Java Lab Manual

naveensagayaselvaraj@gmail.com NAVEEN SAGAYASELVARAJ
JAVA PROGRAMMING
MANUAL
Prepared by
Mr. NAVEEN SAGAYASELVARAJ
Lecturer
CSC Computer Education
Krishnagiri
Ms. MANGAIYARKKARASI V
Lecturer
CSC Computer Education
Gopichettipalayam

I
S.NO. CONTENT PAGE NO.
1 INTRODUCTION 1
2 PROGRAMMING CONSTRUCTS &
CASTING AND TYPE CONVERSION
4
3 ARRAYS 11
4 STRING CLASS 15
5 COSTRUCTOR 20
6 INHERITANCE AND INTERFACE 23
7 I/O STREAM CLASSES 27
8 APPLETS AND SWINGS 39
9 EVENT-HANDLING 49
10 MULTITHREADING 54
11 NETWORKING-I 59
12 NETWORKING-II 68

1
1 INTRODUCTION
OBJECTIVE:
Basic Programming using class and objects.
OVERVIEW:
Classes and Objects:
The fundamental programming unit of the Java programming language is the class. Classes provide
the structure for objects and the mechanisms to manufacture objects from a class definition. Classes define
methods: collections of executable code that are the focus of computation and that manipulate the data stored
in objects. Methods provide the behavior of the objects of a class.
Syntax:
For Class definition:
class class_name
{
Datatype variable_name; //Data_Memebers
Returntype method_name(parameters) //Member_Function
{
-------------;
}
Pubic static void main(String arg[ ])
{
//Main Method block
}
}
For Object creation:
class_name object_name = new class_name( );
objectname.variable_name;
objectname.methodname( );
To access data_members and
member_function of the class

2
Sample coding:
/**
*
* @author NaveenSagayaelvaRaj
*/
public class First_Program
{
private int first_num = 5;
private int second_num = 6;
public void add()
{
int answer;
answer = first_num+second_num;
System.out.println("Answer: "+answer);
}
public static void main(String arg[])
{
First_Program obj=new First_Program();
obj.add();
}
}
Output:
run:
Answer: 11
BUILD SUCCESSFUL (total time: 1 second)

3
PRE LAB EXERCISE
Define a class sample with the following specification
Public member function of class sample
Display() Function to Display “Hello!! World”
IN LAB EXERCISE
Define a class student with the following specification
Private members of class student
Roll_no int
Phy,che& mathsdouble
Total double
Average int
Cal_Total() a function to calculate Total with double return type
Cal_Avg() a function to calculate Average with int return type
Public member function of class student
Takedata() Function to accept values for Roll_no, Phy,che, maths,
invoke Cal_total() to calculate total and invoke Cal_Avg() to calculate average.
Showdata() Function to display all the data members.
POST LAB EXERCISE
Define a class BOOK with the following specifications :
Private members of the class BOOK are
BOOK NO integer type
PRICE double (price per copy)
TOTAL_COST() A function to calculate the total cost for N number of
copies where N is passed to the function as argument.
Public members of the class BOOK are
INPUT() function to read BOOK_NO., PRICE
PURCHASE() function to ask the user to input the number of copies to be
purchased. It invokes TOTAL_COST() and prints the total
cost to be paid by the user.
Result:

4
2 PROGRAMMING CONSTRUCTS & CASTING
AND TYPE CONVERSION
OBJECTIVE:
Programming using constructs, looping, casing and type conversions.
OVERVIEW:
SELECTION CONTROL STRUCTURE:
A selection control structure, allows a program to select between two or more alternative paths of
execution.
 if Statement:
if statement is the most basic selection control structure.
Syntax:
if(boolean expression)
{
Statement;
}
 if else Statement:
Syntax:
{
Statement;
}
else
{
Statement;
}

5
 else if Statement:
Syntax:
{
Statement;
}
else if(boolean expression)
{
Statement;
}
else
{
Statement;
}
 Nested if:
Syntax:
{
Statement;
{
Statement;
}
}
else
{
Statement;
}
 Switch Statement:
It’s a multiway branching statement. It is based on value on expression.

6
Syntax:
switch(ch)
{
case 1:
Statement;
break;
case 2:
Statement;
break;
.
.
.
.
case n:
Statement;
break;
default:
Statement;
break;
}
LOPPING STATEMENTS:
Looping statement causes a section of statements in the program to be executed a certain number of
times. The repetition remains until the condition is true. If the condition false loop ends, and the control
structure passes to the next statement.
 for Loop:
Syntax:
for(Initialization ; boolean expression ; Iteration)
{
Statement:
}
 Enhanced For Loop:
This type of for loop allows iterating through an array without creating an iterator. And do not
need to maintain index of each element.

7
Syntax:
for(declaration:expression)
{
Statement:
}
 while Loop
Syntax:
while(boolean expression)
{
Statement:
}
 do while Loop:
Syntax:
do
{
Statement:
} while(boolean expression);
CASTING AND CONVERSION:
Casting allow converting a variable of one datatype to another.
Types of conversion:
1. Implicit conversion- Automatic conversion take place of one datatype to another.
Example int to long automatic conversion.
2. Explicit conversion- We force to convert one datatype to another
Syntax
(type) value;
Example:
char ch = ’A’;
int Asci=(int)ch; //Explicit conversion take place
Example:

8
int Asci = 65;
char ch=(char)ch; //Explicit conversion take place
Sample coding:
/**
*
* @author NaveenSagayaselvaRaj
*/
public class Second_Program {
{
System.out.println("**Find whether the given element is Alphabet or a
Numberic**n");
char ch='H';
int Asci=(int)ch;
if((Asci>=65 && Asci<=90) || (Asci>=97 && Asci<=122))
{
System.out.println(ch+" is a Alphabet ");
}
else if((Asci>=48 && Asci<=57))
{
System.out.println(ch+" is a Numeric ");
}
}
Output:
run:
**Find whether the given element is Alphabet or a Numeric**
H is a Alphabet
BUILD SUCCESSFUL (total time: 1 second)

