Monday, January 14, 2008

Java Interview Questions

· What is JVM (Java Virtual Machine)?
· What is JIT (Just- in-Time) Compilation?
· What is Object Oriented Programming?
· What’s a Class?
· What’s an Object?
· What’s the relation between Classes and Objects?
· What are different properties provided by Object-oriented systems?
· How do you implement inheritance in Java?
· How can we implement polymorphism in Java?
· What is an Abstract class?
· What are Abstract methods?
· What’s the difference between “Abstract” classes and “Interfaces”?
· What’s difference between Static and Non-Static fields of a class?
· What are inner classes and what’s the practical implementation of inner classes?
· What are packages?
· What is a constructor in class?
· Can constructors be parameterized?
· What is the use if “instance of” keyword?
· What are Native methods in Java?
· How do refer to a current instance of object?
· Explain in depth Garbage collector?
· How does the garbage collector determine that the object has to be marked for
· Can you explain “finalize ()” method?
· How can we force the garbage collector to run?
· What’s the main difference between “Switch” and “If” comparison?
· What’s the use of JAVAP tool?
· What are applets?
· In which package is, the applet class located?
· What are native interfaces in Java?
· What are Class loaders?
· What is Bootstrap, Extension and System Class loader?
· Can you explain the flow between bootstrap, extension and system class loader?
· Can you explain how can you practically do dynamic loading?
· What is Reflection API in Java?
· What’s the difference between static and dynamic class loading?
· How can you copy one array in to a different array?
· Can you explain the core collection interfaces?
· Can you explain in brief the collection classes which implement the collection
· What’s the difference between standard JAVA array and Array List class?
· What’s the use of “ensure Capacity” in Array List class?
· How can we obtain an array from an Array List class?
· What is “Linked List” class for?
· Can you explain Hash Set class in collections?
· What is Linked Hash Set class?
· What is a Tree Set class?
· What’s the use of Comparator Interface?
· How can we access elements of a collection?
· What is Map and SortedMap Interface?
· Have you used any collection algorithm?
· Why do we use collections when we had traditional ways for collection?
· Can you name the legacy classes and interface for collections?
· What is Enumeration Interface?
· What’s the main difference between Array List / Hash Map and Vector / Hash
· Are String object Immutable, Can you explain the concept?
· What is a String Buffer class and how does it differs from String class?
· What is the difference between String Builder and String Buffer class?
· What is Pass by Value and Pass by reference? How does JAVA handle the same?
· What are access modifiers?
· What is Assertion?
· Can you explain the fundamentals of deep and shallow Cloning?
· How do we implement shallow cloning?
· How do we implement deep cloning?
· What’s the impact of private constructor?
· What are the situations you will need a constructor to be private?
· Can you explain final modifier?
· What are static Initializes?
· If we have multiple static initialize blocks how are the sequence handled?
· Define casting? What are the different types of Casting?
· Can you explain Widening conversion and Narrowing conversion?
· Can we assign parent object to child objects?
· Define exceptions?
· Can you explain in short how JAVA exception handling works?
· Can you explain different exception types?
· Can you explain checked and unchecked exceptions?
· Can we create our own exception class?
· What are chained exceptions?
· What is serialization?
· How do we implement serialization actually?
· What’s the use of Externalizable Interface?
· What is JAVA doc utility?
2: Threading
· What’s difference between thread and process?
· What is thread safety and synchronization?
· What is semaphore?
· What are monitors?
· What’s the importance of synchronized blocks?
· How do we create threads?
· What’s the difference in using run able and extends in threads?
· Can you explain Thread. Sleep?
· How to stop a thread?
· What is wait () and notify ()?
· Can you explain how Scheduling and Priority works in threads?
· Can you explain Yielding in threading?
· What are daemon threads?
· How do we implement single threaded model in servlets?
· How does JAVA interact with databases?
· Can we interact with non-relational sources using JDBC?
· Can you explain in depth the different sections in JDBC?
· Can you explain in short how you go about using JDBC API in code?
· How do you handle SQL exceptions?
Twist: - (A) Can you explain “SQL Exception” class in detail?
Twist: - (A) what is SQL State in SQL Exceptions?
