Java Fundamental Test Questions

) What is meant by variable?
Ans: Variables are locations in memory that can hold values. Before assigning any value to a variable, it must be declared. 

2) What are the kinds of variables in Java? What are their uses?
Ans: Java has three kinds of variables namely, the instance variable, the local variable and the class variable. 
Local variables are used inside blocks as counters or in methods as temporary variables and are used to store information needed by a single method. 
Instance variables are used to define attributes or the state of a particular object and are used to store information needed by multiple methods in the objects. 
Class variables are global to a class and to all the instances of the class and are useful for communicating between different objects of all the same class or keeping track of global states. 

3) How are the variables declared?
Ans: Variables can be declared anywhere in the method definition and can be initialized during their declaration.They are commonly declared before usage at the beginning of the definition. 
Variables with the same data type can be declared together. Local variables must be given a value before usage. 

4) What are variable types?
Ans: Variable types can be any data type that java supports, which includes the eight primitive data types, the name of a class or interface and an array. 

5) How do you assign values to variables?
Ans: Values are assigned to variables using the assignment operator =. 

6) What is a literal? How many types of literals are there?
Ans: A literal represents a value of a certain type where the type describes how that value behaves.There are different types of literals namely number literals, character literals, boolean literals, string literals,etc. 

7) What is an array?
Ans: An array is an object that stores a list of items. 
8) How do you declare an array?
Ans: Array variable indicates the type of object that the array holds. 
Ex: int arr[]; 

9) Java supports multidimensional arrays.
Ans: a. 
10) An array of arrays can be created.
Ans: a. 
11) What is a string?
Ans: A combination of characters is called as string. 

12) Strings are instances of the class String.
Ans: a. 
13) When a string literal is used in the program, Java automatically creates instances of the string class.
Ans: a. 

14) Which operator is to create and concatenate string?
Ans: Addition operator(+). 
15) Which of the following declare an array of string objects?
1.         String[ ] s;
2.         String [ ]s:
3.         String[ s]:
4.         String s[ ]:
Ans : a, b and d 
16) What is the value of a[3] as the result of the following array declaration?
1.            1
2.            2
3.            3
4.            4
Ans : d 
17) Which of the following are primitive types?
1.            byte
2.            String
3.            integer
4.            Float
Ans : a. 
18) What is the range of the char type?
1.               0 to 2 16
2.               0 to 2 15
3.               0 to 2 16-1
4.               0 to 2 15-1
Ans. d 
19) What are primitive data types?
Ans : byte, short, int, long 
float, double 
20) What are default values of different primitive types?

Ans : 
int - 0 
short - 0 
byte - 0 
long - 0 l 
float - 0.0 f 
double - 0.0 d 
boolean - false 
char - null 
21) Converting of primitive types to objects can be explicitly.

Ans: b. 
22) How do we change the values of the elements of the array?
Ans : The array subscript expression can be used to change the values of the elements of the array. 
23) What is final varaible?

Ans : If a variable is declared as final variable, then you can not change its value. It becomes constant. 
24) What is static variable?

Ans : Static variables are shared by all instances of a class. 

 Java  Operators
1) What are operators and what are the various types of operators available in Java?
Ans: Operators are special symbols used in expressions. The following are the types of operators:
Arithmetic operators,
Assignment operators,
Increment & Decrement operators,
Logical operators,
Biwise operators,
Comparison/Relational operators and
Conditional operators
2) The ++ operator is used for incrementing and the -- operator is used for
Ans: a.
3) Comparison/Logical operators are used for testing and magnitude.
Ans: a.
4) Character literals are stored as unicode characters.
Ans: a.
5) What are the Logical operators?
Ans: OR(|), AND(&), XOR(^) AND NOT(~).
6) What is the % operator?
Ans : % operator is the modulo operator or reminder operator. It returns the reminder of dividing the first operand by second operand.
7) What is the value of 111 % 13?
1.       3
2.       5
3.       7
4.       9
Ans : c.
8) Is &&= a valid operator?
Ans : No.
9) Can a double value be cast to a byte?
Ans : Yes
10) Can a byte object be cast to a double value ?
Ans : No. An object cannot be cast to a primitive value.
11) What are order of precedence and associativity?
Ans : Order of precedence the order in which operators are evaluated in expressions.
Associativity determines whether an expression is evaluated left-right or right-left.
12) Which Java operator is right associativity?
Ans : = operator.
13) What is the difference between prefix and postfix of -- and ++ operators?
Ans : The prefix form returns the increment or decrement operation and returns the value of the increment or decrement operation.
The postfix form returns the current value of all of the expression and then
performs the increment or decrement operation on that value.
14) What is the result of expression 5.45 + "3,2"?
1)The double value 8.6
2)The string ""8.6"
3)The long value 8.
4)The String "5.453.2"
Ans : d
15) What are the values of x and y ?
x = 5; y = ++x;
Ans : x = 6; y = 6
16) What are the values of x and z?
x = 5; z = x++;
Ans : x = 6; z = 5

