ALLInterview.com :: Home Page            
 Advertise your Business Here     
Browse  |   Placement Papers  |   Company  |   Code Snippets  |   Certifications  |   Visa Questions
Post Question  |   Post Answer  |   My Panel  |   Search  |   Articles  |   Topics  |   ERRORS new
   Refer this Site  Refer This Site to Your Friends  Site Map  Bookmark this Site  Set it as your HomePage  Contact Us     Login  |  Sign Up                      
Google
   
 
Categories >> Software >> Java Related >> Java J2EE >> Core Java
 
 


 

 
 Core Java interview questions  Core Java Interview Questions (1721)
 Advanced Java interview questions  Advanced Java Interview Questions (331)
 Swing interview questions  Swing Interview Questions (44)
 EJB interview questions  EJB Interview Questions (134)
 Servlets interview questions  Servlets Interview Questions (255)
 Struts interview questions  Struts Interview Questions (196)
 JDBC interview questions  JDBC Interview Questions (187)
 JMS interview questions  JMS Interview Questions (9)
 SunOne interview questions  SunOne Interview Questions (3)
 J2EE interview questions  J2EE Interview Questions (71)
 Weblogic interview questions  Weblogic Interview Questions (146)
 Websphere interview questions  Websphere Interview Questions (14)
 Java Networking interview questions  Java Networking Interview Questions (20)
 Java J2EE AllOther interview questions  Java J2EE AllOther Interview Questions (87)
Question
why string constant pool in java
 Question Submitted By :: Core-Java
I also faced this Question!!     Answer Posted By  
 
Answer
# 1
String constant pool is a separate block of memory where
String object are held by JVM.
If a String object is created directly by using assignment
operator(=) as
String s1="Hello";
then it is stored in String Constant pool.
One of important characteristic of String constant pool is
that it doesn’t create same String object if there is
already in the String constant pool.

String s1 = “Hello”;
String s2 = “Hello”;

For above two String objects, JVM creates only one object
in the String constant pool and for the second string
reference variable (s2) will created, it points the string
object which is created for s1. In this case, (s1 == s2) is
true.
but when we use new operator to create object then this
object will store in heap memory.. be carefull on this.
 
Is This Answer Correct ?    23 Yes 0 No
Loknathreddy
 
Answer
# 2
To make Java more memory efficient, the JVM set aside a special area of memory called as "String Constant Pool" or "String Literal Pool".
When the compiler encounters a string literal, it checks the pool to see if an identical strong already exists or not, If not then it creates a new string literal object.
A String object is created out of the string constant pool, even if an equal already exists in the pool. Considering all that avoid new string unless you specially know that you need it.
JVM has a string pool where it keeps at most one object of any string. String literals always refers to an object in the string literal pool.
String objects created with the new string do not refer to objects in the string pool but can be made to using string's intern() method.
the java.lang.string.intern() returns an intended string, that is one that has an entry in the global string pool, then it will be added.
there is a table always maintaining a single reference to each unique object int the string literal pool ever created by an instance of the runtime in order to optimize space.
That means that they always have a reference to string objects in string literal pool. Therefore, the string objects in the string literal pool are not eligible for garbage collection.
 
Is This Answer Correct ?    1 Yes 0 No
Shabina
 
 
 

 
 
 
Other Core Java Interview Questions
 
  Question Asked @ Answers
 
can we write a program with out a class in core java? Wipro 11
What is the main functionality of Prepared Statement?   4
what is the difference between Java Command Line and C command Line?   2
how a marker interface gets its functionality and when we implements a marker interface how it got invoked Mind-Tree 3
Nullpointer exception is a very common exception. Why is it not made as a checked exception? Ness-Technologies 2
using equals method overriding which objects are compared?i.e same class objects or other class objects?Explain me.   4
What classes can be used to store arbitrary number of objects ?   1
Which One is optimal to choose ? Syncronized hash map or Hash table with single thread model? How can a hash map syncronized with out using syncrozed blocks in programm? Four-soft 3
explain about jre and jvm   2
How to decrease number of hashings in has   1
What is left shift and right shift?   1
write a program to create an vector and listeterator.and value should be enter through keyboard. Axcend 1
 
For more Core Java Interview Questions Click Here 
 
 
 
 
 


   
Copyright Policy  |  Terms of Service  |  Articles  |  Site Map  |  RSS Site Map  |  Contact Us
   
Copyright © 2013  ALLInterview.com.  All Rights Reserved.

ALLInterview.com   ::  KalAajKal.com