Question
Bank
Unit
- I
2
Marks
- Define Object oriented Programming?
i.)
Object oriented programming is a programming methodology that uses ‘objects’
to design applications and computer programs.
ii.)
Since Java is an object oriented programming language it has following
features:
·
Reusability of Code
·
Emphasis on data rather than procedure
·
Data is hidden and cannot be accessed by external functions
·
Objects can communicate with each other through functions
·
New data and functions can be easily added
- What is Java ?
JAVA- Just
Another Virtual Architecture
Java is a simple and yet powerful object oriented programming language and it
is in many respects similar to C++. Java was given birth at Sun Microsystems,
Inc. in 1991. Java was conceived by James Gosling, Patrick Naughton, Chris
Warth, Ed Frank, and Mike Sheridan at Sun Microsystems, Inc in 23 March 1995.
It was developed to provide a platform-independent programming language.
- What is the Java
Virtual Machine? What is its role?
Java was designed with a concept of
‘write once and run everywhere’. At the heart of the Java platform lies in the
Java Virtual Machine, or JVM. Most programming languages compile source code
directly into machine code, suitable for execution on particular microprocessor
architecture. The difference with Java is that it uses bytecode - a special
type of machine code.
- When
to use pipe stream for performing I/O operation? Or What is meant by Piped Streams?
Pipes are used to channel the output from one
program (or thread) into the input of another.
- What
is the storage structures used to represent byte code?
Various systems may often be stored in separate
files, similar to object module,
but distinguishably during execution. The byte code gets its name from a set of instructions called
one-byte opcodes.
- What
is the use of thread?
Thread
are used to provide multi-programming environment.
- Give
the syntax and use of any four classes in swing?
JFrame
classes
JFrame frame = new JFrame("JFrame Source Demo");
frame.addWindowListener(new WindowAdapter(){public void
windowClosing(WindowEvent e) { System.exit(0);}});
- Write a java program to read an
integer and to display the same.
import java.io.*;
import
java.lang.*;
public class
BinaryToDecimal{
public
static void main(String[] args) throws IOException{
BufferedReader bf = new
BufferedReader(new
InputStreamReader(System.in));
System.out.println("Enter
the Binary value:");
String binaryNumber =
bf.readLine();
int
decimalNumber = Integer.parseInt(binaryNumber,2);
System.out.println("Binary
number converted to decimal number");
System.out.println("Decimal
number is : " + decimalNumber);
}
}
- What are the benefits in using
swings compared to awt?
1. Pluggable Look and Feel
2. Swing is more lightweight than AWT
3. Components can be bound to keyboard events to react to keystrokes.
4. Built on the MVC model
5. Better support for multi-threading
- How
are the strings transferred between native methods in Java?
The
class JNIString to transfer strings between Java and the native code.
- Write
a Java statement that tests if a thread is alive.
class
RThread implements Runnable
{
Thread t;
RThread (String msg)
{
t = new Thread (this, msg);
t.start();
}
public void run()
{
for (int i=0;i<5;i++)
{
try
{
System.out.println(Thread.currentThread()+" : "+i);
t.sleep(100);
}
catch(InterruptedException e){}
}
}
}
class
T
{
public static void main(String arg[])
{
RThread r1 = new
RThread("First");
RThread r2 = new RThread("Second");
RThread r3 = new
RThread("Third");
System.out.println("Alive
Status of Thread1 :" +r1.t.isAlive());
System.out.println("Alive
Status of Thread2 :" +r2.t.isAlive());
System.out.println("Alive
Status of Thread3 :" +r3.t.isAlive());
}
}
- Define
the term Byte code in Java. (or) State the purpose of Byte code.
Byte code is a term which assigned to various forms
of instructions framed for efficient execution of a java
program, also for the implementation of compilation into machine code.
- What is Reflection?
Reflection is a powerful approach to analyses the
class at runtime. Reflection uses special kind of java class: Class. The object
of the Class type can hold all the information of the class and have getter
methods to extract this information.
