100 Interview Questions

100 Java Technical Questions to Software Companies


1.what is polymorphism with example ? types of polymorphism?

2.what is final method & final variable with example?

3.How to deploy your struts application in JBOSS?

4.what exactly happens when we execute "Class.forname("Driver class name");"?Explain in detail

5.What are 5 common problems in the software development process?

6.What are the design patterns and How can they make life easier for software development ?

7.Design the Factory pattern and What is its application ?

8.What is impedance mismatch and How to solve the problem?

9.How can we design/implement singleton object

10.what is mean by overriding in which situation we will use?

11.How to create an instance of a class without using "new" operator?

12.How can we serialize a jsp page.

13.What are the benefits obtained by using the Client Server oriented TP Monitors Client Server applications?

14.What are the three types of SQL database server architecture?

15.what is servlet engineer?

16.what is the difference b/w design pattern and architecture?

17.In the HashMap, we know the values but we dont know the key, then how can we get the key from HashMap ?

18.What is the use of a form in html page? Is there any way to submit the page without using the form.

19.what is the difference between abstract class and Interface?where we can use it in realtime projects?

20.which class to use when concatenating strings in a loop.

21.explain System.out.println?

22.what is the difference between equals method and ==?

23.Iterator in the HashMap is fail-safe means ?

24.how to deploy apache tomcat server to weblogic server in java?

25.what is difference between method overloading & method overridding with example?

26.what is difference between perfom() & excute() ?

27.write a progam hashmap & hashtable?

28.Can java provide security ?

29.How to implement or use the singleton class in java?

30.What is the singleton class in java?

31.What is JIT ?

32.Is it possible to create Userdefined Unchecked Exception also? If Yes, give an example?

33.What is the need of "creating and throwing an UserdefinedException" when the "Exception" class is already available?

34.What is the difference between throw and throws? What is the similarity between try and throw?

35.Why operator overloading is not in Java?

36.Is Struts Action class Thread Safe?

37.what is webservices?

38.why java does not support multiple inheritance?

39.we cant Override Jsp Service method?Why?

40.What is the difference between sendRedirect() and forward()?

41.what s the difference b/w EJB 2.0 and EJB 3.0 technically?

42.what is ForwardAction and IncludeAction in struts?
43.Different types of threads?

44.what is features of jdk 1.5?

45.what is java bean?where can we use it?

46.what is jndi?

47.Diff between C++ and java?

48.what is an anonymous class?

49.what is the difference between pagecontext and servletcontext?

50.What is data abstraction? Elaborate with example?

51.Is ResultSet class?

52.whats the diff between jsp and servlets?

53.Differences between UNIQUE and DISTINCT in select statements?

54.Which is not Object in Java?

55.which method is used to know the status of the Thread?

56.what is data access layer?

57.Which Design Patterns you know?

58.what is MVC Pattern?

59.What is the difference between C++ & Java?

60.how session will be expired?

61.what is overloading in java?

62.What is serializable interface?

63.What is CardLayout?

64.How can we create object to a class in a jsp file?

65.which situation you use static include and dynamic include in jsp?

66.Difference between overloading and Overriding.

67.What is the exact difference in between Unicast and Multicast object ?

68.Which Math method is used to calculate the absolute value of a number?

69.What is meant by throwing an Exception?
.Write a program to know whether string is palindrome or not?

70 A C program is given and asked what will be output.............

71.A Recursive function is given asked what will be output how and why?

72.write a prg / function to remove the duplicate from a sorted array. (8 m)

5.write a prg to genrate fibonacci series upto 100 recursively. (7 m)

73.predict the output of the following:
char c[]={ " enter" , "first" , "print" , "new" }.;
char **cp[]={c+3, c+2, c+1, c};
char ***cpp[]=cp;
printf("%s", ++*cp);
printf("%s",--*++cp);

74.A program given and asked what are variables value1 and value2 stores?(ie, in that program they store GCD and LCM)

75.Write a program to sort linked list.

In a table their 20 records.I had update 6 records???How can see and retrieve particular 6 records


76.class A { class B { psvm(String args[]) { } } } if the prg saved in A.java whats the o/p?
78.the control commands in the report program are
atfirst,atnew,atlast,atend of and what is the difference
between them
79.Difference between abstract class and interface
80.what's diff between struts 1.1 & 1.2?
81.can we have virtual functions in java?
82.what is Assertion?
83.Can we declare an anonymous class as both extending a class and implementing an interface?
84.What is hard code & soft code?
85.what is the difference between ArrayList and Vector?
86.How do you set security in applets?
87.what is an object and how do you allocate memory to it?
88.what is meant by string pooling?
89.Why Java is not purely object oriented?
90.What are other modifiers?
91.Can try statements be nested?
92.Can an exception be rethrown?
93.Name the class that used to read objects directly from a stream?
94.What Method and class used for Connection pooling ?
95.What are integer overflows and underflows and how to handle them?
96.How to eliminate duplicates from an array?
97.For which statements we use a label?
98.What is 3-tier model?
99.Difference between Application and Applet ?
100.Is there is any error if you have multiple main methods in the same class?