This document contains 15 multiple choice questions about Java programming concepts like classes, arrays, methods, and data types. It tests knowledge of topics like compiling Java files, using the Scanner class, initializing arrays, calling static methods, and parsing strings to integers.
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1: The .class extension on a file means that the file
a.contains Java source code.
b.contains HTML.
c.is produced by the Java compiler (javac).
d.contains a machine specific executable image.
2: Which command compiles the Java source code file
Welcome.java?
a.cd Welcome.java
b.javac Welcome.java
c.java Welcome.java
d.compile Welcome.java
3: A(n) ________ enables a program to read data from the
user.
a.printf
b.import declaration
c.Scanner
d.main routine
4: Which of the following is a Scanner method?
a.nextLine
b.nextText
c.nextWord
d.readNext
5: Every Java application is required to have
a. at least one public static method.
2. b.at least one data member.
c. a String variable which holds the name of the application.
d.a content pane and several GUI components.
6: Which of the following statements about creating arrays
and initializing their elements is false?
a. The new keyword should be used to create an array.
b. When an array is created, the number of elements must be
placed in square brackets following the type of element being
stored.
c. The elements of an array have unknown values just after the
array has been created.
d. A for loop is an excellent way to initialize the elements of
an array.
7: Assume the following class declaration.
class MyClass
{
int a;
String q;
public void firstMethod()
{
int b, ;
* 7;
+ c * a;
}
}
Mark the following statements as TRUE or FALSE.
q is a reference variable which refers to the empty string.
__TRUE___ b and c are local variables. ___TRUE____ a, b,
and c are primitive data types. ___FALSE____ MyClass is a
Java application. ___FALSE____
8: Which statement below could be used to randomly select a
state from an array which contains exactly 50 strings which
are the names of the states?
3. 1 + ( int ) ( Math.random( ) * 49 ); ( int ) ( Math.random( ) *
51 ); ( int ) ( Math.random( ) * 50 ); 1 + ( int ) (
Math.random( ) * 50 );
9: To draw a single line from (0, 15) to (20, 25), call the
method _________ of the Graphics class in the
paintComponent method.
a.drawLine( 0, 15, 20, 25 );
b.drawString( "single line", 0, 15 );
c.drawLine( 0, 15, 20, 10 );
d.drawLine( 15, 0, 25, 20 );
10: In the Java graphics system, coordinate units are
measured in ________.
a.dots
b.pixels
c.points
d.inches
11: Which is a correct way to invoke the static method sqrt of
the Math class?
a.sqrt( 900 );.
b.math.sqrt( 900 );.
c.Math.sqrt( 900 );.
d.Math Math(); math.sqrt( 900 );.
12: When an object is concatenated with a String
a.a compilation error occurs.
b.a runtime error occurs.
c.the object’s toString method is implicitly called to obtain the
String representation of the object.
d.the object’s class name is used.
13: What do the following statements do?
double array[];
double[ 14 ];
a. Creates a double array containing 13 elements.
b.Creates a double array containing 14 elements.
4. c. Creates a double array containing 15 elements.
d. Declares but does not create a double array.
14: Consider the class below:
public class Test
{
public static void main( String args[] )
{
int a[];
int[ 10 ];
for ( int ; i <a.length; i++ )
a[ i ] = i + 1 * 2;
int ;
for ( int ; i <a.length; i++ )
result += a[ i ];
System.out.printf( "Result is: %dn", result );
} // end main
} // end class Test
The output of this Java program will be
a. Result is: 62
b. Result is: 64
c. Result is: 65
d. Result is: 67
15: Which method call converts the value in
variable stringVariable to an integer?
a. Convert.toInt( stringVariable )
b. Convert.parseInt( stringVariable )
c. Integer.parseInt( stringVariable )
d.Integer.toInt( stringVariable )