- What is Java I/O?
The Java Input/Output (I/O) is a part ofjava.io package.
The java.io package contains a relatively large number of
classes that support input and output operations.
- What
are the two ways to create a simple Thread?
Java defines two ways in
which this can be accomplished:
·
You can implement the Runnable interface.
·
You can extend the Thread class, itself.
- Difference between the Applet and Swing.
1) Swing is light weight component
while applet is heavy weight component.
2) Applet has no main method, but
swings have.
3) Swing have look and feel while
Applet Does not provide this facility
4) Swing uses for standalone
Applications while Applet needs HTML code for Run the
Applet
5)
Swing has its own Layout while Applet uses Awt Layout.
17. What is Swings in java?
i.)
A part of The JFC (Java Foundation Classes)
ii.) Swing Java consists
of
·
Look and feel
·
Accessibility
·
Java 2D
·
Drag and Drop, etc
18. What is Java
Streaming?
Java streaming is nothing more
than a flow of data. There are input streams that direct data from the outside
world from the keyboard, or a file for instance, into the computer; and output
streams that direct data toward output devices such as the computer screen or a
file.
19. What are
Byte streams?
Byte streams provide a
convenient means for handling input and output of bytes. Byte streams are used
for example when reading or writing binary data.
20. What are
Character streams?
Character streams, provide a
convenient means for handling input and output of characters. They use Unicode,
and therefore, can be internationalized.
21. List some
Byte Stream supported classes.
·
BufferedInputStream
·
BufferedOutputStream
·
ByteArrayInputStream
·
ByteArrayOutputStream
·
DataInputStream
·
DataOutputStream
22. List some Character Stream supported
classes.
·
BufferedReader
·
BufferedWriter
·
CharArrayReader
·
CharArrayWriter
·
FileReader
·
FileWriter
23. Write note on FileInputStream class.
The
FileInputStream class creates an InputStream that you can use to read bytes
from a file. Its two most
common constructors are
FileInputStream(String filepath)
FileInputStream(File fileobj)
24. Write note on
FileOutputStream class.
FileOutputStream creates an OutputStream that you can use to write bytes
to a file. Its most commonly used
constructors are
FileOutputStream(String filepath)
FileOutputStream(File
fileobj)
FileOutputStream(String filepath,
Boolean append)
They can throw an IOException or a
SecurityException.
25. What is the use of the class
“ByteArrayInputStream”?
ByteArrayInputStream is
an implementation of an input stream that uses a byte array as the source. This class as
two constructors, each of which
requires a byte array to provide the data source:
ByteArrayInputStream(byte array[])
ByteArrayInputStream(byte array[], int start, int numbytes)
26. What is an Event?
An event is an object that
describes a state change in a source. It can be generated as a consequence of a
person
interacting with the elements in a
graphical user interface. Some of the
activities that cause events to be generated are
pressing a button, entering a character
via the keyboard, selecting an item in a list and clicking the mouse.
27. What is an Event Listener?
A Listener is an object
that is notified when an event occurs. Only the types of events, which are
registered with an
event listener will be received
by that listener.
28. When does an ActionEvent generate?
An ActionEvent is
generated when a button is pressed, a list-item is double-clicked, or a menu item is selected.
You can obtain the command
name for the invoking ActionEvent object by using the getActionMethod() method.
String
getActionCommand()
29. When is ComponentEvent generated?
A ComponentEvent is
generated when the size, position, or visibility of a component is changed. The
getComponent() method of
ComponentEvent returns the component that generated the event.
30. Define Multithread Programming.
A multithreaded program
contains two or more parts that can run concurrently. Each part of such program is
called a thread, and each thread
defines a separate path of execution. Thus, multithreading is a specialized
form of
multitasking.
31. What is Synchronization?
When two or more threads
need access to a shared resource, they need some way to ensure that the
resource will be
used by only one thread at a time.
The process by which this is achieved is called synchronization.
32. In multithreading, When does a deadlock
situation occur?