· If there is more than one exception in SQL Exception” class how to go about
displaying it?
· Explain Type1, Type2, Type3, and Type4 drivers in JDBC?
· What are the advantages and disadvantages of using JDBC-ODBC bridge driver?
· What are the advantages and disadvantages of using Native-API/ Partially Java
· What are the advantages and disadvantages of using Net-Protocol/ All-Java
· What are the advantages and disadvantages of using Native-protocol/ All-Java
· Advantages of using JDBC-ODBC bridge driver:-
· Disadvantages of using JDBC-ODBC bridge driver:-
· Advantages of using Native-API/ Partially Java Driver:-
· Dis-advantages of using Native-API/ Partially Java Driver:-
· Advantages of using Net-Protocol/ All-Java driver:-
· Disadvantages of using Net-Protocol/ All- Java driver:-
· Advantages of using Native-protocol/ All-Java driver:-
· Disadvantages of using Native-protocol/ All-Java driver:-
· Define meta-data?
· What is Database Metadata?
· Can you explain “Connection Factory” class?
· I want to display tables of a database how do I do it?
· Define “Result Set Meta Data”?
· What is the difference between “Result Set” and “Row Set”?
· Can “Result Set” objects be serialized?
· Explain “Result Set”, “Row Set”, “Cached Row set”, “JdbcRowset” and “Web
Row Set”?
· What are the different types of result set?
· Explain the concept of “Prepared Statement “statement interface?
· What’s the difference between “Statement” and “Prepared Statement”?
· How can we call stored procedure using JDBC?
· Can you explain “Callable Statement” interface in detail?
· How do you get a result set object from stored procedure?
· (A) How can we do batch updates using “Callable Statement” Interface?
· Define transactions?
· What is ACID in transaction?
· What are the four essential properties of a transaction?
· Explain concurrency and locking?
· What are different types of locks?
· What are the different types of levels of resource on which locks can be placed?
· Define lock escalation?
· What is Table level and Row level locking?
· What are the problems that can occur if you do not implement locking properly?
· What are different transaction levels?
· Twist: - what are different types of locks?
· What is difference between optimistic and pessimistic locking?
· What are deadlocks?
· How can we set transaction level through JDBC API?
· Can you explain transaction control in JDBC?
· What are Save points in a transaction?
4: Servlets and JSP
· What are Servlets?
· What are advantages of servlets over CGI?
· Can you explain Servlet life cycle?
· What are the two important API’s in for Servlets?
· Can you explain in detail “javax.servlet” package?
· What’s the use of Servlet Context?
· How do we define an application level scope for servlet?
· What's the difference between Generic Servlet and Http Servlet?
· Can you explain in detail javax.servlet.http package?
· What’s the architecture of a Servlet package?
· Why is HTTP protocol called as a stateless protocol?
· What are the different ways we can maintain state between requests?
· What is URL rewriting?
· What are cookies?
· What are sessions in Servlets?
· What the difference is between get Session (true) and get Session (false)?
· What’s the difference between “do Post” and “do get” methods?
· Which are the different ways you can communicate between servlets?
· What is functionality of “Request Dispatcher” object?
· How do we share data using “get Servlet Context ()”?
· Explain the concept of SSI?
· What are filters in JAVA?
· Can you explain in short how do you go about implementing filters using Apache
· Twist: - Explain step by step of how to implement filters?
· What’s the difference between Authentication and authorization?
· Explain in brief the directory structure of a web application?
· Can you explain JSP page life cycle?
· What is EL?
· How does EL search for an attribute?
· What are the implicit EL objects in JSP?
· How can we disable EL?
· What is JSTL?
· Can you explain in short what the different types of JSTL tags are?
· (I) How can we use beans in JSP?
· What is the use of ?
· What is tag for?
· What are JSP directives?
· What are Page directives?
· What are including directives?
· Can you explain taglib directives?
· How does JSP engines instantiate tag handler classes’ instances?
· What’s the difference between JavaBeans and taglib directives?
· What are the different scopes an object can have in a JSP page?
· What are different implicit objects of JSP?
· What are different Authentication Options available in servlets?