4) Compilation and output of "Not equal! 10"
The output will be "Not equal 10".  This illustrates that the Output +=10 calculation was never performed because processing stopped after the first operand was evaluated to be false. If you change the value of b1 to true processing occurs as you would expect and the output is "We are equal 20";.
16)Given the following variables
123456789123456789char c = 'c';

int i = 10;

double d = 10;

long l = 1;

String s = "Hello";
Which of the following will compile without error?
Ans  2.
Classes  and Methods

1).What will happen when you attempt to compile and run this code?
class Base{

        abstract public void myfunc();

        public void another(){

        System.out.println("Another method");



public class Abs extends Base{

        public static void main(String argv[]){

        Abs a = new Abs();



        public void myfunc(){

                System.out.println("My func");


        public void amethod(){




1) The code will compile and run, printing out the words "My Func"
2) The compiler will complain that the Base class is not declared as abstract.
3) The code will compile but complain at run time that the Base class has non abstract methods
4) The compiler will complain that the method myfunc in the base class has no body, nobody at all to looove it

Ans -2) The compiler will complain that the Base class is not declared as abstract.
If a class contains abstract methods it must itself be declared as abstract

2) The new operator creates a single instance named class and returns a reference to that object.
Ans: a.
3) A class is a template for multiple objects with similar features.
Ans: a.
4) What is meant by garbage collection?
Ans: When an object is no longer referred to by any variable, Java automatically reclaims the memory used by that object. This is known as garbage collection.
5) What are methods and how are they defined?
Ans: Methods are functions that operate on instances of classes in which they are defined.Objects can communicate with each other using methods and can call methods in other classes.
Method definition has four parts. They are name of the method, type of object or primitive type the method returns, a list of parameters and the body of the method. A method's signature is a combination of the first three parts mentioned above.
6) What is calling method?
Ans: Calling methods are similar to calling or referring to an instance variable. These methods are accessed using dot notation.
Ex: obj.methodname(param1,param2)
7) Which method is used to determine the class of an object?
Ans: getClass( ) method can be used to find out what class the belongs to. This class is defined in the object class and is available to all objects.
8)Given the following class definition, which of the following statements would be legal after the comment //Here
class InOut{

String s= new String("Between");
        public void amethod(final int iArgs){
       int iam;
              class Bicycle{
                       public void sayHello(){
                }//End of bicycle class
        }//End of amethod
       public void another(){
       int iOther;

1) System.out.println(s);
2) System.out.println(iOther);
3) System.out.println(iam);
4) System.out.println(iArgs);
Ans – 1) System.out.println(s);
       4) System.out.println(iArgs);
A class within a method can only see final variables of the enclosing method. However it the normal visibility rules apply for variables outside the enclosing method.

