Java

If the Java class TryMe.class is run using the following command: c:> java TryMe one two three What would be the contents of args[1] in the main program.

"two"

The Java Virtual Machine runs code contained in --?-- files.

.class

What is the extension of a file produced from source code by the Java compiler?

.class

In the Java programming language, all source code is first written in plain text files ending with what extension?

.java

If the Java class TryMe.class is run using the following command: c:> java TryMe 1 2 3 What would be output of the following statements in the main method:

123

Characters, by default, are represented in Java using

16-bit Unicode

The largest possible signed positive integer(int) in Java is

2^31 - 1

If the Java class TryMe.class is run using the following command: c:> java TryMe one two three What is the length of the array args[] in the main program?

3

If the array myArray is declared as int[][] myArray = {{2,3,4,5},{3,4,5,6},{4,5,6,7}} What is the value of myArray.length?

3

If the array myArray is declared as int[][] myArray = {{2,3},{3,4},{4,5}} How many rows and columns does it have?

3 rows, 2 columns

Consider the following statement int a [ ] [ ] = { {1,2}, {3,4,5,6}, {7,8,9,0} } The length of a is --?-- and the length of a[2] is --?--

3;4

If the array myArray is declared as int[][] myArray = {{2,3},{3,4,5,6},{4,5,6}} What is the value of myArray[1].length

4

If the array myArray is declared as int[][] myArray = {{2,3},{3,4},{4,5}} What is the value of myArray[1][1]?

4

What will the output of this program segment: int p [ ] = {2,4,6,8} System.out.println(p [ 2 ] );

6

What is the output of the following code: public class ArrayTest { public static void main(String[ ] args) { int [ ] numbers = {3,6,9,12,15}; doSomething(numbers,3); for (int k=0; k < numbers.length; k++) System.out.print(numbers [k] + " "); } public static void doSomething ( int [ ] n, int i) { for (int j = 0; j < n.length; j++) n [ j ] += I; }

6 9 12 15 18

A menu listener implements the interface

ActionListener

What is the correct command to compile the program HelloWorld.java?

C:>javac HelloWorld.java

Class RunTimeException extends from class

Class Exception

Variables that should not be changed should be declared using the modifier

Final

If a Java class is declared as public class HelloWorld { then the name of the file it is saved in must be

HelloWorld.java

The statement pet1 = new Cat("tabby") is an example of

Instantiating an Object

A --?-- contains a --?-- which contains a --?--.

JMenuBar; JMenu; JMenuItem

Exceptions in Java are

Objects

Which is the correct way to instantiate a new TextFileInput object?

TextFileInput tfi = new TextFileInput("myFile.txt");

What are the two main components of the Java language?

The Java Virtual Machine (JVM) and the Application ProgrammingInterface (API)

What will be the output of the following program? public class Question24 { public static void main (String [ ] args) { String items [ ] = { "2468", "good bye", "1357"}; for (int i=0; I <= items.length; i++) try{ System.out.println("The answer is: " + Integer.parseInt(items[ i ] ); } catch (NumberFormatException nfe) { System.out.println("Too bad! " + items[ i ] ); } catch (ArrayIndexOutOfBoundsException aob) { System.out.println("Better luck next time."); } catch (Exception e) { System.out.println("Oh no!"); } } }

The answer is: 2468 Too bad! good bye The answer is: 1357 Better luck next time.

What will be the result of the following statement: int i = Integer.parseInt("45");

The variable i will get the integer value 45.

Java is great language.

True

What would be an appropriate Regular Expression to match a telephone number?

\d{3}-\d{3}-\d{4}

Consider the following segment of Java code. What will be the output? String cat = "Cat"; System.out.println(cat.charAt(1)); changeCat(cat); System.out.println(cat.charAt(1)); ----------------------------------- public static void changeCat(String dog) { dog = "Cut"; }

a a

Static variables belong to

a class;

What is printed when the main program run public class A { private int a=0; protected int b=0; public int c=0; public A ( int z) { a=z; b=z+1; System.out.println("a is: " + a + b is: " + b); } } public class B extends A { public B (int q) { super(q); } } Main program: r = 2; A aaa = new A(r); B bbb = new B(r+2);

a is: 2 b is: 3 a is: 4 b is: 5

The Java Application Programming Interface (API) is

a large collection of ready-made software components.

