Core Java New MCQ

 

1. Which one of the following is true for Java
A) Java is object-oriented and  interpreted
B) Java is efficient and faster than C
C) Java is the choice of everyone.
D) Java is not robust.

Ans-A

 

 

2. The command javac is used to
A) debug a java program
B) compile a java program
C) interpret a java program
D) execute a java program

Ans-B

 

 

3. Which is the root class of all AWT events
A) java.awt.ActionEvent
B) java.awt.AWTEvent
C) java.awt.event.AWTEvent
D) java.awt.event.Event

Ans-B

 

 

4. OOP features are
i) Increasing productivity ii) Reusability
iii) Decreasing maintenance cost iv) High vulnerability
A) 1,2 & 4
B) 1,2 & 3
C) 1, 2 & 4
D) only 1

Ans-B

 

 

5. break statement is used to
i) get out of method ii) end a program
iii) get out of a loop iv) get out of the system
A) 1 & 2
B) 1,2 & 3
C) 1 & 3
D) 3

Ans D

 

 

6. Native-protocol pure Java converts ……….. into the ………… used by DBMSs directly.
A) JDBC calls, network protocol
B) ODBC class, network protocol
C) ODBC class, user call
D) JDBC calls, user call

Ans-A

 

 

7. Which of the following is true about Java.
A) Java does not support overloading.
B) Java has replaced the destructor function of C++
C) There are no header files in Java.
D) Java Support overriding

A.only A

B.only B

C.A,B,C

D.only D

Ans-.C

 

 

8. ……………. are not machine instructions and therefore, Java interpreter generates machine code that can be directly executed by the machine that is running the Java program.
A) Compiled Instructions
B) Compiled code
C) byte code
D) Java mid code

Ans-C

 

 

9. The command javac
A) Converts a java program into binary code
B) Converts a java program into bytecode
C) Converts a java program into machine language
D) Convert a java program into hardware

Ans-B

 

10. Which of the following is not the Java primitive type
A) Byte
B) Float
C) Character
D) Long double

Ans-D

 

 

11. Command to execute compiled java program is
A) java
B) javac
C) run
D) javaw

Ans-A

12. Inner classes are
A) anonymous classes
B) nested classes
C) subclasses
D) derived classes

Ans-B

13. All Java classes are derived from
A) java.lang.Class
B) java.util.Name
C) java.lang.Object
D) java.awt.Window

Ans-C

 

 

14. The jdb is used to
A) Create a jar archive
B) Debug a java program
C) Create a C header file
D) Generate java documentation

Ans-B

15. Which of the following is not a Java features?

      a           Dynamic

b.        Architecture Neutral

c.         Use of pointers

d.        Object-oriented

Ans-C

16. The \u0021 article referred to as a

      a.     Unicode escape sequence

b.     Octal escape

c.     Hexadecimal

d.     Line feed

Ans-A

17. Which of the following is a valid declaration of a char?

     a.   char ch = '\utea';

b.     char ca = 'tea';

c.     char cr = \u0223;

d.     char cc = '\itea';

Ans-A

18. What is the return type of the hashCode() method in the Object class?

      a.   Object

b.     int

c.     long

d.     void

Ans-B

 

19. What does the expression float a = 35 / 0 return?

      a.      0

b.     Not a Number

c.     Infinity

d.     Run time exception

Ans-C

20. Which of the following creates a List of 3 visible items and multiple selections abled?

      a.     new List(false, 3)

b.     new List(3, true)

c.     new List(true, 3)

d.     new List(3, false)

Ans-B

21. Which method will a web browser call on a new applet?

A) main method
B) destroy method
C) execute method
D) init method

Ans-D

22.  When a programming class implements an interface, it must provide behavior for

A) two methods defined in that interface
B) any methods in a class
C) only certain methods in that interface
D) all methods defined in that interface

 

23. In Java, …………. can only test for equality, whereas ………… can evaluate any type of Boolean expression.
A) switch, if
B) if, switch
C) if, break
D) continue, if

Ans-D

 

24. The third type of comment is used by a tool called ……………… for automatic generation of documentation.
A) Java commenting
B) Java generator
C) Java doc
D) Java loc

Ans-c

25. The class at the top of exception class hierarchy is ……………………..
A) ArithmeticException
B) Throwable
C) Class
D) Exception

Ans-B

26. Which package contains the Random class?

      a.    java.util package

b.     java.lang package

c.     java.awt package

d.     java.io package

Ans-A

27. Which option is false about the final keyword?

      a.     A final method cannot be overridden in its subclasses.

b.     A final class cannot be extended.

c.     A final class cannot extend other classes.

d.     A final method can be inherited.

