Q1. Which access specifiers can be used with top level class ?
a. public or default
b. public or private
c. public or protected
d. protected or default
show Answer
a. public or default
b. public or private
c. public or protected
d. protected or default
show Answer
Ans. public or default
Q2. Which of the following can be marked static ?
a. Methods , Variables and Initialization Blocks.
b. Methods , Variables , Initialization Blocks and Outer Classes and nested Classes.
c. Methods , Variables , Initialization Blocks and Outer Classes.
d. Methods , Variables , Initialization Blocks and nested Classes
show Answer
a. Methods , Variables and Initialization Blocks.
b. Methods , Variables , Initialization Blocks and Outer Classes and nested Classes.
c. Methods , Variables , Initialization Blocks and Outer Classes.
d. Methods , Variables , Initialization Blocks and nested Classes
show Answer
Ans. Methods , Variables , Initialization Blocks and nested Classes
Q3. Which of the following cannot be marked static ?
a. Constructors , Classes ( Outer ) , Classes ( nested ), Interfaces , Local variables , Inner Class methods and instance variables.
b. Constructors , Classes ( Outer ) , Interfaces , Local variables , Class variables , Class Methods , Inner Class methods and instance variables.
c. Constructors , Classes ( Outer ) , Interfaces , Local variables , Inner Class methods and instance variables.
d. Constructors , Classes ( Outer ) , Classes (Nested), Interfaces , Local variables , Inner Class methods and instance variables
show Answer
a. Constructors , Classes ( Outer ) , Classes ( nested ), Interfaces , Local variables , Inner Class methods and instance variables.
b. Constructors , Classes ( Outer ) , Interfaces , Local variables , Class variables , Class Methods , Inner Class methods and instance variables.
c. Constructors , Classes ( Outer ) , Interfaces , Local variables , Inner Class methods and instance variables.
d. Constructors , Classes ( Outer ) , Classes (Nested), Interfaces , Local variables , Inner Class methods and instance variables
show Answer
Ans. Constructors , Classes ( Outer ) , Interfaces , Local variables , Inner Class methods and instance variables.
Q4. Which is of the following is NOT TRUE for JVM ?
a. JVM reads Byte Code and generates Machine Code.
b. JVM is a virtual Machine that acts as a intermediary between Java Application and Host Operating System.
c. JVM reads Source Code and generates Byte Code.
d. JVM acts as a translator that translates different Machine code ( on the basis of Host Machine ) for a common Byte Code.
show Answer
a. JVM reads Byte Code and generates Machine Code.
b. JVM is a virtual Machine that acts as a intermediary between Java Application and Host Operating System.
c. JVM reads Source Code and generates Byte Code.
d. JVM acts as a translator that translates different Machine code ( on the basis of Host Machine ) for a common Byte Code.
show Answer
Ans. JVM reads Source Code and generates Byte Code.
Q5. Interface can only have ...
a. Member elements and Methods.
b. Static Variables and Static Methods.
c. Static Final Variables and Instance Method Declarations.
d. Member Elements , Instance Methods, Static variables and Static Methods.
show Answer
a. Member elements and Methods.
b. Static Variables and Static Methods.
c. Static Final Variables and Instance Method Declarations.
d. Member Elements , Instance Methods, Static variables and Static Methods.
show Answer
Ans. Static Final Variables and Instance Method Declarations.
Q6. Which of the following collection maintain its elements in Natural Sorted order ?
a. HashMap
b. TreeMap
c. LinkedHashMap
d. LinkedMap
show Answer
a. HashMap
b. TreeMap
c. LinkedHashMap
d. LinkedMap
show Answer
Ans. TreeMap
Q7. Which of the following collections stores its elements in insertion Order ?
a. HashMap
b. TreeMap
c. LinkedHashMap
d. LinkedMap
show Answer
a. HashMap
b. TreeMap
c. LinkedHashMap
d. LinkedMap
show Answer
Ans. LinkedHashMap
Q8. If we add Enum constants to a sorted collection ( Treemap , TreeSet ), What will be the order in which they will be maintained ?
a. Sorted Collection wont maintain them in any order.
b. Insertion Order
c. Order in which constants are declared.
d. Natural Sorting Order.
show Answer
a. Sorted Collection wont maintain them in any order.
b. Insertion Order
c. Order in which constants are declared.
d. Natural Sorting Order.
show Answer
Ans. Order in which constants are declared.