9
Sample coding:
/**
*
*/
import java.util.Scanner;
public class Third_Program {
public static void main(String args[])
{
int n, num = 1, c, d;
Scanner in = new Scanner(System.in);
System.out.println("Enter the number of rows of floyd's triangle you want");
n = in.nextInt();
System.out.println("**Floyd's triangle**");
for ( c = 1 ; c <= n ; c++ )
{
for ( d = 1 ; d <= c ; d++ )
{
System.out.print(num+" ");
num++;
}
System.out.println();
}
}
}
Output:
run:
Enter the number of rows of floyd's triangle you want
8
**Floyd's triangle**
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
BUILD SUCCESSFUL (total time: 5 seconds)

10
PRE LAB EXERCISE
a. Write a Java program to find Asci value of given char
b. Write a Java program to print output as follows,
1
2 2
3 3 3
4 4 4 4
5 5 5 5 5
IN LAB EXERCISE
a. Write a Java program to change Upper case alphabet to Lower case alphabet
b. Write a Java program to print Pyramid
POST LAB EXERCISE
a. Write Java program to convert the following,
I/P Enter a character: 3
O/P Converted into int: 3
b. Write a Java program to print Diamond
Result:

11
3 ARRAYS
OBJECTIVE:
Programming using arrays.
OVERVIEW:
Arrays:
An Array is a contiguous block of memory location referred by a common name. The length of the
array is fixed at the time of creation.
Steps to create an Array:
1. Declare an Array
2. New operator to allocate memory to an Array
Types of Arrays:
 One Dimensional Array
 Multi-Dimensional Array
Syntax:
For One Dimensional Array:
1. Declare an Array
Datatype Array_Name [ ];
Array_Name[ ] = new Datatype[boundary condition ];
For Multi-Dimensional Array:
1. Declare an Array
Datatype Array_Name [ ] [ ];

12
Array_Name[ ] = new Datatype[boundary condition ] [boundary condition
];
Sample coding:
/**
*
*/
public class Fourth_Program {
{
int array[]=new int[10];
int sum=0;
Scanner in=new Scanner(System.in);
System.out.println("Enter 10 elements: ");
for(int i=0;i<10;i++)
{
array[i]=in.nextInt();
}
{
sum+=array[i];
}
System.out.print("Sum of the elements of an Array: "+sum);
}
}
Output:
run:
Enter 10 elements:
1 2 3 4 5 6 7 8 9 0
Sum of the elements of an Array: 45

13
Sample coding:
/**
*
*/
public class Fifth_Program {
{
int org_arr[][]=new int[2][2];
int tra_arr[][]=new int[2][2];
System.out.println("***********Transpose of Matrix********");
System.out.println("Enter the elements for 2X2 matrix:");
{
for(int j=0;j<2;j++)
{
org_arr[i][j]=in.nextInt();
}
}
{
{
tra_arr[i][j]=org_arr[j][i];
}
}
{
{
System.out.print(tra_arr[i][j]);
}
}
}
}

14
Output:
run:
***********Transpose of Matrix********
Enter the elements for 2X2 matrix:
1 2
3 4
1 3
2 4
PRE LAB EXERCISE
a. Write a Java program to find product of n elements in an array
b. Write a Java program to find addition of two matrices
IN LAB EXERCISE
a. Write Java program to find whether the given element in the array are positive real number or
negative real number or zero
b. Write a Java program to find a given matrix is diagonal matrix or not
POST LAB EXERCISE
a. Write a Java program for TIC TAC TOE game
Result:

15
4 STRING CLASS
OBJECTIVE:
Detailed study on string class and its methods
OVERVIEW:
String class:
String is the most commonly used class in Java. String is a instance of the class string. They are real
object.
Methods in String class:
S.NO Method Description
1 char charAt(int index) Returns the character at the specified index
2 int compareTo(Object o) Compares this String to another Object.
3
int compareTo(String anotherString)
Compares two strings lexicographically.
4 int compareToIgnoreCase(String str) Compares two strings lexicographically,
ignoring case differences.
5 String concat(String str) Concatenates the specified string to the end of
this string
6 boolean contentEquals(StringBuffer sb) Returns true if and only if this String
represents the same sequence of characters as
the specified StringBuffer.
7 static String copyValueOf(char[] data) Returns a String that represents the character
sequence in the array specified
8 static String copyValueOf(char[] data, int
offset, int count)
Returns a String that represents the character
sequence in the array specified
9 boolean endsWith(String suffix) Tests if this string ends with the specified
suffix
10 boolean equals(Object anObject) Compares this string to the specified object.
11 boolean equalsIgnoreCase(String
anotherString)
Compares this String to another String,
ignoring case considerations.
12 byte getBytes() Encodes this String into a sequence of bytes
using the platform's default charset, storing
the result into a new byte array.
13 byte[] getBytes(String charsetName) Encodes this String into a sequence of bytes
using the named charset, storing the result
into a new byte array.
14 void getChars(int srcBegin, int srcEnd,
char[] dst, int dstBegin)
Copies characters from this string into the
destination character array.
15 int hashCode() Returns a hash code for this string.
16 int indexOf(int ch) Returns the index within this string of the first
occurrence of the specified character.