· Can you explain how do we practically implement security on a resource?
· How do we practically implement form based authentication?
· How do we authenticate using JDBC?
· Can you explain JDBCRealm?
· Can you explain how do you configure JNDIRealm?
· How did you implement caching in JSP?
· What is the difference between Servletcontext and ServletConfig?
· How do we prevent browser from caching output of my JSP pages?
· Can we explicitly destroy a servlet object?
5: EJB
· What is EJB?
· What are the different kind of Ebb’s?
· You are designing architecture for a project how do you decide whether you
should use session, entity or message driven bean?
· Can you explain “EJBHome” and “EJBObject” in EJB?
· Can client directly create object of session or entity beans?
· Can you explain the concept of local interfaces?
· What are the limitations of using Local object?
· Which application server have you used for EJB?
· Can you explain step by step practically developing and deploying EJB
· What is Passivation and Activation in EJB?
· Can beans who are involved in transaction have “Passivation” process?
· How does the server decide which beans to passivity and activate?
· In what format is the conversational data written to the disk?
· Can you explain in brief Life cycle for Stateless and Stateful beans?
6: Struts
· (I)What’s MVC pattern?
· (B) Define struts?
· (A) Can you explain the directory structure for a struts folder in brief?
· (I) Can you give an overview of how a struts application flows?
· Twist: - What are action and action form classes in Struts?
7: XML and Web Services
· What is XML?
· What is the version information in XML?
· What is ROOT element in XML?
· If XML does not have closing tag will it work?
· Is XML case sensitive?
· What is the difference between XML and HTML?
· Is XML meant to replace HTML?
· Can you explain why your project needed XML?
· What is DTD (Document Type definition)?
· What is well formed XML?
· What is a valid XML?
· What is CDATA section in XML?
· What is CSS?
· What is XSL?
· What is element and attributes in XML?
· What are the standard ways of parsing XML document?
· In What scenarios will you use a DOM parser and SAX parser?
· What is XSLT?
· Define XPATH?
· What is the concept of XPOINTER?
· What is a Web Service?
· What is DISCO?
· What is SOAP?
· What is WSDL?
· Can you explain UDDI?
· Can you explain JAXP?
· What is a XML registry?
· What is JAXR?
· What is JAXM?
· Can you explain JAX-RPC?
· How do you practically implement Web Services?
· How do we consume a web service?
· Are web services Stateful?
8: Internationalization
· Can you explain i18n and l10n?
· Can you explain internationalization and localization?
· What is Locale?
· How do we display numbers, currency and Dates according to proper Locale
· what are resource bundles?
· How do we load a resource bundle file?
· How can we do inheritance in resource bundles?
9: JNI
· What is Native Interface in JAVA?
· Can you say in brief steps required to implement Native interfaces in Java?
· Can JNI be used for VB6, C# or VB.NET directly?
· What are JNI functions and pointers?
· How does the garbage collector know JNI objects are no more used?
· Twist: - What are the different types of references JNI supports?
· Twist: - How to do you delete global objects?
· How does the native language C or C++ understand data types in JAVA?
· Can you explain exception handling in JNI?
· What are limitations for “JNIEnv” pointer in multi- threading scenarios?
· What are the advantages and disadvantages of using “JNI”?
10: Architecture
· What are design patterns?
· Can you list down all patterns and their classification?
· What is the difference between Factory and Abstract Factory Patterns?
· What is MVC pattern?
· How can we implement singleton pattern in JAVA?
· How do you implement prototype pattern in JAVA?
· Can you give a practical implementation of FAÇADE patterns?
· How can we implement observer pattern in JAVA?
· What is three tier architecture?
· What is Service Oriented architecture?
· What is aspect oriented programming?
· How can you implement AOP practically in JAVA?
· What is Inversion of control?
· What is OR mapping?
11: UML
· What is UML?
· How many types of diagrams are there in UML?
· What are advantages of using UML?
· What is the sequence of UML diagrams in project?
· Give a small brief explanation of all Elements in activity diagrams?
· Explain Different elements of a collaboration diagram?
· Explain Component diagrams?
· Describe the various components in sequence diagrams?
