Java Language Fundamental - Quiz

Q: Java is a _________ language.

A. weakly typed
B. strogly typed
C. moderate typed
D. None of these

Correct Option: B
Remarks:

Explanation:

Java is a strongly typed language. This means that the type of a variable is known at compile time and once a variable is declared with a certain type, it cannot be assigned a value of a different type without an explicit cast.

Q: Which one of these lists contains only Java programming language keywords?

A. class, if, void, long, Int, continue
B. goto, instanceof, native, finally, default, throws
C. try, virtual, throw, final, volatile, transient
D. strictfp, constant, super, implements, do

Correct Option: B
Remarks:

Explanation:

All the words in option B are among the 49 Java keywords. Although goto reserved as a keyword in Java, goto is not used and has no function.

Option A is wrong because the keyword for the primitive int starts with a lowercase i.

Option C is wrong because "virtual" is a keyword in C++, but not Java.

Option D is wrong because "constant" is not a keyword. Constants in Java are marked static and final.

Option E is wrong because "include" is a keyword in C, but not in Java.

Q: Which one of the following will declare an array and initialize it with five numbers?

A. Array a = new Array(5);
B. int [] a = {23,22,21,20,19};
C. int a [] = new int[5];
D. int [5] array;

Correct Option: B
Remarks:

Explanation:

Option B is the legal way to declare and initialize an array with five elements.

Option A is wrong because it shows an example of instantiating a class named Array, passing the integer value 5 to the object's constructor. If you don't see the brackets, you can be certain there is no actual array object! In other words, an Array object (instance of class Array) is not the same as an array object.

Option C is wrong because it shows a legal array declaration, but with no initialization.

Option D is wrong (and will not compile) because it declares an array with a size. Arrays must never be given a size when declared.

Q: Which is the valid declarations within an interface definition?

A. public double methoda();
B. public final double methoda();
C. static void methoda(double d1);
D. protected void methoda(double d1);

Correct Option: A
Remarks:

Explanation:

Option A is correct. A public access modifier is acceptable. The method prototypes in an interface are all abstract by virtue of their declaration, and should not be declared abstract.

Option B is wrong. The final modifier means that this method cannot be constructed in a subclass. A finalmethod cannot be abstract.

Option C is wrong. static is concerned with the class and not an instance.

Option D is wrong. protected is not permitted when declaring a method of an interface. See information below.

Member declarations in an interface disallow the use of some declaration modifiers; you cannot use transient, volatile, or synchronized in a member declaration in an interface. Also, you may not use the private and protected specifiers when declaring members of an interface.

Q:

public class F0091 
{    
    public void main( String[] args ) 
    {  
        System.out.println( "Hello" + args[0] ); 
    } 
}

What will be the output of the program, if this code is executed with the command line: > java F0091 world

A. Hello
B. Hello Foo91
C. Hello world
D. The code does not run.

Correct Option: D
Remarks:

Explanation:

Option D is correct. A runtime error will occur owning to the main method of the code fragment not being declared static:

Exception in thread "main" java.lang.NoSuchMethodError: main

The Java Language Specification clearly states: "The main method must be declared public, static, and void. It must accept a single argument that is an array of strings."

Q: What will be the output of the program?

public class CommandArgsTwo 
{
    public static void main(String [] argh) 
    {
        int x;
        x = argh.length;
        for (int y = 1; y <= x; y++) 
        {
            System.out.print(" " + argh[y]);
        }
    }
}

and the command-line invocation is

> java CommandArgsTwo 1 2 3

A. 0 1 2
B. 1 2 3
C. 0 0 0
D. An exception is thrown at runtime

Correct Option: D
Remarks:

Explanation:

An exception is thrown because at some point in (System.out.print(" " + argh[y]);), the value of x will be equal to y, resulting in an attempt to access an index out of bounds for the array. Remember that you can access only as far as length - 1, so loop logical tests should use x < someArray.length as opposed to x < = someArray.length.

