Java Developer Interview questions

By Sandeep Desai (http://www.thedesai.net)

General questions

• Largest codebase ever worked on
• Describe favorite project
• Development Websites and blogs visited
• Communication skills
• Confidence

General Developer Knowledge

• Regular Expressions
• Patterns knowledge (Singleton, Factory, Proxy)
• UML knowledge
• Test Driven Development
• Unix Utilities Knowledge such as grep, perl, xargs
• Code structure
• When you are stuck with a problem you don’t understand, what process do you use to solve it

Java Knowledge

• Java Books read
• Java websites
• Sun Certified Java Programmer ?
• Java IDE
• Swing knowledge
• Servlet/JSP
• EJB
• JDBC
• XML
• JUnit knowledge

RDBMS knowledge

• SQL knowledge
• Employee Table empno, empname
• Department table deptno, deptname
• left join ?

Data Structures

· Name data structures and algorithms that you know about

Describe development project

Java questions

· Difference between JDK and JRE

· Whats new in JDK 1.5

o Generics, Autoboxing, for loop, Annotations, Concurrent API

· Describe difference between interface and abstract class

o interfaces provide multiple inheritance

· How to instantiate abstract class or interface

· Write an abstract class

· Write an interface

· Are interfaces useful outside of multiple inheritance

· What are exceptions

· What is the collection API

· What is reflection

· What is garbage collection

· How can you force garbage collection

· What is OOP

· What access specifiers available in Java

· What data types are available in Java

· How do you store int in an ArrayList

· What is final

· Does Java have goto

· What are inner classes? Anonymous inner classes

JDBC

Servlet/JSP

Hibernate

• What are POJO
• What is Entity and Value Object
• What is Pessimistic and Optimistic Locking
• How do you implement equals
• What is lazy and eager fetching
• What is difference between Query and Criteria
• What is LazyInitializationException

EJB

• What types of Beans does EJB have (Session, Entity, Message)
• What is Entity Bean
• What is CMP

Spring

• What IoC/Dependancy Injection
• Describe Spring Config XML file
• What kind of exception does Spring recommend
• What is AOP
• Cross cutting concerns, Pointcuts, Mixin, Weaving
• How does Hibernate and Spring integrate

HTML/CSS/Javascript

• What is relationship between HTML and CSS
• What kind of language is Javascript
• What kind of coding did you do in Javascript
• How does Javascript handle inheritance
• What is AJAX
• What data format can you use for AJAX
• What is DHTML

Other Interpreted Languages

• Perl