Ans-C

 

28. Which of the following is a reserved keyword in Java?

     a.     object

b.     strictfp

c.     main

d.     system

Ans-B

 

29. Which keyword is used for accessing the features of a package?

      a.     package

b.     import

c.     extends

d.     export

Ans-B

 

30. Which of the given methods are of Object class?

     a.     notify(), wait( long msecs ), and synchronized()

b.     wait( long msecs ), interrupt(), and notifyAll()

c.     notify(), notifyAll(), and wait()

d.     sleep( long msecs ), wait(), and notify()

Ans-C

 

31. A package is a collection of

A) classes
B) interfaces
C) editing tools
D) classes and interfaces

Ans-D

 

32.  The concept of multiple inheritances is implemented in Java by
A) extending two or more classes
B) extending one class and implementing one or more interfaces
C) implementing two or more interfaces
D) both B and C

Ans-D

 

33. Which of the following do not represent legal flow control statements?
A) break;
B) return;
C) exit();
D) continue outer;

Ans-C

 

34. Which of the following is a mutable class in java?

      a.    java.lang.String

b.     java.lang.Byte

c.     java.lang.Short

d.     java.lang.StringBuilder

Ans-D

35. Using which keyword we can access the value of the instance variables and class variables of that class inside the method of that class itself.

A) super

B) final

C) this

D) either super or this

Ans-C

36. 1. In java a ………………….. is a sequence of characters.

A) string

B) arrayChar

C) groupChar

D) collection

Ans :B

37. . Java programs perform I/O through ………..

A) I/O methods

B) I/O package

C) streams

D) compiler

38. The default package that is implicitly called in a java program is ………….

A) java. Lang

B) java.System

C) java. Window

D) java.Lang.System

39.  What is the file extension of a compiled java program?

A) .class

B) .java

C) .css

D) .html

40.  ……………… keyword is used to invoke the current object.

A) New

B) That

C) This

D) Me

41.  Which of the function is used to convert string to Number in java program?

A) to Number()

B) conString()

C) valueOf()

D) toString()

42.  Which of this keyword can be used in a subclass to call the constructor of superclass?
a) super
b) this
c) extent
d) extends

43. Which of these is correct way of calling a constructor having no parameters, of superclass A by subclass B?
a) super(void);
b) superclass.();
c) super.A();
d) super();

44. Which of these is supported by method overriding in Java?
a) Abstraction
b) Encapsulation
c) Polymorphism
d) None of the mentioned

45. What keyword is used to explicitly raise a exception?

a)catch    

b)throw

c)throws

d)raise

46. What block is always executed, independently of a exception being raised?

a)throws

b)finally

c)catch

d)throw

47. Which of these is not a interface in the Collections Framework?

a)Collection

b)Group

c)Set

d)List

48. Which provides better performance for the insertion and removal from the middle of the list?

a)Vector

b)ArrayList

c)LinkedList

d)HashMap)

49. From the following statements which is a disadvantage of an java array?
a. An array can hold primitive types data

b. An array has its size that is known as array length

c. An array knows only its type that it contains. Array type is checked at the compile-time

d. An array holds only one type of data

50. How many reserved keywords are currently defined in the Java language?
a. 48

b. 49

c. 50

d. 47

51. Which method of string class in java is used to convert the boolean into String?
a. public static String valueOf(double I)

b. public static String valueOf(boolean I)

c. public boolean equals(Object anObject)

d. public static String valueOf(Object obj)

 

52.   Which keyword is used for the block to handle the exceptions generated by try block?
a. Catch

b. Final

c. throw

d. try

53. Which is a technique in Java in which a class can have any number of constructors that differ in parameter lists?

a. Constructor overloading

b. Method overloading

c. Operator overloading

d.Method overriding

54.  The life cycle of an applet is described by ……………… methods.

A) six

B) three

C) four

D) five

55.  …….. statement is valid for array declaration.

A. int number();

B. float number();

C. float number[];

D. count int[];

56. ……. operators which concatenates two strings.

A. +      

B. ++

C. –

D. +-

57. A …….. class may not have any abstract method.

A. abstract

B. static

C. final

D. public

58.  Which of the following is a valid syntax to synchronize the HashMap?

a.             Map m = hashMap.synchronizeMap();

b.     HashMap map =hashMap.synchronizeMap();

c.      Map m1 = Collections.synchronizedMap(hashMap);

d.     Map m2 = Collection.synchronizeMap(hashMap);

Ans-C