16
17 int indexOf(int ch, int fromIndex) Returns the index within this string of the first
occurrence of the specified character, starting
the search at the specified index.
18 int indexOf(String str) Returns the index within this string of the first
occurrence of the specified substring.
19 int indexOf(String str, int fromIndex) Returns the index within this string of the first
occurrence of the specified substring, starting
at the specified index
20 String intern() Returns a canonical representation for the
string object.
21 int lastIndexOf(int ch) Returns the index within this string of the last
occurrence of the specified character
22 int lastIndexOf(int ch, int fromIndex) Returns the index within this string of the last
occurrence of the specified character,
searching backward starting at the specified
index.
23 int lastIndexOf(String str) Returns the index within this string of the
rightmost occurrence of the specified
substring.
24 int lastIndexOf(String str, int fromIndex) Returns the index within this string of the last
occurrence of the specified substring,
searching backward starting at the specified
index.
25 int length() Returns the length of this string.
26 boolean matches(String regex) Tells whether or not this string matches the
given regular expression.
27 boolean regionMatches(boolean
ignoreCase, int toffset, String other, int
ooffset, int len)
Tests if two string regions are equal.
28 boolean regionMatches(int toffset, String
other, int ooffset, int len)
Tests if two string regions are equal
29 String replace(char oldChar, char
newChar)
Returns a new string resulting from replacing
all occurrences of oldChar in this string with
newChar.
30 String replaceAll(String regex, String
replacement )
Replaces each substring of this string that
matches the given regular expression with the
given replacement.
31 String replaceFirst(String regex, String
replacement)
Replaces the first substring of this string that
matches the given regular expression with the
given replacement.
32 String[] split(String regex) Splits this string around matches of the given
regular expression.
33 String[] split(String regex, int limit) Splits this string around matches of the given
regular expression.
34 boolean startsWith(String prefix) Tests if this string starts with the specified
prefix.
35 boolean startsWith(String prefix, int
toffset)
Tests if this string starts with the specified
prefix beginning a specified index
36 CharSequence subSequence(int
beginIndex, int endIndex)
Returns a new character sequence that is a
subsequence of this sequence

17
37 String substring(int beginIndex) Returns a new string that is a substring of this
string.
38 String substring(int beginIndex, int
endIndex)
Returns a new string that is a substring of this
string
39 char[] toCharArray() Converts this string to a new character array.
40 String toLowerCase() Converts all of the characters in this String to
lower case using the rules of the default
locale.
41 String toLowerCase(Locale locale) Converts all of the characters in this String to
lower case using the rules of the given Locale.
42 String toString() This object (which is already a string!) is
itself returned.
43 String toUpperCase() Converts all of the characters in this String to
upper case using the rules of the default
locale.
44 String toUpperCase(Locale locale) Converts all of the characters in this String to
upper case using the rules of the given Locale
45 String trim() Returns a copy of the string, with leading and
trailing whitespace omitted.
46 static String valueOf(primitive data type
x)
Returns the string representation of the passed
data type argument

18
Sample coding:
/**
*
*/
public class Sixth_Program {
//Find whether the string is plaindrome or not
{
String str;
System.out.println("Enter the string: ");
str=in.next();
//Reverse the String
String rev = "";
int length=str.length();
for(int i=0;i<length;i++)
{
rev+=str.charAt(length-i-1);
}
if(str.compareTo(rev)==0)
{
System.out.println("Its a Palindrome");
}
else
{
System.out.println("Its a not Palindrome");
}
}
}
Output:
run:
Enter the string:
malayalam
Its a Palindrome

19
PRE LAB EXERCISE
a. Write a program to find length of the given string without using the string class’s method
b. Write a Java program to find number of lower case and number of upper case letters in a string
IN LAB EXERCISE
a. Write a Java program to find whether the given string is palindrome or not without using string
class’s methods
b. Write a Java program to change upper case character to lower case character in a string, vice
versa,.
POST LAB EXERCISE
a. Write Java program to find whether the given string is palindrome or not if the characters of the
strings is interchanged
Eg:
I/P Enter the string: tests
O/P It will became palindrome
Result:

20
5 COSTRUCTOR
OBJECTIVE:
Programming using a special type of member function
OVERVIEW:
Constructor:
Constructor method is a special kind of method which are used to initialize objects.
Characteristic of Constructor:
b. Constructor name same as the class name
c. It should be declared as public
d. It should not have any return type
e. It invoked when an object of class is created, it can't be called explicitly
f. It can be overloaded
Types of Constructor:
1. Default constructor – Constructor without arguments
2. Parameterized constructor – Constructor with arguments
Sample coding:
Default constructor:
/**
*
*/
public class Seventh_Program {
Seventh_Program() {
System.out.println("Constructor method called.");
}
public static void main(String[] args) {
Seventh_Program obj = new Seventh_Program();
}
}

21
Output:
run:
Constructor method called.
Parameterized constructor:
/**
*
*/
public class Eigth_Program {
Eigth_Program(int num) {
System.out.println("Number: "+num);
}
public static void main(String[] args) {
Eigth_Program obj = new Eigth_Program(50);
}
}
Output:
run:
50

22
PRE LAB EXERCISE
*******************************NILL************************************
IN LAB EXERCISE
a. Define a class called fruit with the following attributes :
1. Name of the fruit
2. Single fruit or bunch fruit
3. Price
Define a suitable constructor and display_Fruit() method that displays values of all the attributes.
Write a program that creates 2 objects of fruit class and display their attributes.
POST LAB EXERCISE
*******************************NILL************************************
Result:

23
6 INHERITANCE AND INTERFACE
OBJECTIVE:
Programming using various types of inheritance concept
OVERVIEW:
Inheritance:
Inheritance enable you to reuse the functionality and capabilities of the existing class by extending
a new class from existing class and adding new future to it. In inheritance the class that inherits the data
member and methods from another class is known as subclass. The class from which the subclass inherits is
known as the super class.
Types of Inheritance:
1. Single Level Inheritance
2. Multilevel Inheritance
Single Level Inheritance:
Multilevel Inheritance:
super_class_name
sub_class_name1 sub_class_name2
super_class_name
sub_class_name1
sub_class_name2

24
Syntax:
Single Level Inheritance
class super_class_name
{
//body of the class super_class
}
class sub_class_name1 extends super_class_name
{
//body of the sub_class
}
{
}
Multilevel Inheritance
class super_class_name
{
//body of the class super_class
}
{
}
class sub_class_name2 extends sub_class_name1
{
}
Interface:
There may be cases where we need to inherit the features of more than one class. But Java does
not support multiple inheritance. However, we can simulate multiple inheritance in java by using interface.