Q9. If we try to add duplicate key to the HashMap, What will happen ?
a. It will throw an exception.
b. It won't add the new Element without any exception.
c. The new element will replace the existing element.
d. Compiler will identify the problem and will throw an error.
show Answer
a. It will throw an exception.
b. It won't add the new Element without any exception.
c. The new element will replace the existing element.
d. Compiler will identify the problem and will throw an error.
show Answer
Ans. The new element will replace the existing element.
Q10. In what order the elements of a HashSet are retrieved ?
a. Random Order
b. Insertion Order
c. Natural Sorting Order
d. Inverse Natural Sorting Order
show Answer
a. Random Order
b. Insertion Order
c. Natural Sorting Order
d. Inverse Natural Sorting Order
show Answer
Ans. Random Order
Q11. Which of the following is not type of inner classes ?
a. Simple Inner Class
b. Static Nested Inner Class
c. Method Nested Static Inner Class
d. Anonymous Inner Class
show Answer
a. Simple Inner Class
b. Static Nested Inner Class
c. Method Nested Static Inner Class
d. Anonymous Inner Class
show Answer
Ans. Method Nested Static Inner Class
Q12. Which of the following was not introduced with Java 5 ?
a. Generics
b. Strings within Switch
c. Enums
d. Annotations
show Answer
a. Generics
b. Strings within Switch
c. Enums
d. Annotations
show Answer
Ans. Strings within Switch
Q13. Which interface does java.util.Hashtable implement ?
a. List
b. Set
c. Collection
d. Map
show Answer
a. List
b. Set
c. Collection
d. Map
show Answer
Ans. Map
Q14. Which of the following is false ?
a. HashMap came before HashTable.
b. HashMap allows null values whereas Hashtable doesn’t allow null values.
c. HashTable and HashMap allow Key-Value pairs.
d. Hashtable is synchronized whereas HashMap is not.
show Answer
a. HashMap came before HashTable.
b. HashMap allows null values whereas Hashtable doesn’t allow null values.
c. HashTable and HashMap allow Key-Value pairs.
d. Hashtable is synchronized whereas HashMap is not.
show Answer
Ans. HashMap came before HashTable.
Q15. Which of the following is true ?
a. We can serialize static variables
b. We can serialize transient variables
c. We can serialize final variables
d. We can serialize instance methods
show Answer
a. We can serialize static variables
b. We can serialize transient variables
c. We can serialize final variables
d. We can serialize instance methods
show Answer
Ans. We can serialize final variables
Q16. Which of the following is not the use of this keyword ?
a. Passing itself to another method
b. To call the static method
c. Referring to the instance variable when local variable has the same name
d. Calling another constructor in constructor chaining
show Answer
a. Passing itself to another method
b. To call the static method
c. Referring to the instance variable when local variable has the same name
d. Calling another constructor in constructor chaining
show Answer
Ans. To call the static method
Q17. Which of the collections allows null as the key ?
a. HashTable
b. HashMap
c. TreeMap
d. LinkedHashMap
show Answer
a. HashTable
b. HashMap
c. TreeMap
d. LinkedHashMap
show Answer
Ans. HashTable
Q18. What is the initial state of a thread when it is created and started ?
a. Wait
b. Running
c. Ready
d. Sleep
show Answer
a. Wait
b. Running
c. Ready
d. Sleep
show Answer
Ans. Ready
Q19. What state does a thread enter when it terminates its processing?
a. Wait
b. Ready
c. Dead
d. Running
show Answer
a. Wait
b. Ready
c. Dead
d. Running
show Answer
Ans. Dead
Q20. How many bits are used to represent Unicode ?
a. 8 bits
b. 16 bits
c. 24 bits
d. 32 bits
show Answer
a. 8 bits
b. 16 bits
c. 24 bits
d. 32 bits
show Answer
Ans. 16 bits
Q21. Overridden methods must have the same ...
