of concatenation: String varName = getClass().getName(); //to avoid compile-time optimization String a = "Prefix" + varName; ...
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Abstract Class or Method
Can we make use of "this" keyword reference inside a abstract method or abstract class? Explain
java indian
- Mar 10th, 2010
Yes we can use "this" key word in Abstract class or methods,Here we have simple sample used of this key in abstract.abstract class ab { int j;void meth() { this. j=10; ...
yogesh249
- Jan 24th, 2010
Yes that is true that we cannot create object of an abstract class. But the question is "Can we use this keyword in an abstract class."The answer is YES we can..Have a look at the following ...
Core Java Interview Questions
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