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

Interview Questions and Answers - Order By Rating

Q1501. Does Declaring an object "final" makes it immutable ?

Ans. Only declaring variables as final makes them immutable. Making objects final means that the object handler cannot be used to target some other object but the object is still mutable.

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

_{Like Discuss Correct / Improve java oops final immutable immutability immutable immutability object}

Q1502. Can we access instance variables within static methods ?

Core Java

Ans. Yes.we cannot access them directly but we can access them using object reference.Static methods belong to a class and not objects whereas non static members are tied to an instance. Accessing instance variables without the instance handler would mean an ambiguity regarding which instance the method is referring to and hence its prohibited.

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

_{Like Discuss Correct / Improve java oops static static methods java keywords Asked in 1 Companies}

Q1503. Give an Example of checked and unchecked exception ?

Core Java

Ans. ClassNotFoundException is checked exception whereas NoClassDefFoundError is a unchecked exception.

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

_{Like Discuss Correct / Improve java exceptions checked exceptions unchecked exceptions exception handling Asked in 2 Companies}

Q1504. How can we make sure that a code segment gets executed even in case of uncatched exceptions ?

Ans. By putting it within finally.

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

_{Like Discuss Correct / Improve java oops exceptions finally uncatched exceptions basic frequent}

Q1505. What is "super" used for ?

Ans. Used to access members of the base class.

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

_{Like Discuss Correct / Improve java oops java keywords super basic interview question Asked in 2 Companies basic frequent}

Q1506. Difference between boolean and Boolean ?

Core Java

Ans. boolean is a primitive type whereas Boolean is a class.

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

_{Like Discuss Correct / Improve java oops wrapper classes boolean vs Boolean basic rare}

Q1507. What is a finalize method ?

Core Java

Ans. finalize() method is called just before an object is destroyed.

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

_{Like Discuss Correct / Improve java oops finalize garbage collection basic interview question Asked in 1 Companies basic frequent}

Try 1 Question(s) Test

Very frequently asked in phone and walk in interviews.

Q1508. What are Marker Interfaces ? Name few Java marker interfaces ?

Core Java

Ans. An interface without any method declaration is called as marker interface. there are 3 in-built interfaces in JVM i.e. serializable, clonable, remote

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

_{Like Discuss Correct / Improve java oops interfaces marker interface serializable clonable Asked in 21 Companies intermediate frequent}

Try 1 Question(s) Test

Q1509. Is runnable a Marker interface ?

Core Java

Ans. No , it has run method declared.

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

_{Like Discuss Correct / Improve java oops interfaces marker interface runnable yes-no}

Frequently asked to fresh graduates.

Q1510. Difference between Process and Thread ?

Operating System

Ans. Process is a program in execution whereas thread is a separate path of execution in a program.

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

_{Like Discuss Correct / Improve java threads multi threading operating system process vs thread Asked in 24 Companies basic frequent}

Frequently asked to fresh graduates.

Q1511. What is a Deadlock ?

Operating System

Ans. When two threads are waiting each other and cant precede the program is said to be deadlock.

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

_{Like Discuss Correct / Improve java threads multi threading operating system deadlock concurrency Asked in 23 Companies basic frequent}

Q1512. Difference between Serialization and Deserialization ?

Core Java

Ans. Serialization is the process of writing the state of an object to a byte stream. Deserialization is the process of restoring these objects.

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

_{Like Discuss Correct / Improve java oops serialization deserialization serialization vs deserialization Asked in 2 Companies basic frequent}

Try 1 Question(s) Test

Q1513. Explain Autoboxing ?

Core Java

Ans. Autoboxing is the automatic conversion that the Java compiler makes between the primitive types and their corresponding object wrapper classes

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

_{Like Discuss Correct / Improve java java5 autoboxing wrapper classes Asked in 2 Companies basic frequent}

Q1514. What are Wrapper Classes ? What are Primitive Wrapper Classes ?

Core Java

Ans. A wrapper class is any class which "wraps" or "encapsulates" the functionality of another class or component. A Wrapper Class that wraps or encapsulates the primitive data type is called Primitive Wrapper Class.

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

_{Like Discuss Correct / Improve java wrapper classes primitive wrapper classes}

Q1515. What Design pattern Wrapper Classes implement ?

Design

Ans. Adapter.

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

_{Like Discuss Correct / Improve java wrapper classes adapter design pattern design pattern}

Q1516. Different types of memory used by JVM ?

Core Java

Ans. Class , Heap , Stack , Register , Native Method Stack.