25
Syntax:
interface interface_name
{
//interface body
static final data members;
return type public methods(parameters);
}
class sub_class_name extends super_class_name implements interface_name
{
//Defining the method declare in the interface
return type public methods(parameters)
{
//Body of the method
}
}
Sample coding:
public class Nine_Program {
void display()
{
System.out.println("Super_Class");
}
}
public class Tenth_Program extends Nine_Program{
{
Tenth_Program obj=new Tenth_Program();
obj.display();
}
}
run:
Super_Class

26
PRE LAB EXERCISE
*******************************NILL************************************
IN LAB EXERCISE
a. Create a class student and declare variable rollno.
Create function getnumber() and display().
Create another class test which inherit student.
Create function display().
Create another interface sports with variable sport and function putsp().
Create variable total and function putsp(),display().
Create another class result which extends the test and sport.
Create main class main_class and which has the student as object of class result.
POST LAB EXERCISE
*******************************NILL************************************
Result:

27
7 I/O STREAM CLASSES
OBJECTIVE:
Implementation of various file classes supported by Java for reading and writing to the file
OVERVIEW:
Introduction:
All programs accept input from user, process the input and produce output. Therefore, all
programming languages support the reading of input and display of output. Java handles all input and output
in form of streams. A stream is a sequence of bytes traveling from a source to destination over a
communication path. When a stream of data is being sent, it is said to be written, and when a stream of data
is being received, it is said to be read.
Implementing the File class:
File are the primary source and destination for storing the data contain in the programs. Java
provide the java.io package for performing I/O operation. This include File class.
File class Constructors:
Constructor Description
File(File parent, String child) This constructor is used to create a new File object with the
parent path name and child pathname.
Syntax : public File(File parent, String child)
File(String pathname) This constructor is used to create a new File object with
specified file pathname.
Syntax : public File(String pathname)
File(String parent, String
child)
This constructor is used to create a new File object with the
specified parent pathname and child pathname.
Syntax : public File(String parent, String child)
File(URI uri) This constructor is used to create a new File object by
converting a specified URI into pathname.
Syntax : public File(URI uri)
Methods in File class:
Method Descrption
public boolean canExecute() This method is used for testing that whether the file can
be executed by the application or not.

28
public boolean canRead() : This method is used for testing that whether the file can
be read by the application or not.
public boolean canWrite() This method is used for testing that whether the file can
be write by the application or not.
public int compareTo(File
pathname)
This method is used to compare two file pathname.
public boolean
createNewFile() throws
IOException
This method is used for creating a new empty file with
the specified name.
public static File
createTempFile(String
prefix,String suffix) throws
IOException
This method is used for creating an empty file in the
default temporary file directory. prefix and suffix are
used for specifying the name of file.
public static File
createTempFile(String
prefix, String suffix, File
directory) throws
IOException
This method is used for creating an empty file in the
given directory. prefix and suffix are used for specifying
the name of file.
public boolean delete() This method is used for deleting the specified file or
directory.
public void deleteOnExit() This method is used for deleting the specified file or
directory on the termination of JVM.
public boolean equals(Object
obj)
This method is used to test whether the specified Object
is equal to the pathname or not.
public boolean exists() This method is used to test whether the specified
pathname is existed or not.

29
public File getAbsoluteFile() This method is used to get the absolute form of
pathname.
public String
getAbsolutePath()
This method is used to get the absolute pathname. This
pathname is retrieved as string.
public long getFreeSpace() This method is used to find out the unallocated bytes in
the partition (portion of storage for a file system.)
public String getName() This method is used to find out the name of file or
directory of the specified pathname.
public String getParent() This method is used to find out the parent of the specified
pathname.
public File getParentFile() This method is used to find out the parent of the specified
pathname.
public String getPath() This method is used to find out the path of the file or
directory as string.
public long getTotalSpace() This method is used to find out the size of the partition.
public long getUsableSpace() This method is used to find out the number of bytes made
available to the VM when the partition named by the
pathname.
public int hashCode() This method is used for computing a hash code for
pathname.
public boolean isAbsolute() This method is used for testing that whether the
pathname is absolute or not.
public boolean isDirectory() This method is used for testing that whether the specified
pathname is directory or not.
public boolean isFile() This method specifies whether the specified file name is
a normal file or not.
public boolean isHidden() This method specifies, whether the file is a hidden file or
not.
public long lastModified() This method is used to get the time in which the file was
last modified.
public long length() This method is used to get the length of the file.

30
public String[] list() This method is used to get the list of files and directories
(as an array of strings) in the specified directory
public String[]
list(FilenameFilter filter)
This method is used to get the list of files and directories
(as an array of strings) in the specified directory which
specifies a specified filter.
public File[] listFiles() This method is used to get the (an array) pathnames
which represents files in the directory.
public File[]
listFiles(FileFilter filter)
This method is used to get the (an array) pathnames
which represents files and directories in the specified
directory which specifies a specified filter.
public File[]
listFiles(FilenameFilter
filter)
This method is used to get the (an array) pathnames
which represents files and directories in the specified
directory which specifies a specified filter.
public static File[] listRoots() This method is used to list the file system roots (if
available).
public boolean mkdir() This method is used to create a directory with the
specified pathname.
public boolean mkdirs() This method is used to create a directory with the
specified pathname.
public boolean
renameTo(File dest)
This method is used to rename the file specified by the
pathname.
public boolean
setExecutable(boolean
executable)
This method is used to set the permission of execution of
files.
public boolean
setExecutable(boolean
executable, boolean
ownerOnly)
: This method is used to set the permission of execution
of files.
public boolean
setLastModified(long time)
This method is used to set the file's or directory's last
modified time.