Deadlock situation
occurs, when two threads have a circular dependency on a pair of synchronized objects.
33. What is the need of Thread Priorities?
Thread priorities are used
by the thread scheduler to decide when each thread be allowed to run.
Higher-priority
threads get more CPU time than
lower-priority threads. To set a thread’s priority, use the setPriority()
method, which is
a member of Thread.
34. What is the use of Layout Managers in
Swing?
The Layout Managers are used to place
the components in a predefined manner relative to each other.
The
layout
manager puts the components in a queue and arranges them one after the other rather than placing the
components
according to the coordinates. This helps
in achieving platform independence.
35. List some Layout Managers supported by
Swing.
The most common Layout Managers supported
by Swing are
·
Box Layout
·
Grid Layout
·
GridBag Layout
·
Border Layout
16
Marks
- Explain
Byte stream and Data stream with their applicability.(8)
Definition
of Byte stream and Data stream (3),
Using
of Byte stream and Data Input and Output stream (3),
Example
program (2),
- How
to extract the methods and constructors defined in a class using
reflection in Java. (8)
(or) What is
reflection? Explain its use. (8) (or) Explain Dynamic reflexive classes. (8)
Definition
of Reflection (3)
Uses
of Reflection (3)
Example
program (2)
- Explain
the implementation of thread synchronization in Java.(10)
Definition
of Multi-Threading (1)
List
out the Multi-Threading Concepts (1)
Thread
Synchronization using Synchronized Block With Example (4)
Thread
Synchronization using Synchronized Method With Example (4)
- Write
a Java program for Reading and Writing the data from a file. (8)
import
java.io.*;
class
ReadWriteData
{
public static void main(String
args[])
{
int
ch=0;
int[]
numbers = {12,8,13,29,50};
try
{
System.out.println("1.
Write Data");
System.out.println("2.
Read Data");
System.out.println("Enter
your choice ");
BufferedReader
br=new BufferedReader(new
InputStreamReader(System.in));
ch=Integer.parseInt(br.readLine());
switch(ch)
{
case
1:
DataOutputStream
out =new DataOutputStream
(new
FileOutputStream("datafile.txt"));
for
(int i=0; i < numbers.length; i++)
{
out.writeInt(numbers[i]);
}
System.out.print("write
successfully");
out.close();
case
2:
DataInputStream
in =new DataInputStream
(new FileInputStream("datafile.txt"));
while
(true)
{
System.out.print(in.readInt());
}
default:
System.out.println("Invalid
choice");
}
}
catch(IOException
e)
{
System.out.println(e.getMessage());
}
}
}
- Write a
program in Java Applet for
dynamically changing the color of Text using Multithreading. (8)
import
java.applet.*;
import
java.awt.*;
import
java.awt.event.*;
public
class FontAnimation extends Applet implements ActionListener
{
TextField text=new
TextField(20);
TextField red=new TextField(20);
TextField gr=new TextField(20);
TextField blue=new
TextField(20);
Button b1=new
Button("Apply");
String str="Hello";
int size=10;
Font f;
boolean inc=true;
int r,g,b;
Color fcolor;
public void init()
{
add(new
Label("Enter Text to animate here"));
add(text);
add(new
Label("Enter value for Red Color here"));
add(red);
