Educational Questions & Answers

Sample Interview Questions For Core Java

Dear Visitors herewith we are listing some sample expected questions asked during Interview Sessions. This Questions is only for your references. Refer the suitable books and prepare the answers for this questions for your satisfaction.

Why Java is not 100% pure object oriented language?

Explain working of Java Virtual Machine (JVM)

why java does not support Multiple Inheritance?

When we are sending the serialized array object thro the network, what is being passed ? is the value or the reference ?

JVM is platform independent/dependent?why? 2) which one is faster in execution Array List or Array? why?

When you have an object passed to a method and when the object is reassigned to a different one, then is the original reference lost

What is heap in Java

Can a method be static and synchronized

Will there be a performance penalty if you make a method synchronized? If so, can you make any design changes to improve the performance

What is MVC architecture

What are interfaces? or How to support multiple inheritance in Java?

Difference: Java Beans, Servlets

Why java does not support Multiple Inheritance?Why java is not pure Object Oriented?

What is the Difference between Design Pattern and Architecture?

How an Hashtable can change the iterator? Can a HashMap change the iterator?

What is phantom memory

In Java, how are objects / values passed around

What is EJB

How would you implement a thread pool

What design patterns have you used

How to use C++ code in Java Program?

Difference: AWT, Swing

How do i upload a file from client side to server side using servlet and jsp this will happen when I click upload button on web-page?

How can we take various inputs from user as int,char,string,float etc ?

What are the different kinds of exceptions? How do you catch a Runtime exception

Do primitive types have a class representation

What are the differences between C++ and Java

How does serialization work

What are the differences between ArrayList and a Vector

Disadvantages of Java

Explain the importance of "static"keyword

It is a saying that static methods in JAVA programs should be minimised. What is the reason for this? any problems arise or there is any performance measures to be looked into it.

Why multiple inheritance using classes is disadvantage in java

What are the differences between JIT and HotSpot

How all can you free memory

How can you do multiple inheritance in Java

How does garbage collection work

How would you declare a SingleThreaded servlet

What is the interface of thread?

What is BYTE Code?

Whether a Class,Method can be garbage collected or not?How?

Give example of : High severity & Low priority

Write a program that singleton objects returns two instances?

What is a memory footprint? How can you specify the lower and upper limits of the RAM used by the JVM? What happens when the JVM needs more memory

Does java do reference counting

What is data encapsulation? What does it buy you

What are the differences between AWT and Swing

How are memory leaks possible in Java

How can you swap two variables without using a third variable?

Whether private,protected method can be overloaded,overrided or not?

What do you meant by private constructor? why somebody declare only private constructor.

Does JVM maintain a cache by itself? Does the JVM allocate objects in heap? Is this the OS heap or the heap maintained by the JVM? Why

What does a static inner class mean? How is it different from any other static member

How would you pass a java integer by reference to another function

What are the differences between EJB and Java beans

How can u move/drag a component placed in Swing Container?

Does Java have "goto"?

Why ArrayList is faster than Vector?

Is java a fully object oriented programming or not? if not why?

Whether we can set the time implicitly for the garbage collection?

What are the disadvantages of reference counting in garbage collection

How do you declare constant values in java

What is reflection API? How are they implemented

How would you keep track of a session

What are STRUTS

What is the purpose of interface? And tell the difference between the class and interface?

What is the meaning of "final" keyword?

Meaning - Abstract classes, abstract methods

What is the basic difference between Java and .Net

Write program for single objects returns two instances?

Is it advisable to depend on finalize for all cleanups

How all can you instantiate final members

What is the primary advantage of XML driven Java Beans

Explain the keywords - native, transient, volatile, finally

Explain Servlet and JSP life cycle

Can I create final executable from Java?

Difference ? Java, C++

What is the difference between an object and an instance? And give me a real time example to differentiate these two?

When you use a struts framework, where would you place your business logic

How is serialization implemented in Java

What are the primitive types in Java

Differences between HashList and HashMap, Set and List

What would happen if you say this = null

Explain Garbage collection mechanism in Java

Explain Java security model

How hashtable is synchronized?why hashmap is not synchronized? Can we make hashmap synchronized?

Can we declare multiple main() methods in multiple classes.ie can we have each main method in its class in our program?

Is there a separate stack for each thread in Java

What is the sweep and paint algorithm

What do you like most with Ant

Sample Interview Questions For Core Java

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