9) How can class be imported to a program?
Ans: To import a class, the import keyword should be used as shown.;
import classname;
10) How can class be imported from a package to a program?
Ans: import java . packagename . classname (or) import java.package name.*;
11) What is a constructor?
Ans: A constructor is a special kind of method that determines how an object is initialized when created.
12) Which keyword is used to create an instance of a class?
Ans: new.
13) Which method is used to garbage collect an object?
Ans: finalize ().
14) Constructors can be overloaded like regular methods.
Ans: a.
15) What is casting?
Ans: Casting is bused to convert the value of one type to another.
16) Casting between primitive types allows conversion of one primitive type to another.
Ans: a.
17) Casting occurs commonly between numeric types.
Ans: a.
18) Boolean values can be cast into any other primitive type.
Ans: b.
19) Casting does not affect the original object or value.
Ans: a.
20) Which cast must be used to convert a larger value into a smaller one?
Ans: Explicit cast.
21) Which cast must be used to cast an object to another class?
Ans: Specific cast.
22) Which of the following features are common to both Java & C++?
A.The class declaration
b.The access modifiers
c.The encapsulation of data & methods with in objects
d.The use of pointers
Ans: a,b,c.
23) Which of the following statements accurately describe the use of access modifiers within a class definition?
a.They can be applied to both data & methods
b.They must precede a class's data variables or methods
c.They can follow a class's data variables or methods
d.They can appear in any order
e.They must be applied to data variables first and then to methods
Ans: a,b,d.
24) Suppose a given instance variable has been declared private. Can this instance variable be manipulated by methods out side its class?
Ans: b.
25) Which of the following statements can be used to describe a public method?
a.It is accessible to all other classes in the hierarchy
b.It is accessablde only to subclasses of its parent class
c.It represents the public interface of its class
d.The only way to gain access to this method is by calling one of the public class
Ans: a,c.
26) Which of the following types of class members can be part of the internal part of a class?
a.Public instance variables
b.Private instance variables
c.Public methods
d.Private methods
Ans: b,d.
27) You would use the ____ operator to create a single instance of a named class.
Ans: a.
28) Which of the following statements correctly describes the relation between an object and the instance variable it stores?
a.Each new object has its own distinctive set of instance variables
b.Each object has a copy of the instance variables of its class
c.the instance variable of each object are seperate from the variables of other objects
d.The instance variables of each object are stored together with the variables of other objects
Ans: a,b,c.
29) If no input parameters are specified in a method declaration then the declaration will include __. empty set of parantheses
b.the term void
Ans: a.
30) What are the functions of the dot(.) operator?
a.It enables you to access instance variables of any objects within a class
b.It enables you to store values in instance variables of an object
c.It is used to call object methods
d.It is to create a new object
Ans: a,b,c.
31) Which of the following can be referenced by this variable?
a.The instance variables of a class only
b.The methods of a class only
c.The instance variables and methods of a class
Ans: c.
32) The this reference is used in conjunction with ___methods.
Ans: b.
33) Which of the following operators are used in conjunction with the this and super references?
a.The new operator
b.The instanceof operator
c.The dot operator
Ans: c.
34) A constructor is automatically called when an object is instantiated
a. true
b. false
Ans: a.
35) When may a constructor be called without specifying arguments?
a. When the default constructor is not called
b. When the name of the constructor differs from that of the class
c. When there are no constructors for the class
Ans: c.
36) Each class in java can have a finalizer method
a. true
Ans: a.
37) When an object is referenced, does this mean that it has been identified by the finalizer method for garbage collection?
Ans: b.
38) Because finalize () belongs to the java.lang.Object class, it is present in all ___.
Ans: b.
39) Identify the true statements about finalization.
a.A class may have only one finalize method
b.Finalizers are mostly used with simple classes
c.Finalizer overloading is not allowed
Ans: a,c.
40) When you write finalize() method for your class, you are overriding a finalizer inherited from a super class.
Ans: a.
41) Java memory management mechanism garbage collects objects which are no longer referenced
a true
Ans: a.
42) are objects referenced by a variable candidates for garbage collection when the variable goes out of scope?
a yes
b. no
Ans: a.
43) Java's garbage collector runs as a ___ priority thread waiting for __priority threads to relinquish the processor.
Ans: a,b.
44) The garbage collector will run immediately when the system is out of memory
Ans: a.
45) You can explicitly drop a object reference by setting the value of a variable whose data type is a reference type to ___
Ans: null
46) When might your program wish to run the garbage collecter?
a. before it enters a compute-intense section of code
b. before it enters a memory-intense section of code
c. before objects are finalized
d. when it knows there will be some idle time
Ans: a,b,d
47) For externalizable objects the class is solely responsible for the external format of its contents
Ans: a
48) When an object is stored, are all of the objects that are reachable from that object stored as well?
Ans: a
49) The default__ of objects protects private and trancient data, and supports the __ of the classes
Ans: b,a.
50) Which are keywords in Java?
b) sizeof
c) friend
d) extends
e) synchronized
Ans : d and e
51) When must the main class and the file name coincide?
Ans :When class is declared public.
52) What are different modifiers?
Ans : public, private, protected, default, static, trancient, volatile, final, abstract.
53) What are access modifiers?
Ans : public, private, protected, default.
54) What is meant by "Passing by value" and " Passing by reference"?
Ans : objects – pass by referrence
55)Methods - pass by value Given the following class definition which of the following can be legally placed after the comment line
//Here ?
class Base{
public Base(int i){}