31
public boolean
setReadable(boolean
readable)
This method is used to set the permission of file to read.
public boolean
setReadable(boolean
readable, boolean
ownerOnly)
This method is used to set the permission of file to read.
public boolean
setReadOnly()
This method is used to set the file's or directory's to
allowed only for read operation.
public boolean
setWritable(boolean
writable)
allowed only for write operation
public boolean
setWritable(boolean
writable, boolean
ownerOnly)
allowed only for write operation.
public String toString() : This method is used to get the pathname of the specified
abstract pathname as string.

32
Sample coding:
/**
*
*/
import java.io.*;
public class Eleventh_Program {
public static void main(String[] args) throws IOException
{
File f;
f=new File("D:/myfile.txt");
if(!f.exists())
{
f.createNewFile();
System.out.println(“New file "myfile.txt" has been created to the
given directory);
}
else
{
System.out.println("The specified file is already exist");
}
}
}
Output:
run:
New file "myfile.txt" has been created to the given directory

33
Screenshot:
Using Streams in Java:
Accessing File using the InputStream Class:
InputStream are the byte streams that read data in the form of byte. Java providing classes are
shown below,
InputStream
SequenceInputStream ObjectInputStream PipedInputStream ByteArrayInputStream FilterInputStream FileInputStream
PushbackInputStream BufferedInputStreamDataInputStream

34
Using Streams in Java:
Accessing File using the OutputStream Class:
OutputStream are the byte streams that write data in the form of byte. Java providing classes
are shown below,
Implementing Character Stream Classes:
Using the Reader Class:
The Reader class is used to read characters from the character streams. The Reader class
cannot be instantiated since it is an abstract class. Therefore, the object of its subclasses are used for
reading Unicode character data.
OutputStream
ObjectOutputStream PipedOutputStream ByteArrayOutputStream FilterOutputStream FileOutputStream
BufferedOutputStreamDataOutputStream
Reader
BufferedReader LineNumberReader
StringReader
InputStreamReader FileReader
PipedReader
FilterReader PushbackReader
CharArrayReader

35
Using the Writer class:
The Writer class is used to write characters from the character streams. The Writer class
cannot be instantiated since it is an abstract class. Therefore, the object of its subclasses are used for
writing character data to a character stream.
Sample coding:
/**
*
*/
public class Twelfth_Program {
public static void main(String arg[]) throws FileNotFoundException, IOException
{
char ch;
File f=new File("D:/test.txt");
FileReader fr=new FileReader(f);
//Reading a content from file
while(fr.ready())
{
ch=(char)fr.read();
System.out.print(ch);
}
fr.close();
} }
Writer BufferedWriter
StringWriter
OutputStreamWriter FileWriter
PipedWriter
FilterWriter
CharArrayWriter

36
Output:
run:
Hello!!! world
Snapshot:

37
Sample coding:
/**
*
*/
public class Twelfth_Program {
public static void main(String arg[]) throws FileNotFoundException, IOException
{
String str="Writer working";
File f=new File("D:/test.txt");
FileWriter fw=new FileWriter(f);
fw.write(str);
fw.close();
}
}
Output:
run:
Snapshot:

38
PRE LAB EXERCISE
a. Write a Java Program to print size of a file
b. Write a Java program to copy the text file using InputStream and OutputStream
IN LAB EXERCISE
a. Write a Java program to get absolute path of the file
b. Write a Java program to read the entire text file, eliminate all special characters in it and write the
content in the same text file
I/O test.txt
Hai!! How Are You?
O/P test.txt
HaiHowAreYou
POST LAB EXERCISE
a. Write a Java program to delete a file
b. Write a Java program to prove the following mathematics notations,
1. n(n + l)(2n + 1) is always divisible by 6.
2. 32n
leaves remainder = 1 when divided by 8
3. n3
+ (n + 1 )3
+ (n + 2 )3
is always divisible by 9
4. 102n + 1
+ 1 is always divisible by 11
5. n(n2
– 1) is always divisible by 6
6. n2
+ n is always even
7. 23n
-1 is always divisible by 7
8. 152n-1
+l is always divisible by 16
9. n3
+ 2n is always divisible by 3
10. 34n
– 4 3n
is always divisible by 17
*(Note get the value of n from the text file)
Result:

39
8 APPLETS AND SWINGS
OBJECTIVE:
Creating GUI using Java programming.
OVERVIEW:
Applet:
Applet are Java program that executes inside a Web page. Therefore, unlike applications, applet
require a Java enabled browsers like Internet Explorer or Netscape etc. An applet loaded and executed when
a user load a Web page through Wed browser.
Applet Life Cycle:
Various Graphics Methods:
S.No Method Purpose
1
public void init() Called once by the applet container when an applet is loaded for
execution. This method initializes an applet. Typical actions
performed here are initializing ﬁelds, creating GUI components,
loading sounds to play, loading images to display
2
public void start() Called by the applet container after method init completes execution.
In addition, if the user browses to another website and later returns to
the applet’s HTML page, method start is called again. The method
performs any tasks that must be completed when the applet is loaded
for the ﬁrst time and that must be performed every time the applet’s
HTML page is revisited. Actions performed here might include
starting an animation
3
public void paint(
Graphics g )
Called by the applet container after methods init and start. Method
paint is also called when the applet needs to be repainted. For example,
if the user covers the applet with another open window on the screen
and later uncovers the applet, the paint method is called. Typical
actions performed here involve drawing with the Graphics object g that
is passed to the paint method by the applet container
4
public void stop() This method is called by the applet container when the user leaves the
applet’s web page by browsing to another web page. Since it is
possible that the user might return to the web page containing the
applet, method stop performs tasks that might be required to suspend
the applet’s execution, so that the applet does not use computer
processing time when it is not displayed on the screen. Typical actions
performed here would stop the execution of animations
5
public void destroy() This method is called by the applet container when the applet is being
removed from memory. This occurs when the user exits the browsing
session by closing all the browser windows

