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Core Java - Interview Questions and Answers for 'Instantiation' - 3 question(s) found - Order By Newest

 Q1. What is the difference between declaration, instantiation and initialization ?Core Java2016-05-26 14:17:48

Ans. Declaration is intimation to the compiler about the nature of Data a reference is going to hold.

For example - List myList;

Instantiation is reservation of memory.

For example

myList = new ArrayList();

Initialization or construction is setting the default values for member elements.

For example

myList = new ArrayList(mySet);

** Example 2nd is both for instantiation as well as initialization. The only difference is that 2nd will initialized the member elements to their default values whereas 3rd will initialized it with the elements from set.


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   Like      Discuss      Correct / Improve     declaration   instantiation   initialization   construction     Hewlett Packard (HP)      basic        frequent


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 Q2. Difference between object instantiation and construction ?Core Java
Anonymous
Ans. Though It's often confused with each other, Object Creation ( Instantiation ) and Initialization ( Construction ) are different things in Java. Construction follows object creation.

Object Creation is the process to create the object in memory and returning its handler. Java provides New keyword for object creation.

Initialization is the process of setting the initial / default values to the members. Constructor is used for this purpose. If we don't provide any constructor, Java provides one default implementation to set the default values according to the member data types.

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   Like      Discuss      Correct / Improve     java   oops   constructor   object instantiation


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  What are the common uses of "this" keyword in java ?
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  Why every object constructor automatically call super() in Object before its own constructors?
 What are constructors and Destructors in Java ?
  Does Constructor creates the object ?
  Can constructors be synchronized in Java ?
  Are constructors inherited? Can a subclass call the parent's class constructor? When?
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 Q3. Difference between new operator and Class.forName().newInstance() ?
Admin
info@buggybread.com
Ans. new operator is used to statically create an instance of object. newInstance() is used to create an object dynamically ( like if the class name needs to be picked from configuration file ). If you know what class needs to be initialized , new is the optimized way of instantiating Class.

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   Like      Discuss      Correct / Improve     java   oops   object instantiation   object creation   class.forname   newinstance   new operator   difference between   advanced      intermediate


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