Interview Questions and Answers for 'Expert' | Search Interview Question

Interview Questions and Answers - Order By Newest

Q61. How can we catch an exception thrown by another thread ?

Core Java

Ans. http://stackoverflow.com/a/6548203/2789764

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve exception handling exception expert rare}

Q62. What is serialVersionUID ?

Core Java

Ans. Everytime an object is serialized the java serialization mechanism automatically computes a hash value by passing the meta information for the class. This id is used during deserialization to verify that the sender and receiver of a serialized object have loaded classes for that object that are compatible with respect to serialization

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve serialVersionUID serialization Asked in 3 Companies expert rare}

Q63. How is hashcode calculated in java ?

or

What are the rules for hashcode calculation ?

Core Java

Ans. General contract of hashCode is:

1.Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer,

2.If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.

3.It is not required that if two objects are unequal according to the equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve hashcode Asked in 1 Companies expert}

Q64. Can constructor be synchronized in Java ?

Core Java

Ans. No, constructors can not be synchronized in Java. In fact using the keyword synchronized with a constructor results in compilation error.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies expert}

Q65. Which memory segment holds String Pool in Java ?

Core Java

Ans. String Pool resides in runtime constant Pool which is a part of Heap memory segment.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve string pool memory management Expert rare}

Q66. Why Java doesn't provide a default constructor if we define an argument constructor ?

Core Java

Ans. Java provides a default constructor ( no argument ) if no constructor is provided by the programmer. Java makes a check during pre compilation if there is any constructor provided by the programmer. If any constructor is provided, Java understands that programmer has provided all the mechanism for initialization and construction of the object and may not even intend to create objects by calling a no argument constructor. For example - One may like to have objects created with self defined state otherwise restrict its creation.

We make the constructor private if we want to make a class singleton as we would like to restrict creation of new objects using new operator and default constructor. Similar could be the situation wherein we would like to construct objects in a particular manner only.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve default constructor expert}

Q67. In Java, would you like to see an explicit destructor?

Core Java

Ans. Yes , a gc method to explicitly call garbage collection immediately on the object. It will provide better flexibility over application that require optimal usage of memory.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve destructor garbage collection Asked in 1 Companies expert}

Q68. What are the advantage of Abstract classes over interfaces with respect to Java 7 ? and What changed in Java 8 to help facilitate that in Java 8 ?

Core Java

Ans. Abstract Classes provide default implementations of methods that are inherited by the classes that extend them, which was not the case for Interfaces. This changed in Java 8, where default implementations are provided for methods.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve abstract classes interfaces default method Asked in 1 Companies expert}

Q69. Why can we have a static inner class but not a static Top level class in Java ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve static class inner classes nested classes Expert rare}

Q70. How ConcurrentHashMap provides better performance compared to HashTable ?

Core Java

Ans. ConcurrentHashMap uses multiple buckets to store Data and hence avoid read locks which facilitates better performance.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve ashTabl expert rare}

Q71. What are the ways to break singleton pattern ?

Design

Ans. If we don't have double checked locking, it can be broken easily through multi threaded access.

Through Reflection.

If multiple class loaders are loading the class.

If the class is serializable or cloneable.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve singleton Asked in 2 Companies expert}

Q72. What is the Big O notation for Fibonacci series - both iterative as well as recursive ?

Algorithm

^{This question was recently asked at 'Canopy Tax'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Big o Notation Asked in 1 Companies expert}

Q73. Write a method that takes a string as input and identifies if any permutation of the String is Palindrome ? For example - ttoobb has a permutation 'bottob' which is a palindrome.

Design

^{This question was recently asked at 'Canopy Tax'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies expert}

Q74. Design database schema for Facebook like application.

Database

^{This question was recently asked at 'Symantec'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve database design Asked in 1 Companies expert}

Q75. How would you design a Thread Pool ?

Design

Ans. By using Executor Framework , we can create Thread pool

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Thread Pool Asked in 1 Companies expert}

Q76. Are final methods faster than regular instance methods ?

Core Java

Ans. Yes. As they cannot be overridden , there is no use of virtual table concept which is used for dynamic binding resolution.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve final methods final keyword expert}

Q77. How is the virtual method table implemented in Java?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve virtual method table method overriding runtime polymorphism object oriented programming (oops) oops concepts expert rare}

Q78. Why Concurrent Collection Classes are fail-fast in Java ?

Core Java

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve concurrent collection classes fail fast fail-fast collections collection classes expert}

Q79. What is something faulty about java ?

Core Java

Ans. Not purely object oriented Language.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve expert}

Q80. How does Garbage Collector work? What are the realizations of Garbage Collector.

Core Java

^{This question was recently asked at 'ExpertSoft'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q81. What is the O notation for the ArrayList and List? And which one would you choose to insert item in the middle?

Data Structure

^{This question was recently asked at 'ExpertSoft'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q82. Do threads have a distinct heap ?

Memory Management

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve memory management heap memory expert}

Q83. Can we do a thread specific heap allocation ?

Memory Management

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve memory management heap memory heap allocation expert}

Search Interview Questions

Help us and Others Improve. Please let us know the questions asked in any of your previous interview.