40
Method Description
abstract void clearRect(int x, int y, int width,
int height)
Clears the specified rectangle by filling it
with the background color of the current
drawing surface.
abstract void clipRect(int x, int y, int width, int height) Intersects the current clip with the
specified rectangle.
abstract void copyArea(int x, int y, int width,
int height, int dx, int dy)
Copies an area of the component by a
distance specified by dx and dy.
abstract Graphics create()
Creates a new Graphics object that is a
copy of this Graphics object.
Graphics create(int x, int y, int width, int height) Creates a new Graphics object based on
this Graphics object, but with a new
translation and clip area.
abstract void dispose() Disposes of this graphics context and
releases any system resources that it is
using.
void draw3DRect(int x, int y, int width, int height,
boolean raised)
Draws a 3-D highlighted outline of the
abstract void drawArc(int x, int y, int width,
int height, int startAngle, int arcAngle) Draws the outline of a circular or elliptical
arc covering the specified rectangle.
void drawBytes(byte[] data, int offset, int length, int x,
int y)
Draws the text given by the specified byte
array, using this graphics context's current
font and color.
void drawChars(char[] data, int offset, int length,
int x, int y)
Draws the text given by the specified
character array, using this graphics
context's current font and color.
abstract boolean drawImage(Image img, int x, int y,
Color bgcolor, ImageObserver observer)
Draws as much of the specified image as is
currently available.
ImageObserver observer)
draws as much of the specified image as is
currently available.
int width, int height, Color bgcolor,
ImageObserver observer)
Draws as much of the specified image as
has already been scaled to fit inside the
int width, int height, ImageObserver observer)
Draws as much of the specified image as
has already been scaled to fit inside the
abstract booleandrawImage(Image img, int dx1,
int dy1, int dx2, int dy2, int sx1, int sy1, int sx2,
int sy2, Color bgcolor, ImageObserver observer)
Draws as much of the specified area of the
specified image as is currently available,
scaling it on the fly to fit inside the
specified area of the destination drawable
surface.
abstract boolean drawImage(Image img, int dx1,
int dy1, int dx2, int dy2, int sx1, int sy1, int sx2,
int sy2, ImageObserver observer)
Draws as much of the specified area of the
specified image as is currently available,
scaling it on the fly to fit inside the
specified area of the destination drawable
surface.

41
abstract void drawLine(int x1, int y1, int x2, int y2) Draws a line, using the current color,
between the points (x1, y1) and (x2, y2) in
this graphics context's coordinate system.
abstract void drawOval(int x, int y, int width,
int height)
Draws the outline of an oval.
abstract void drawPolygon(int[] xPoints, int[] yPoints,
int nPoints)
Draws a closed polygon defined by arrays
of x and y coordinates.
void drawPolygon(Polygon p) Draws the outline of a polygon defined by
the specified Polygon object.
abstract void drawPolyline(int[] xPoints, int[] yPoints,
int nPoints)
Draws a sequence of connected lines
defined by arrays of x and y coordinates.
void drawRect(int x, int y, int width, int height) Draws the outline of the specified
rectangle.
abstract void drawRoundRect(int x, int y, int width,
int height, int arcWidth, int arcHeight) Draws an outlined round-cornered
rectangle using this graphics context's
current color.
abstract void
drawString(AttributedCharacterIterator iterator,
int x, int y)
Renders the text of the specified iterator
applying its attributes in accordance with
the specification of the TextAttribute class.
abstract void drawString(String str, int x, int y)
Draws the text given by the specified
string, using this graphics context's current
font and color.
void fill3DRect(int x, int y, int width, int height,
boolean raised) Paints a 3-D highlighted rectangle filled
with the current color.
abstract void fillArc(int x, int y, int width, int height,
int startAngle, int arcAngle)
Fills a circular or elliptical arc covering the
abstract void fillOval(int x, int y, int width, int height) Fills an oval bounded by the specified
rectangle with the current color.
abstract void fillPolygon(int[] xPoints, int[] yPoints,
int nPoints)
Fills a closed polygon defined by arrays of
x and y coordinates.
void fillPolygon(Polygon p)
Fills the polygon defined by the specified
Polygon object with the graphics context's
current color.
abstract void fillRect(int x, int y, int width, int height)
Fills the specified rectangle.
abstract void fillRoundRect(int x, int y, int width,
int height, int arcWidth, int arcHeight)
Fills the specified rounded corner rectangle
with the current color.
void finalize() Disposes of this graphics context once it is
no longer referenced.
abstract Shape getClip() Gets the current clipping area.