a. name
b. name and argument list
c. name, argument list, and return type
d. name, argument list, return type and belong to the same class
show Answer
a. name
b. name and argument list
c. name, argument list, and return type
d. name, argument list, return type and belong to the same class
show Answer
Ans. name and argument list
Q22. Which of the following annotation is used to avoid executing Junits ?
a. @explicit
b. @ignore
c. @avoid
d. @NoTest
show Answer
a. @explicit
b. @ignore
c. @avoid
d. @NoTest
show Answer
Ans. @ignore
Q23. Which of the following is usually not part of EAR file ?
a. Server Configuration files
b. HTML and Media Files
c. Application Configuration files
d. Class files
show Answer
a. Server Configuration files
b. HTML and Media Files
c. Application Configuration files
d. Class files
show Answer
Ans. Server Configuration files
Q24. Which of the following file is called deployment descriptor ?
a. application.xml
b. project.xml
c. web.xml
d. build.xml
show Answer
a. application.xml
b. project.xml
c. web.xml
d. build.xml
show Answer
Ans. web.xml
Q25. How can we execute a Java class independently if it doesn't have a static main method ?
a. By initiating the flow in any of the static method
b. By initiating the flow in any of static block
c. By initiating the flow in any other instance method named as main
d. By initiating the flow in any other instance method named as main and making it final
show Answer
a. By initiating the flow in any of the static method
b. By initiating the flow in any of static block
c. By initiating the flow in any other instance method named as main
d. By initiating the flow in any other instance method named as main and making it final
show Answer
Ans. By initiating the flow in any of static block
Ans. 64 bit
Ans. 64 bit
Ans. 16 bit
Q29. Which keyword is used to provide explicit access of a code block to single thread ?
a. Transient
b. Final
c. Explicit
d. Synchronized
show Answer
a. Transient
b. Final
c. Explicit
d. Synchronized
show Answer
Ans. Synchronized
Q30. Which of the following exception is thrown when we try to access element which is beyond the size ?
a. NullPointerException
b. ArrayIndexOutOfBoundException
c. ArithmeticException
d. ParseException
show Answer
a. NullPointerException
b. ArrayIndexOutOfBoundException
c. ArithmeticException
d. ParseException
show Answer
Ans. ArrayIndexOutOfBoundException
Q31. Checked exception needs to be ...
a. Caught
b. Method needs to declare that it throws these exception
c. Either A or B
d. Both A and B
show Answer
a. Caught
b. Method needs to declare that it throws these exception
c. Either A or B
d. Both A and B
show Answer
Ans. Either A or B
Q32. Collections.sort can only be performed on ..
a. Set
b. List
c. Map
d. Any Collection implementation
show Answer
a. Set
b. List
c. Map
d. Any Collection implementation
show Answer
Ans. List
Q33. Effective Java 6 , TreeMap implements ...
a. Map Interface
b. SortedMap Interface
c. NavigableMap Interface
d. SortedNavigableMap Interface
show Answer
a. Map Interface
b. SortedMap Interface
c. NavigableMap Interface
d. SortedNavigableMap Interface
show Answer
Ans. SortedMap Interface
Q34. Which of the following is not possible ?
a. try block followed by catch
b. try block followed by finally
c. try block followed by catch block and then finally
d. try block without catch or finally block
show Answer
a. try block followed by catch
b. try block followed by finally
c. try block followed by catch block and then finally
d. try block without catch or finally block
show Answer
Ans. try block without catch or finally block
Q35. Which of the following is not the difference between Singleton and Static class ( Class with static members only ) ?
a. Only one object can be created for Singleton class whereas No objects are created for static class.
b. Singleton class instance is initiated using new keyword whereas static class instance is created using static method.
c. Singleton class can be serialized whereas Static class cannot be.
d. Singleton Class can participate in runtime Polymorphism whereas Static class cannot.
show Answer
a. Only one object can be created for Singleton class whereas No objects are created for static class.
b. Singleton class instance is initiated using new keyword whereas static class instance is created using static method.
c. Singleton class can be serialized whereas Static class cannot be.
d. Singleton Class can participate in runtime Polymorphism whereas Static class cannot.
show Answer
Ans. Singleton class instance is initiated using new keyword whereas static class instance is created using static method.