red.setText("0");
add(new
Label("Enter value for Green Color here"));
add(gr);
gr.setText("0");
add(new Label("Enter
value for Blue Color here"));
add(blue);
blue.setText("0");
add(b1);
b1.addActionListener(this);
}
public void
actionPerformed(ActionEvent e)
{
if(e.getSource()==b1)
{
str=text.getText();
if(str=="") str="Hello";
r=Integer.parseInt(red.getText());
g=Integer.parseInt(gr.getText());
b=Integer.parseInt(blue.getText());
fcolor=new
Color(r,g,b);
repaint();
}
}
public void paint(Graphics g)
{
f=new
Font("Arial",Font.BOLD,size);
g.setFont(f);
g.setColor(fcolor);
g.drawString(str,50,200);
try
{
Thread.sleep(500);
}
catch(Exception
e)
{
System.out.println(e.getMessage());
}
if(inc==true)
{
size+=10;
if(size==100)
inc=false;
}
else
{
size-=10;
if(size==10)
inc=true;
}
repaint();
}
}
- Develop
Java swing code for creating student Bio-data form. (8)
import
javax.swing.*;
import
java.awt.*;
public
class BioData extends JFrame
{
int i;
JLabel
lbl1,lbl2,lbl3,lbl4,lbl5,lbl6,lbl7,lbl8,lbl9;
JTextField txt1,txt2;
JTextArea ta1;
JCheckBox c1,c2,c3;
JRadioButton r1,r2;
JTable t1;
JList l1;
JButton b1,b2;
JComboBox date,month,year;
String[]
colHeads={"Year","Percenatage","School/Degree"};
Object[][]
data={{"","","S.S.L.C"},{"","","H.S.C"},{"","","Bsc"},{"","","MCA"}};
String[]
listData={"English","Tamil","Telegu"};
String[] mon=
{"Jan","Feb","March","Apr","May","June","July","Aug","Sep","Oct","Nov","Dec"};
public BioData(String t)
{
super(t);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container
cp=getContentPane();
cp.setLayout(new
BorderLayout());
JPanel jp1=new
JPanel();
JPanel jp2=new
JPanel();
JPanel jp3=new
JPanel();
jp1.setLayout(new
GridBagLayout());
GridBagConstraints
gbc=new GridBagConstraints();
lbl1=new JLabel("BIO-DATA");
jp3.add(lbl1);
lbl2=new
JLabel("Name");
lbl3=new
JLabel("Address");
lbl4=new
JLabel("Tel No");
lbl5=new
JLabel("Gender");
lbl6=new
JLabel("Hobbies");
lbl7=new
JLabel("Educational Qualification");
lbl8=new
JLabel("Language Known");
lbl9=new
JLabel("Date Of Birth");
date=new
JComboBox();
for(i=1;i<=31;i++)
{
String
str=Integer.toString(i);
date.addItem((Object)str);
}
month=new
JComboBox(mon);
year=new
JComboBox();
for(i=1980;i<=2020;i++)
{
String
str=Integer.toString(i);
year.addItem((Object)str);
}
txt1=new
JTextField(25);
txt2=new
JTextField(25);
ta1=new
JTextArea();
JScrollPane
s1=new JScrollPane(ta1,
ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
b1=new
JButton("SUBMIT");
b2=new
JButton("RESET");
c1=new
JCheckBox("Reading");
c2=new
JCheckBox("Music");
c3=new
JCheckBox("Movies");
ButtonGroup
b=new ButtonGroup();
r1=new
JRadioButton("Male");
r2=new
JRadioButton("Female");
b.add(r1);
b.add(r2);
t1=new
JTable(data,colHeads);
JScrollPane
s=new JScrollPane(t1,
ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
l1=new
JList(listData);
l1.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
gbc.insets=new
Insets(10,10,10,10);
gbc.weightx=1.0;
gbc.weighty=1.0;
gbc.fill=GridBagConstraints.HORIZONTAL;
gbc.gridx=0;
gbc.gridy=0;
jp1.add(lbl2,gbc);
gbc.gridx=1;
gbc.gridy=0;
jp1.add(txt1,gbc);
gbc.gridx=0;
gbc.gridy=1;
gbc.gridheight=2;
jp1.add(lbl3,gbc);
gbc.gridx=1;
gbc.gridy=1;
gbc.gridheight=2;