42
Sample coding:
/**
*
*/
import java.applet.Applet;
import java.awt.Graphics;
abstract Rectangle getClipBounds() Returns the bounding rectangle of the
current clipping area.
Rectangle getClipBounds(Rectangle r)
Returns the bounding rectangle of the
current clipping area.
Rectangle getClipRect()
Deprecated.
As of JDK version 1.1, replaced by
getClipBounds().
abstract Color getColor() Gets this graphics context's current color.
abstract Font getFont() Gets the current font.
FontMetrics getFontMetrics() Gets the font metrics of the current font.
abstract FontMetrics getFontMetrics(Font f)
Gets the font metrics for the specified font.
boolean hitClip(int x, int y, int width, int height)
Returns true if the specified rectangular
area might intersect the current clipping
area.
abstract void setClip(int x, int y, int width, int height) Sets the current clip to the rectangle
specified by the given coordinates.
abstract void setClip(Shape clip) Sets the current clipping area to an
arbitrary clip shape.
abstract void setColor(Color c) Sets this graphics context's current color to
the specified color.
abstract void setFont(Font font) Sets this graphics context's font to the
specified font.
abstract void setPaintMode() Sets the paint mode of this graphics
context to overwrite the destination with
this graphics context's current color.
abstract void setXORMode(Color c1) Sets the paint mode of this graphics
context to alternate between this graphics
context's current color and the new
specified color.
String toString() Returns a String object representing this
Graphics object's value.
abstract void translate(int x, int y) Translates the origin of the graphics
context to the point (x, y) in the current
coordinate system.

43
import javax.swing.JOptionPane;
public class Fourteenth extends Applet {
private double sum;
/**
* Initialization method that will be called after the applet is loaded into
* the browser.
*/
public void init() {
String firstNumber;
String secondNumber;
double number1;
double number2;
firstNumber = JOptionPane.showInputDialog( "Enter first floating-point
value" );
secondNumber = JOptionPane.showInputDialog( "Enter second floating-point
value" );
number1 = Double.parseDouble( firstNumber );
number2 = Double.parseDouble( secondNumber );
sum = number1 + number2;
}
public void paint( Graphics g )
{
super.paint( g );
g.drawRect( 15, 10, 270, 20 );
g.drawString( "The sum is " + sum, 25, 25 );
}
// TODO overwrite start(), stop() and destroy() methods
}

44
Screenshot:

45
Working with AWT Control Components:
Java provides the AWT control components, which contain classes that enables us to create standard
components such as buttons, labels and text field in Java.
Various AWT Components:
Some of the AWT component classes are,
 TextField
 TextArea
 Button
 List
 CheckBox
 Choice
 Label
Working with Swing Components:
Swing components also provide GUI environment to Java in addition to applet. Swing components
are the collection of lightweight visual component that provide a replacement for heavy weight AWT
components.
Identifying the Swing Component Class Hierarchy:
The JComponents class is the root of the Swing hierarchy. The class hierarchy of the Swing
components is categorized into:
1. Top-level swing containers: It act as a container for placing the intermediate-level and atomic
components, such as panels, buttons, checkbox.
a. JFrame
b. JApplet
c. JDialog
2. Intermediate-level swing container: It placed on top-level container and contains atomic
components, such as buttons, checkbox and labels.
a. JPanel
b. JtabbedPane
c. JScrollPane
d. JToolBar
3. Atomic components: It placed on the intermediate-level swing container. Atomic components are
used to accept input from a user.
a. JTextField
b. JButton
c. JCheckBox
d. JLabel
e. JTable

46
Steps to create and work with JFrame using NetBean IDE:
1. File->New Project
2. New Project dialog box will appear
3. In Categories click Java, in Projects click Java Application and click Next
4. Give Project Name, uncheck the Create Main Class and click Finish
5. Project created. Right Click in the project in the Project Explorer tab
6. New->JFrame Form
7. New JFrame Form will appear
8. Give Class Name and click Finish
9. An empty JFrame is created
10. We can find Palette Explorer in Right side of the NetBean IDE. If not go to
Window ->Palette or Ctrl+Shift+8
11. Drag and Drop needed components to the Frame

47
12. To change the JLabel name or to resize the component. We can find Properties
Explorer in Right side of the NetBean IDE. If not go to Window ->Properties or
Ctrl+Shift+7
13. To view the Frame actual visible. Click Preview Design

48
PRE LAB EXERCISE
a. Draw any one smiley you known in JApplet
b. Create a Register form GUI for School Administration purpose using JFrame
IN LAB EXERCISE
a. An analysis of examination result at a school gave the following distribution of grades for all
subject taken in the year:
Grade Percentage
A 10
B 25
C 45
D 60
E 85
Write a Java program to represent the distribution of each grade in bar char
b. Create a Calculator GUI using JFrame
POST LAB EXERCISE
a. Draw a 3D rectangle without using Graphics method in JApplet
b. Create a Notepad GUI using JFrame
Result:

49
9 EVENT-HANDLING
OBJECTIVE:
Detailed study on Event classes in java
OVERVIEW:
Event:
An object that describes a state of change in a source component is called an event. In Java, events
are supported by the classes and interfaces defined in the java.awt.event package.
Event Classes:
Event Handling Classes and Methods
ActionListener actionPerformed(ActionEvent) addActionListener()
AdjustmentListener adjustmentValueChanged(Adjustment
Event)
addAdjustmentListener(
)
ComponentListener componentHidden(ComponentEvent)
componentMoved(ComponentEvent)
componentResized(ComponentEvent)
componentShown(ComponentEvent)
addComponentListener(
)
ContainerListener componentAdded(ContainerEvent)
componetRemoved(ContainerEvent)
addContainerListener()
Java.util.EventObject
Java.util.AWTEvent
ItemEvent
Adjustment
Event
FocusEvent
Component
Event
ContainerEv
ent
FocusEvent InputEvent
MouseEvent KeyEvent
PaintEvent
WindowEve
nt
ActionEvent TextEvent