Q: In the given program, how many lines of output will be produced?


public class Test 
{
    public static void main(String [] args) 
    {
    int [] [] [] x = new int [3] [] [];
    int i, j;
    x[0] = new int[4][];
    x[1] = new int[2][];
    x[2] = new int[5][];
    for (i = 0; i < x.length; i++)
    {
        for (j = 0; j < x[i].length; j++) 
        {
            x[i][j] = new int [i + j + 1];
            System.out.println("size = " + x[i][j].length);
        }
    }
    }
}

A. 7
B. 9
C. 11
D. 13

Correct Option: C
Remarks:

Explanation:

The loops use the array sizes (length).

It produces 11 lines of output as given below.

D:\Java>javac Test.java

D:\Java>java Test
size = 1
size = 2
size = 3
size = 4
size = 2
size = 3
size = 3
size = 4
size = 5
size = 6
size = 7

Therefore, 11 is the answer.

Q: What will be the output of the program?

 
public class X 
{
    public static void main(String [] args) 
    {
        String names [] = new String[5];
        for (int x=0; x < args.length; x++)
            names[x] = args[x];
        System.out.println(names[2]);
    }
}

and the command line invocation is

A. names
B. null
C. Compilation fails
D. An exception is thrown at runtime

Correct Option: B
Remarks:

Explanation:

The names array is initialized with five null elements. Then elements 0 and 1 are assigned the String values "a" and "b" respectively (the command-line arguments passed to main). Elements of names array 2, 3, and 4 remain unassigned, so they have a value of null.

Q: Number of primitive data types in Java are?

A. 2
B. 4
C. 10
D. 8

Correct Option: D
Remarks:

Explanation: There are 8 types of primitive data types- int, char, boolean, byte, long, float, short, double.

Q: Can one block of except statements handle multiple exceptions?

A. No, Multiple exceptions cannot be handled in a single block
B. Yes, likeexcept [ NameError, SyntaxError, ...]
C. Yes, likeexcept NameError, SyntaxError, …
D. Yes, likeexcept ( NameError, SyntaxError, ...)

Correct Option: D
Remarks:

Explanation:

Yes, like


except ( NameError, SyntaxError, ...)

Java Language Fundamental - Quiz

Java is a _________ language.

Which one of these lists contains only Java programming language keywords?

Which one of the following will declare an array and initialize it with five numbers?

Which is the valid declarations within an interface definition?

public class F0091 { public void main( String[] args ) { System.out.println( "Hello" + args[0] ); } }
What will be the output of the program, if this code is executed with the command line: > java F0091 world

What will be the output of the program?
public class CommandArgsTwo { public static void main(String [] argh) { int x; x = argh.length; for (int y = 1; y <= x; y++) { System.out.print(" " + argh[y]); } } }

and the command-line invocation is

> java CommandArgsTwo 1 2 3

In the given program, how many lines of output will be produced?

What will be the output of the program?

and the command line invocation is

Number of primitive data types in Java are?

Can one block of except statements handle multiple exceptions?

Java Language Fundamental - Quiz

Java is a _________ language.

Which one of these lists contains only Java programming language keywords?

Which one of the following will declare an array and initialize it with five numbers?

Which is the valid declarations within an interface definition?

public class F0091 { public void main( String[] args ) { System.out.println( "Hello" + args[0] ); } } What will be the output of the program, if this code is executed with the command line: > java F0091 world

What will be the output of the program? public class CommandArgsTwo { public static void main(String [] argh) { int x; x = argh.length; for (int y = 1; y <= x; y++) { System.out.print(" " + argh[y]); } } } and the command-line invocation is > java CommandArgsTwo 1 2 3

What will be the output of the program? public class X { public static void main(String [] args) { String names [] = new String[5]; for (int x=0; x < args.length; x++) names[x] = args[x]; System.out.println(names[2]); } } and the command line invocation is

Number of primitive data types in Java are?

Can one block of except statements handle multiple exceptions?

public class F0091 { public void main( String[] args ) { System.out.println( "Hello" + args[0] ); } }
What will be the output of the program, if this code is executed with the command line: > java F0091 world

What will be the output of the program?
public class CommandArgsTwo { public static void main(String [] argh) { int x; x = argh.length; for (int y = 1; y <= x; y++) { System.out.print(" " + argh[y]); } } }

and the command-line invocation is

> java CommandArgsTwo 1 2 3

What will be the output of the program?

and the command line invocation is