public class MyOver extends Base{
public static void main(String arg[]){
                MyOver m = new MyOver(10);
        MyOver(int i){

        MyOver(String s, int i){
1)MyOver m = new MyOver();
4)Base b = new Base(10);
4)Base b = new Base(10);
Any call to this or super must be the first line in a constructor. As the method already has a call to this, no more can be   inserted.

56) What modifiers may be used with top-level class?
Ans : public, abstract, final.
57) What is an example of polymorphism?
   1.      Inner class
   2.      Anonymous classes
  3.      Method overloading
   4.      Method overriding
Ans : c

Control  Statements

1) What are the programming constructs?
a) Sequential
b) Selection -- if and switch statements
c) Iteration -- for loop, while loop and do-while loop
2) class conditional {
public static void main(String args[]) {
int i = 20;
int j = 55;
int z = 0;
z = i < j ? i : j; // ternary operator
System.out.println("The value assigned is " + z);
What is output of the above program?
Ans: The value assigned is 20
3) The switch statement does not require a break.
Ans: b.
4) The conditional operator is otherwise known as the ternary operator.
Ans: a.
5) The while loop repeats a set of code while the condition is false.
Ans: b.
6) The do-while loop repeats a set of code atleast once before the condition is tested.
Ans: a.
7) What are difference between break and continue?
Ans: The break keyword halts the execution of the current loop and forces control out of the loop.
The continue is similar to break, except that instead of halting the execution of the loop, it starts the next iteration.
8) The for loop repeats a set of statements a certain number of times until a condition is matched.
Ans: a.
9) Can a for statement loop indefintely?
Ans : Yes.
10) What is the difference between while statement and a do statement/
Ans : A while statement checks at the beginning of a loop to see whether the next loop iteration should occur.
A do statement checks at the end of a loop to see whether the next iteration of a loop should occur. The do statement will always execute the body of a loop at least once.

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What is the Collections API?
 Answers:The Collections API is a set of classes and interfaces that support operations on collections of objects.

 2. What is the List interface?
 Answers:The List interface provides support for ordered collections of objects

 3. What is an Iterator interface?
 Answers:The Iterator interface is used to step through the elements of a Collection.

4. What  is   Collectios and Collection?
 Answer: Collection is class and Collection is Inerface

5. Which class does not override the equals() and hashCode() methods, inheriting them directly from class Object?







Answer: Option C
6. Which  Map  is use   to get  sorted order  of its key .

 Answer: TreeMap.

7.Which collection class allows you to grow or shrink its size and provides indexed access to its elements, but whose methods are not synchronized?
 Answer: Option d

8. Which   is   prefer   to use  SynchronizeHashmap() or  ConcurrentHasMap().
 Answer: Concurrent due  to performance.

9. Which  does not allow  duplicate elements List orSet?
Answer: Set .

10.Which interface does java.util.Hashtable implement?
Answer: Option a

11. What  are  Collections Interfaces ?
Answers: List ,Set ,Map, Collection ,Queue ,Dqueue ,SortedMap,Iterator
12. What are important  Collections Classes ?
Answers: ArrayList , HashMap,HashSet ,Hashtable , Hashset ,EnumSet etc

Java Fundamental Test Questions Java   Fundamental   Test  Questions Reviewed by Mukesh Jha on 3:31 AM Rating: 5

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