gbc.weighty=1.0;
gbc.fill=GridBagConstraints.BOTH;
jp1.add(s1,gbc);
gbc.gridx=0;
gbc.gridy=3;
gbc.gridheight=1;
gbc.weighty=0.0;
jp1.add(lbl4,gbc);
gbc.gridx=1;
gbc.gridy=3;
jp1.add(txt2,gbc);
gbc.gridx=0;
gbc.gridy=4;
jp1.add(lbl5,gbc);
gbc.gridx=1;
gbc.gridy=4;
jp1.add(r1,gbc);
gbc.gridx=2;
gbc.gridy=4;
jp1.add(r2,gbc);
gbc.gridx=0;
gbc.gridy=5;
jp1.add(lbl9,gbc);
gbc.gridx=1;
gbc.gridy=5;
jp1.add(date,gbc);
gbc.gridx=2;
gbc.gridy=5;
jp1.add(month,gbc);
gbc.gridx=3;
gbc.gridy=5;
jp1.add(year,gbc);
gbc.gridx=0;
gbc.gridy=6;
jp1.add(lbl6,gbc);
gbc.gridx=1;
gbc.gridy=6;
jp1.add(c1,gbc);
gbc.gridx=2;
gbc.gridy=6;
jp1.add(c2,gbc);
gbc.gridx=3;
gbc.gridy=6;
jp1.add(c3,gbc);
gbc.gridx=0;
gbc.gridy=7;
jp1.add(lbl7,gbc);
gbc.gridx=1;
gbc.gridy=7;
gbc.weighty=1.0;
gbc.gridwidth=gbc.REMAINDER;
jp1.add(s,gbc);
gbc.gridx=0;
gbc.gridy=8;
gbc.weighty=0.0;
jp1.add(lbl8,gbc);
gbc.gridx=1;
gbc.gridy=8;
gbc.gridwidth=gbc.REMAINDER;
jp1.add(l1,gbc);
jp2.add(b1);
jp2.add(b2);
cp.add(jp3,BorderLayout.NORTH);
cp.add(jp1,BorderLayout.CENTER);
cp.add(jp2,BorderLayout.SOUTH);
setSize(500,630);
setVisible(true);
}
public static void main(String
args[])
{
new
BioData("BIODATA");
}
}
- Write a java program to read a text
file and to count the number of words and sentences. (8)
import
java.io.*;
import
java.util.*;
class
Tip
{
public
static void main(String [] args) throws Exception
{
FileInputStream
is = new FileInputStream( "tip.txt" );
Scanner scan =
new Scanner( is );
String
tempString = "";
int
lines = 0;
int
words = 0;
Vector<Integer>
wordLength = new Vector<Integer>();
while(scan.hasNextLine()
== true)
{
tempString = scan.nextLine();
lines++;
}
is.close();
is
= new FileInputStream( "tip.txt" );
scan
= new Scanner( is );
while(scan.hasNext()
== true)
{
tempString = scan.next();
wordLength.add(tempString.length());
words++;
}
System.out.println("Lines
: " + lines);
System.out.println("Words
: " + words);
is.close();
}
}
- Explain the life cycle of thread. (8)
Definition
of Thread (3)
Several
Stages of Thread (New, Runnable, Waiting, Terminated) (3)
Thread
Life Cycle Diagram (2)
- What is JNI? Explain its usage. (10)
Definition
of JNI (2)
Role
of the JNI (4)
Implication
of using JNI (4)
- Briefly
explain the Java i/o stream class hierarchy. (10)
Java
I/O streams (2)
Input
Stream class Hierarchy and explanation of any one class with example (4)
Output
Stream class Hierarchy and explanation of any one class with example (4)
- Illustrate
the use of Pipes for communication between the threads with suitable java
program. (6)
Definition
of pipes (2)
PipeReader
and PipeWriter Class (2)
Example
(2)
- Explain
Inter-thread communication in java with an example. (8)
Definition
of Thread, Multithreading and Inter-thread Communication (3)
Explanation of
few methods of Inter-process communication (wait(), notify(), notifyAll()) (3)
Example
(2)
- What
is swing? Explain its features. (8)
Swing
Model/view design (2)
Swing
Class hierarchy and explanation of any two swing component classes (3)
Example
(3)
- Explain
JVM in detail. (6)
Explanation
of Java, JRE, Java API classes, and JVM (3)
Structure
of JVM. (3)
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