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

_{Like Discuss Correct / Improve java jvm memory management memory advanced architecture technical architect Asked in 1 Companies intermediate frequent}

Try 5 Question(s) Test

Q1517. What is a class loader ? What are the different class loaders used by JVM ?

Core Java

Ans. Part of JVM which is used to load classes and interfaces.

Bootstrap , Extension and System are the class loaders used by JVM.

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

_{Like Discuss Correct / Improve java class loaders classloaders jvm java memory management advanced Asked in 3 Companies}

Q1518. What is a Static import ?

Core Java

Ans. By static import , we can access the static members of a class directly without prefixing it with the class name.

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

_{Like Discuss Correct / Improve java java5 static import static java keyword static import Asked in 4 Companies basic frequent}

Very frequently asked. Usually difference between String,StringBuffer and StringBuilder is asked in different variations.

Q1519. Difference between StringBuffer and StringBuilder ?

Core Java

Ans. StringBuffer is synchronized whereas StringBuilder is not.

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

_{Like Discuss Correct / Improve java string stringbuffer string class stringbuilder synchronized basic interview question infosys technologies Asked in 17 Companies basic frequent}

Try 1 Question(s) Test

Q1520. Difference between Map and HashMap ?

Core Java

Ans. Map is an interface where HashMap is the concrete class.

Sample Code for map

Sample Code for hashmap

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

_{Like Discuss Correct / Improve java collections hashmap map basic frequent}

Q1521. What is a Property class ?

Core Java

Ans. The properties class is a subclass of Hashtable that can be read from or written to a stream.

Sample Code for Load Properties using Property Class

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

_{Like Discuss Correct / Improve java collections hashtable map synchronization synchronized}

Very frequently asked in different variations. Frequently asked in Deloitte ( 2 feedback ) , HCL Tech ( 3 feedback ), TCS and Coginizant (CTS)

Q1522. Explain the scenerios to choose between String , StringBuilder and StringBuffer ?

or

What is the difference between String , StringBuilder and StringBuffer ?

Core Java

Ans. If the Object value will not change, use String Class because a String object is immutable.

If the Object value can change and will only be modified from a single thread, use StringBuilder because StringBuilder is unsynchronized(means faster).

If the Object value may change, and can be modified by multiple threads, use a StringBuffer because StringBuffer is thread safe(synchronized).

Sample Code for String

Sample Code for StringBuffer

Sample Code for StringBuilder

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

_{Like Discuss Correct / Improve java string class string stringbuilder stringbuffer String vs StringBuffer String vs StringBuilder String vs StringBuilder vs StringBuffer StringBuffer vs stringBuilder Asked in 29 Companies basic frequent}

Try 3 Question(s) Test

Q1523. Can we have multiple servlets in a web application and How can we do that ?

Java EE

Ans. Yes by making entries in web.xml

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

_{Like Discuss Correct / Improve j2ee servlets servelets web application java web.xml yes-no architecture}

Q1524. How can we manage Error Messages in the web application ?

Solution

Ans. Within message.properties file.

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

_{Like Discuss Correct / Improve j2ee web application struts spring Asked in 1 Companies}

Frequently asked to fresh graduates.

Q1525. Is JVM, a compiler or interpretor ?

Ans. Its an interpretor.

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

_{Like Discuss Correct / Improve java jvm compiler interpretor basic frequent}

Q1526. Difference between loadClass and Class.forName ?

Ans. loadClass only loads the class but doesn't initialize the object whereas Class.forName initialize the object after loading it.

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

_{Like Discuss Correct / Improve java class loaders jvm advanced}

Q1527. Should we override finalize method ?

Ans. Finalize is used by Java for Garbage collection. It should not be done as we should leave the Garbage Collection to Java itself.

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

_{Like Discuss Correct / Improve java garbage collection java memory management finalize}

Try 2 Question(s) Test

Q1528. Difference between Factory and Builder Design Pattern ?

Design

Ans. Builder pattern is the extension of Factory pattern wherein the Builder class builds a complex object in multiple steps.

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

_{Like Discuss Correct / Improve java design pattern factory design pattern builder design pattern Asked in 1 Companies expert}

Q1529. Difference between Builder and Composite ?

Ans. Builder is a creational Design Pattern whereas Composite is a structural design pattern. Composite creates Parent - Child relations between your objects while Builder is used to create group of objects of predefined types.

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

_{Like Discuss Correct / Improve java design pattern builder composite creational design pattern structural design pattern}

Q1530. Example of Chain of Responsibility Design Pattern ?

Ans. Exception Handling Throw mechanism.

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

_{Like Discuss Correct / Improve java design pattern chain of responsibility expert}

Search Interview Questions

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