A platform is the hardware or software environment in which a program runs.Most platforms can be described as a combination of the operating system andunderlying hardware. The Java platform diff ers from most other platforms inthat it's

a software-only platform

A method that cannot handle an exception is called

an exception propagator

An object is

an instance of a Class which has specific properties

instance variable belong to

an object

If the class equalStrings.class is run using c:> java equalStrings cat dog cat rat dog Which of the following statements will be true?

args[0].equals(args[2])

Java .class fi les must be run by the

ava Virtual Machine (JVM)

What are the contents of a .class fi le in Java?

bytecodes

What is the correct command to run the class HelloWorld.class?

c:>java HelloWorld

The following declaration is for a node in a simple linked list. Choose the letter of the correct code from the table on the right for each question to complete the declaration. public <13> ListNode { Object data; ListNode<14>; public ListNode (object myData) { data = <15>; next = null; }

class, next, myData

The variable b is accessible to public class A { private int a=0; protected int b=0; public int c=0; public A ( int z) { a=z; b=z+1; System.out.println("a is: " + a + b is: " + b); } } public class B extends A { public B (int q) { super(q); } } Main program: r = 2; A aaa = new A(r); B bbb = new B(r+2);

classes A and B

The methods A and B are called public class A { private int a=0; protected int b=0; public int c=0; public A ( int z) { a=z; b=z+1; System.out.println("a is: " + a + b is: " + b); } } public class B extends A { public B (int q) { super(q); } } Main program: r = 2; A aaa = new A(r); B bbb = new B(r+2);

constructors

The purpose of a BufferedReader object is to o

deliver one line of the input file at a time

If the array myArray is declared as int[][] myArray = new int[3][4]; Which of the following loops will set all the cells of the array equal to 10? for (int i=0; i<myArray.length(); i++) for (int j=0; j<myArray[i].length()) myArray[i][j] = 10; for (int i=0; i<myArray.length; i++) for (int j=0; j<myArray[i].length) myArray[i][j] = 10; for (int i=0; i<myArray[i].length; i++) for (int j=0; j<myArray[j].length) myArray[i][j] = 10; for (int i=0; i<myArray.length; i++) for (int j=0; j<myArray.length) myArray[i][j] = 10;

for (int i=0; i<myArray[i].length; i++) for (int j=0; j<myArray[j].length) myArray[i][j] = 10;

A process that is in the RUN state

has control of the CPU

A hash map may be implemented using a

indexed array

If the Java class TryMe.class is run using the following command: c:> java TryMe one 2 three Which of the following statements will cause an error?

int i = Integer.parseInt(args[0]);

A process that is in the READY state

is waiting for a turn on the CPU

Hash maps and Tree maps contain a sequence of

key/value pairs

What is the name of the method that is run fi rst when a Java application islaunched?

main

A recursive definition of an array being in sorted order is: If the first two elements are in order the rest of the array is sorted, then the entire array is sorted. Select the missing parts of the following algorithm to complete the code. public static boolean isSorted (int myArray [ ], int i) { if ( i == myArray.length-1) return true; if(myArray [ i ] < <34>) return isSorted(myArray, <35>); else return false; }

myArray[ i+1 ] i+1

The following code is intended to add a new node to the beginning of a linked list (with dummy head node), declared as follows. For each question choose the best answer to complete the code. private ListNode first; private ListNode last; private int length; public prepend (Object myData) { ListNode n = new ListNode(<16>); n.next = <17>; first.next = n; length++; if(last == first) <18> = n; } //prepend

myData first.next last

What do GUI's do while they are waiting for an action event?

nothing

If the Java class TryMe.class is run using the following command: c:> java TryMe one two three What would be the output of the following statement in the main method:

onetwothree

If the Java class TryMe.class is run using the following command: c:> java TryMe one two three What would be the output of the following statement in the main method: for (int i=0; i<args.length;

owr

Assertions are used during --?-- and exceptions are used during --?--.

program development; program execution for users

What is the correct signature of the main method?

public static void main(String[] args)

Which of the following methods is contained in the class TextFileInput? readLine() charAt() parseShort() new TextFileInput(String s)

readLine()

A tree map may be implemented using a

red-black tree

In Java, object parameters are passed by

reference

In Model/View/Controller the controller is

responsible for updating the data

Which of the following is not a Java Development Tool? javac - the Java compiler javadoc - the Java Documentation producer java - the Java Launcher the JVM

the JVM

In Model/View/Controller, the model is

the data to be displayed

Menu handlers can pass a reference to their own GUI by using the --?—operator.

this

Suppose in the following program segment, x is supposed to be less than 5. Which of the following is the correct code for <statement A> so that an exception is thrown if that is not the case: if (! x<5) <statement A>

throw new IllegalArgumentException("x must be < 5");

If you want items to come out in sorted order it's best to use a

tree map

In Java, primitives are passed by

value

In Java, primitive parameters are passed by --?-- and object parameters are passed by --?--.

value; reference