Questions du site: www.geekinterview.com

 

 

What is the output of the following main program? public static void main(String[] args) { int x,y; a = 5; b = 1; while (a > 0) { a = a - 1; b = b * a; System.out.println(b); } }

-    55
     24
     24
     24
     0

-     5
     12
     12
     24
     24

-     4
     12
     24
     24
     0

- None of the Above

 

Command to execute a compiled java programs is

run

execute

javac

java

 

A method with name example() that has two integer arguments is declared as

public void example();

public void example(int x, y);

public void example(int x, int y);

public int example(x,y);

 

What is the output of the following program? public class example {    public static void main(String args[]) {    int x=0, y=2;    do {       x=++x;       y--;       } while(y>0);       System.out.println(x);    } }

0

1

2

Compilation Error

 

What is the output of the following piece of code? if(" String ".trim() == "String") System.out.println("Welcome"); else System.out.println("Good Bye");

The code will compile and print "Welcome"

The code will compile and print "Good Bye"

The code will cause a compiler error

 None of the Above

 

Choose the correct statement from the given choice?

Arrays in Java are essentially objects

It is not possible to assign one array to another. Individual elements of array can however be assigned.

 Array elements are indexed from 1 to size of array

 If a method tries to access an array element beyond its range, a compile warning is generated.

 

Which of the following statements are true?

The return type for a method can be any Java type, including void

An important principal of object oriented programming is implementation hiding

When you perform mathematical calculations on the unlike data type, java will perform a implicit conversion to unify the types

All the Above

 

When you add a float, int and byte the result will be

float

int

byte

double

 

What will happen when the class below is complied?

public class Example
{
   //char a = 'u000A';
}

Will not compile - complains on an invalid expression.

Will compile successfully but with a warning message.

Will complete successfully.

None of the Above

 

When you divide a number of type double by zero then the result will be

Zero

Double.NaN

Unpredictable

None of the Above

 

How can you ensure that the memory allocated by an object is freed?

By invoking the free method on the object

By calling system.gc() method

By setting all references to the object to new values (say null).

Garbage collection cannot be forced. The programmer cannot force the JVM to free the memory used by an object.

 

What is the base type of the array given below?
Color[] example = new Color[20];

Color

example

No base type

Both (A) and (B)

 

The 16 bit coding scheme employed in Java programming is

EDCDIC

UNICODE

ASCII

Hexadecimal

 

Consider the following piece of code byte x = 0; x += 1;

Results in x having the value 1.

Causes a compiler error.

Will require a cast (byte) before 1.

Will give syntax error.

 

What is the number of bytes used by Java primitive long?

The number of bytes is compiler dependent

2

4

8

 

Which of the function is used to convert String to Number in java program?

toNumber()

conString()

valueOf()

None of the Above

 

What is the output of the following code for exampleprint(1)?

static void exampleprint(int inputitem)
{    
if (inputitem == 0)
{       
System.out.print("*");    
}    
else
{       
System.out.print("[");       
exampleprint(inputitem - 1);       
System.out.print(",");       
exampleprint(inputitem - 1);       
System.out.println("]");    
}
}

 *,*,*

 [*,*]

*

None of the Above

 

The Java interpreter is used for the execution of the source code.

True

False

 

On successful compilation a file with the .exe extension is created.

True

False

 

The Java Program is enclosed in a class definition.

True

False

 

Class and main() methods declarations are required for every Java application?

True

False

 

What output is displayed as the result of executing the following statement?
System.out.println("// Looks like a comment.");

// Looks like a comment

The statement results in a compilation error

Looks like a comment

No output is displayed

 

In order for a source code file, containing the public class Test, to successfully compile, which of the following must be true?

It must have a package statement

It must be named Test.java

It must import java.lang

It must declare a public class named Test

 

Void is the return type of program’s main( ) method.

True

False

 

string array is the argument type of program’s main( ) method.

True

False

 

Consider the following program:
import myLibrary.*;
public class ShowSomeClass
{
//
code for the class...
}
What is the name of the java file containing this program?

myLibrary.java

ShowSomeClass.java

ShowSomeClass

ShowSomeClass.class

Any file name with the java suffix will do

 

Which of the following is TRUE?

 In java, an instance field declared public generates a compilation error.

 int is the name of a class available in the package java.lang

Instance variable names may only contain letters and digits.

A class has always a constructor (possibly automatically supplied by the java compiler).

The more comments in a program, the faster the program runs.

 

Consider the following code snippet
String river = new String(“Columbia”);
System.out.println(river.length());
What is printed?

6

7

8

Columbia

River

 

Consider
public class MyClass{
public MyClass(){/*code*/}
// more code...
}
To instantiate MyClass, you would write?

MyClass mc = MyClass;

MyClass mc = MyClass();

MyClass mc = new MyClass();

MyClass mc = new MyClass;

 

What is garbage collection in the context of Java?