· What are the elements in State Chart diagrams?
· Describe different elements in Static Chart diagrams?
· Explain the different elements of a Use Case?
12: Project Management
· What is project management?
· Is spending in IT projects constant through out the project?
· Who is a stakeholder?
· Can you explain project life cycle?
· Are risk constant through out the project?
· Can you explain different software development life cycles?
· What is triple constraint triangle in project management?
· What is a project baseline?
· What is effort variance?
· How is normally a project management plan document organized?
· (I)How do you estimate a project?
· What is CAR (Causal Analysis and Resolution)?
· What is DAR (Decision Analysis and Resolution)?
· What is a fish bone diagram?
· What is pare to principle?
· How do you handle change request?
· What is internal change request?
· What is difference between SITP and UTP in testing?
· What is the software you have used for project management?
· What are the metrics followed in project management?
· You have people in your team who do not meet there deadlines or do not perform
what are the actions you will take?
· What is black box testing and White box testing?
· What’s the difference between Unit testing, Assembly testing and Regression
· What is V model in testing?
· How do you start a project?
· How did you do resource allocations?
· How will you do code reviews?
· What is CMMI?
· What are the five levels in CMMI?
· What is continuous and staged representation?
· Can you explain the process areas?
· What is SIX sigma?
· What is DMAIC and DMADV?
· What are the various roles in Six Sigma implementation?
· What are function points?
· What are the different types of elementary process in FPA?
· What are the different elements in Functions points?
· Can you explain in GSC and VAF in function points?
· What are unadjusted function points and how is it calculated?
· Can you explain steps in function points?
· What is the FP per day in your current company?
· Do you know Use Case points?
· What is SMC approach of estimation?
· How do you estimate maintenance project and change requests?
13: Database
· What is database or database management systems (DBMS)?
· What is SQL?
· What’s difference between DBMS and RDBMS?
· What are CODD rules?
· What are E-R diagrams?
· How many types of relationship exist in database designing? What is
normalization? What are different type of normalization?
· What is denormalization?
· Can you explain Fourth Normal Form?
· Can you explain Fifth Normal Form?
· What’s the difference between Fourth and Fifth normal form?
· Have you heard about sixth normal form?
· What are DML and DDL statements?
· How do we select distinct values from a table?
· What is like operator for and what are wild cards?
· Can you explain Insert, Update and Delete query?
· What is order by clause?
· What is the SQL In clause?
· Can you explain the between clause?
· I have an employee salary table how do we find the second highest from it?
· What are different types of joins in SQL?
· What is “CROSS JOIN”?
· You want to select the first record in a given set of rows?
· What is the default “SORT” order for a SQL?
· What is a self-join?
· What’s the difference between DELETE and TRUNCATE?
· .What are Wildcard operators?
· Twist: - What is like clause in SQL?
· What’s the difference between “UNION” and “UNION ALL”?
· What are cursors and what are the situations you will use them?
· What are the steps to create a cursor?
· What is “Group by” clause?
· What is the difference between “HAVING” and “WHERE” clause?
· What is a Sub-Query?
· What are Aggregate and Scalar Functions?
· Can you explain the SELECT INTO Statement?
· What is a View?
· What is “Correlated Sub queries”?
· What is SQl injection?
· What is “Data Warehousing”?
· What are Data Marts?
· What are Fact tables and Dimension Tables?
· Twist: - What is Dimensional Modeling?
· Twist: - What is Star Schema Design?
· What is Snow Flake Schema design in database?
· Twist: - What’s the difference between Star and Snow flake schema?
· What is ETL process in Data warehousing?
· Twist: - What are the different stages in “Data warehousing”?
· What is “Data mining”?
· Compare “Data mining” and “Data Warehousing”?
· What are indexes?
· What are B-Trees?
· I have a table which has lot of inserts, is it a good database design to create
indexes on that table?
· Twist: - Insert’s are slower on tables which have indexes, justify it?
· Twist: - Why do page splitting happen?
· What are “Table Scan’s” and “Index Scan’s”?
· What are the two types of indexes and explain them in detail?
· Twist: - What’s the difference between clustered and non-clustered indexes?

No comments: