Apr 25, 2013

Hibernate OnetoMany mapping with composite key

Consider following scenario where we need to map one entity with other where one column of composite primary key of child table is by which we are mapping it with parent entity

Table 1: Employee_Details
Emp_Id (pk/id)
Emp_First_Name

Table 2: Emp_Skill_Level
Emp_Id (pk/id # 1)
Skill_Id (pk/id # 2)
Skill_Level

Now here we have a situation where in one table/entity we will have one column and Primary Key (or this will be my id field in mapped entity). The second table/entity has two columns as primary key and in mapped entity both these fields will be used to define id.

But we want to use only one column of Emp_Skill_Level to map with Employee_Details (For now lets assume we do not have any other table which lists details about Skill and all details are present in this second table)




Apr 10, 2013

Java interview questions.

1.    What was your last project?
2.    What was your role in your last project?
3.    What was the architecture of your project?
4.    How data was flowing in your application?
5.    What version of java you were using in your project? What is the latest version of java?
6.    When we say JVM, which command exactly we talk about? Javac, java, javaw?
7.    What are new features in java 5?
8.    What is generics?
9.    What is annotation?
10.    What are new features in java 7?
11.    What will be new features in java 8?
12.    What are the basic concepts of Object Oriented Programming (OOPS)?
13.    What are different ways of creating objects? (new, clone, deserialize)
14.    What is inheritance?
15.    Does java support multiple inheritance?
16.    What is Overloading and Overriding?
17.    What is polymorphism?
18.    What is Abstraction?
19.    What is data encapsulation?
20.    What are different levels of access modifier?
21.    What is different between default and protected access modifier?
22.    What is Exception handling? What are different ways of handling Exceptions?
23.    What is interface and what is marker interface?
24.    Explain Serialization and deserialization.
25.    What is serializable and what is externalizable?
26.    Where you can use Abstract class and where you can use Interface any example?
27.    Can you write GenericInterface intrfc = new ImplClass(); where class ImplClass implements interface GenericInterface?
28.    Can we have constructor in Abstract class? Any use of it?
29.    What do you mean by “String is immutable class”?
30.    What is final, finally and finalize?
31.    What is difference between StringTockenizer, StringBuffer and StringBuilder?
32.    What is Collection API?
33.    What are different classes and interfaces used in Collection API?
34.    What is difference between List and Set?
35.    What is difference between Arraylist and Vector? When to use what?
36.    What is difference between Set and Map?
37.    What is different between HashSet and TreeSet?
38.    What is difference between HashsMap and HashTable?
39.    What is difference between HashMap and TreeMap?
40.    What is Comparable interface and what is Comparator interface?
41.    What is multithreaded environment?
42.    How to create threads?  Which method is preferred and why?
43.    What is notify and notifyall?
44.    What is synchronization?
45.    What is block level and method level synchronization? Which one is preferred?
46.    By synchronization what are you protecting? Methods or data?
47.    Explain different thread states in multithreading.
48.    If there is a static method and you want to synchronize it what will you do?
49.    What if you have four methods and you want to synchronize them in group of two?
50.    What is JDBC?
51.    What do you mean by “Loading JDBC driver”?
52.    What is difference between Statement and Prepared Statement?
53.    Prepared statement is precompiled statement then where it gets compiled? On DB side or Java side?
54.    What is ORM? Do you know any ORM framework?
55.    What are different types of driver?
56.    Where you can find code for java.sql.Connection object?
57.    What are steps in JDBC?
58.    What is connection pooling?
59.    What is callable statement?
60.    What will be sequence of closing JDBC resources?
61.    What is difference between webserver and application server?
62.    What is MVC architecture?
63.    Explain Servlet Life cycle.
64.    What are implicit objects in jsp?
65.    What are different components in web.xml?
66.    What is weblogic.xml/jboss-web.xml?
67.    How you configure security roles in web.xml?
68.    What is design pattern?
69.    Any MVC Framework you are aware of?
70.    What design pattern Struts framework uses?
71.    What is Singleton pattern?
72.    How to handle multithreading in Singleton pattern?
73.    What is Factory Pattern?
74.    What is difference between Factory Pattern and Abstract Factory Pattern?
75.    What is EJB?
76.    What are different types of EJB?
77.    What is MDB?
78.    What is JMS?
79.    What are different ways of implementing JMS? What is P2P and PubSub Communication?
80.    Any middleware you are aware of to use JMS?
81.    What are differences between Struts 1 and 2?
82.    What is request life cycle in Struts 1?
83.    What is custom tag in jsp?
84.    Explain validation framework in Struts 1.
85.    What is IoC and what is Dependency Injection?
86.    What are different types of DI we have?
87.    What is AOP?
88.    What is constructor injection and what is getter injection?
89.    What is auto wiring in Spring framework?
90.    What is Hibernate?
91.    What is Dialect in Hibernate?
92.    Why all Exceptions in Hibernate are Runtime (unchecked) Exception and not checked Exception?
93.    What is difference between get and Load methods of Hibernate?
94.    What is named query in Hibernate?
95.    What are differences between Hibernate 3 and 4?
96.    How to perform JDBC operations in Hibernate 4?
97.    Can you write your own Dialect for any DB in Hibernate?
98.    What is web service?
99.    What are different components in Webservices?
100.    When to use Webservice and when to use EJB?