The operating system periodically deletes all of the java files available on the system.

Any package imported in a program and not used is automatically deleted.

When all references to an object are gone, the memory used by the object is automatically reclaimed.

The JVM checks the output of any Java program and deletes anything that doesn't make sense.

Janitors working for Sun MicroSystems are required to throw away any Microsoft documentation found in the employees' offices.

 

 

You read the following statement in a Java program that compiles and executes.
submarine.dive(depth);
What can you say for sure?

depth must be an int

dive must be a method.

dive must be the name of an instance field.

submarine must be the name of a class

submarine must be a method.

 

The JVM has an automatic garbage collector that will reclaim the memory from any object that has been discarded by the running program.

True

False

 

A single-line comment begins with a ________ and ends at the end of the line

 /

 //

 /*

**

 

A method in Java, that calls itself is said to be recursive.

True

False

 

The Code in java is contained within Methods

True

False

 

The methods and variables defined within a class are called members of the class

True

False

 

If the method does not return a value, its return type must be void

True

False

 

Methods that have a return type other than void return a value to the calling routine using the following form of the return statement: return value;

True

False

 

In return value; value is the value returned.

True

False

 

The type of data returned by a method need not be compatible with the return type specified by the method

True

False

 

The variable receiving the value returned by a method must also be compatible with the return type specified for the method.

True

False

 

A parameter is a variable defined by a method that receives a value when the method is called.

True

False

 

In general, there are _________ ways that a computer language can pass an argument to a subroutine

One

Two

Three

Four

 

In the Call-by-value methods of passing an argument to a Subroutine, the value of an argument is copied into the formal parameter of the subroutine

True

False

 

Recursion is the process of defining something in terms of itself.

True

False

 

A variable declared as final prevents its contents from being modified

True

False

 

If you want to pass information into a program when you run it then command-line arguments are to main( ).

True

False

 

Java was conceived by __________

Microsoft

Oracle

Sun Microsystem

Intel

 

Java compiler is an executable code

True

False

 

____________ is a highly optimized set of instructions designed to be executed by the Java run-time system

Byte Code

Firewall

Tetra Code

View Code

 

Java run-time system is also called as Java Virtual Machine (JVM)

True

False

 

Java Virtual Machine is an interpreter for bytecode

True

False

 

Java is Architectural _____________

Dependent

Neutral

Independent

None of the above

 

Java enables the creation of cross-platform programs by compiling into an intermediate representation called Java ____________

Byte Code

Firewall

Tetra Code

View Code

 

Java is Not designed for the distributed environment of the Internet

True

False

 

Comments in Java Program must begin with /* and end with */

True

False

 

All statements in Java end with a _____________

Colon

SemiColon

Hypen

Dot

 

The simplest form of the for loop in Java is for(initialization; condition; iteration) statement;

True

False

 

You do not need to follow any special indentation rules in Java

True

False

 

Java is Case ________

Insensitive

Sensitive

 

A constant value in Java is created by using a literal representation of it

True

False

 

The Separator [ ] is Used to declare array types

True

False

 

The print( ) method is just like println( ), except that it does not output a newline character after each call

True

False

 

The Java interpreter is used for the execution of the source code.

True

False

 

State true or false :- On successful compilation a file, with the .class extension is created.

True

False

 

Which of the option correctly describes the comments in java 1) // -- single line comment 2) /* -- */ multiple line comment 3) /** -- */ documentation

 1, 2

 2, 3

 3, 1

 1, 2, 3

 

Which of the following declare an array of string objects? (Select Multiple)

String[ ] s;

String [ ]s:

String[ s]:

String s[ ]:

 

Which of the following are primitive types?

byte

String

integer

float

 

What is the value of 111 % 13?

3

5

7

9

 

State true or false :- The do-while loop repeats a set of code at least once before the condition is tested.

True

False

 

State true or false :- All the classes in java.lang package are automatically imported when a program is compiled.

True

False

 

Which of the following features are common to both Java & C++? (Select multiple)

The class declaration

The access modifiers

The encapsulation of data & methods with in objects

The use of pointers

 

You would use the ____ operator to create a single instance of a named class.

New

dot

equals

none of the above

 

Java compiler stores the .class files in the path specified in CLASSPATH environmental variable.

True

False

 

Which of the following methods cause the String object referenced by s to be changed? (Select multiple)

s.concat( )

s.toUpperCase( )

s.replace( )

s.valueOf( )

 

Which of these is the correct format to use to create the literal char value a?

 'a'

"a"

new Character(a)

\000a

 

What will be the result of compiling the following code: public class Test { static int age; public static void main (String args []) { age = age + 1; System.out.println("The age is " + age); } }

Compiles and runs with no output

Compiles and runs printing out The age is 1

Compiles but generates a runtime error

Does not compile

Compiles but generates a compile time error