Q36. Which of the following is false about main method ?
a. It should be declared public and static
b. it should have only 1 argument of type String array
c. We can override main method
d. We can overload main method
show Answer
a. It should be declared public and static
b. it should have only 1 argument of type String array
c. We can override main method
d. We can overload main method
show Answer
Ans. We can override main method
Q37. Which of the following is false about Constructors ?
a. Constructor can be overloaded
b. A no argument constructor is provided by the compiler if we declare only constructors with arguments.
c. Constructors shouldn't have any return types , not even void.
d. If super is not explicitly called, still super() is intrinsically added by the compiler.
show Answer
a. Constructor can be overloaded
b. A no argument constructor is provided by the compiler if we declare only constructors with arguments.
c. Constructors shouldn't have any return types , not even void.
d. If super is not explicitly called, still super() is intrinsically added by the compiler.
show Answer
Ans. A no argument constructor is provided by the compiler if we declare only constructors with arguments.
Q38. Variables of an interface are intrinsically ...
a. transient
b. final
c. public
d. static
show Answer
a. transient
b. final
c. public
d. static
show Answer
Ans. transient
Q39. Which of the following class creates mutable objects ?
a. Boolean
b. File
c. String
d. StringBuffer
show Answer
a. Boolean
b. File
c. String
d. StringBuffer
show Answer
Ans. StringBuffer
Q40. Which of the following is not true for final variables ?
a. They cannot be changed after initialization
b. They can be initialized within static method
c. They can be declared and initialized together at the same place
d. They can be initialized within constructor
show Answer
a. They cannot be changed after initialization
b. They can be initialized within static method
c. They can be declared and initialized together at the same place
d. They can be initialized within constructor
show Answer
Ans. They can be initialized within static method
Q41. Which of the following is false for final ?
a. Final methods cannot be overriden
b. Final methods cannot be overloaded
c. Final classes cannot be subclassed
d. Final class cannot be abstract
show Answer
a. Final methods cannot be overriden
b. Final methods cannot be overloaded
c. Final classes cannot be subclassed
d. Final class cannot be abstract
show Answer
Ans. Final methods cannot be overloaded
Q42. Invoking start twice on same thread leads to ..
a. ClassCastException
b. NullPointerException
c. InterruptedException
d. IllegalStateException
show Answer
a. ClassCastException
b. NullPointerException
c. InterruptedException
d. IllegalStateException
show Answer
Ans. IllegalStateException
Q43. Which of the following is false about var args ?
a. Var Args argument should have data type followed by three dots
b. Three dots should be consecutive and not separated by even space
c. We cannot have space before and after the dots
d. If there is a var args in the method, it should be only one and the last one.
show Answer
a. Var Args argument should have data type followed by three dots
b. Three dots should be consecutive and not separated by even space
c. We cannot have space before and after the dots
d. If there is a var args in the method, it should be only one and the last one.
show Answer
Ans. We cannot have space before and after the dots
Q44. Which of the following is not valid var args declaration ?
a. int sum (int... numbers)
b. int sum (.int .. numbers)
c. int sum (int ... numbers)
d. int sum (int x, int ... numbers)
show Answer
a. int sum (int... numbers)
b. int sum (.int .. numbers)
c. int sum (int ... numbers)
d. int sum (int x, int ... numbers)
show Answer
Ans. int sum (.int .. numbers)
Q45. Strings in switch were introduced in Which Java version ?
a. Java 5
b. Java 6
c. Java 7
d. Java
show Answer
a. Java 5
b. Java 6
c. Java 7
d. Java
show Answer
Ans. Java 6
Q46. Which of the following doesn't extend Collection interface ?
a. Set
b. List
c. Map
d. Queue
show Answer
a. Set
b. List
c. Map
d. Queue
show Answer
Ans. Map