50
FocusListener focusGained(FocusEvent)
focusLost(FocusEvent)
addFocusListener()
ItemListener itemStateChanged(ItemEvent) addItemListener()
KeyListener keyPressed(KeyEvent)
keyReleased(KeyEvent)
keyTyped(KeyEvent)
addKeyListener()
MouseListener mouseClicked(MouseEvent)
mouseEntered(MouseEvent)
mouseExited(MouseEvent)
mousePressed(MouseEvent)
mouseReleased(MouseEvent)
addMouseListener()
MouseMotionListene
r
mouseDragged(MouseEvent)
mouseMoved(MouseEvent)
addMouseMotionListen
er()
TextListener textValueChanged(TextEvent) addTextListener()
WindowListener windowActivated(WindowEvent)
windowClosed(WindowEvent)
windowClosing(WindowEvent)
windowDeactivated(WindowEvent)
windowDeiconified(WindowEvent)
windowIconified(WindowEvent)
windowOpened(WindowEvent)
addWindowListener()
Steps to work with Event handling in NetBean IDE:
 Open a NewJFrame, class name is Fifteenth and drag necessary components

51
 For above example, We going to perform ActionEvent on jButton1 (Login)
 Right click on the button, click Event->Action->actionPerformed[jButton1ActionPerformed]
 private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) method created in the
Fiveteenth.java file. We can view that method by clicking source tab.

52
 Write the following code in the private void
jButton1ActionPerformed(java.awt.event.ActionEvent evt) method,
 Run the program
When we give the Username and
Password field matches to the if
condition in program
When we give the Username and
Password field mismatch to the if
condition in program

53
PRE LAB EXERCISE
a. Create a Register form for School Administration purpose using JFrame and If the details were
entered click Register button. If the Register button is clicked, display the given options in next
Frame
IN LAB EXERCISE
a. Create a Scientific Calculator using JFrame (Use standard Math methods for calculation)
b. Rotate a compass needle on the screen about a fixed point in response to the mouse being moved
around the screen.
POST LAB EXERCISE
a. Create a JFrame (as shown below) to access the FileChooser to select file. After selecting the file
the content of the file displayed in the JTextArea.
Result:

54
10 MULTITHREADING
OBJECTIVE:
Creating Thread and demonstrate Multithreading concept
OVERVIEW:
Thread:
A thread can be defined as the single sequential flow of control within the program. It is a
sequence of instruction that is executed to define a unique flow of control. For example: A CPU performs
various process simultaneously, such as writing and printing a document, installing a software, and
displaying the date and time on status bar.
The process that is made of one thread is known as single-threaded process. A process that
creates two or more threads is called a multi-thread process. For example: Any Web browser, such as
Microsoft Edge, is a multi-threaded application.
Every Java program uses threads:
Every Java program has at least one thread i.e. main thread. When a Java program starts, the
JVM creates the main thread and call the program main() method within that thread. The JVM also creates
other threads that are mostly invisible to us. For example: Threads associate with garbage collection,
object finalization, and other JVM housekeeping tasks. Other facilities create threads too, such as the
AWT or Awing UI toolkits, servlet containers, application servers and RMI(Remote Method Invocation).
Benefits of Multithreading:
 Improved performance
 Minimized system resource usage
 Simultaneous access to multiple application
 Program structure simplification
Pitfalls of Multithreading:
 Race Condition
 Deadlock Condition
 Lock Starvation

55
Life Cycle of a Thread:
The various states in the life cycle of the thread are:
 New
 Runnable
 Not Runnable
 Terminate or Dead
The following figure shows the life cycle of a thread.
Creating Thread:
We create thread by instantiating an object of the Thread class. We can create a thread in the
following ways,
1. Implementing the Runnable interface
2. Extending the Thread class
Creating Thread by implementing the Runnable Interface:
If Applet extends the Applet class. Since Java does not support multiple inheritance, we cannot
inherit both Applet and Thread. So, Java provide us Runnable Interface.
Terminate
New Thread
Created
Suspended
RunnableSleeping
resume( ) run( ) suspend( )
sleep( )
timeout( )
stop( )

56
Sample coding:
/**
*
*/
import java.util.logging.Level;
import java.util.logging.Logger;
class Sixteenth1 implements Runnable{
Sixteenth1()
{
Thread t = new Thread(this,"mythread");
t.start();
}
@Override
public void run() {
System.out.println("Child class");
}
}
class Sixteenth2{
{
new Sixteenth1();
System.out.println("Main class");
try {
Thread.sleep(20);
} catch (InterruptedException ex) {
Logger.getLogger(Sixteenth2.class.getName()).log(Level.SEVERE, null,
ex);
}
}
}
Output:
run:
Main class
Child class

57
Sample coding:
/**
*
*/
import java.util.logging.Level;
import java.util.logging.Logger;
class Seventeenth1 extends Thread{
Seventeenth1()
{
Thread t = new Thread(this,"mythread");
t.start();
}
@Override
public void run() {
System.out.println("Child class");
}
}
class Seventeenth1{
{
new Seventeenth1();
try {
Thread.sleep(2000);
} catch (InterruptedException ex) {
Logger.getLogger(Sixteenth2.class.getName()).log(Level.SEVERE, null,
ex);
}
System.out.println("Main class");
}
}
Output:
run:
Child class
Main class
PRE LAB EXERCISE

58
*******************************NILL************************************
IN LAB EXERCISE
a. Illustrate Multi-Thread concept with suitable example
POST LAB EXERCISE
*******************************NILL************************************
Result:

59
11 NETWORKING-I
OBJECTIVE:
Java Programming on basic networking protocols
OVERVIEW:
Introduction:
One of the important features of java are networking support. Java provides fundamental
networking capabilities through java.net package.
OSI layers:
Communication between computers in network
Layer 7: Application Layer
 Defines interface to user processes for communication and data transfer in network
 Provides standardized services such as virtual terminal, file and job transfer and operations
Layer 6: Presentation Layer
 Masks the differences of data formats between dissimilar systems
 Specifies architecture-independent data transfer format
 Encodes and decodes data; encrypts and decrypts data; compresses and decompresses data

60
Layer 5: Session Layer
 Manages user sessions and dialogues
 Controls establishment and termination of logic links between users
 Reports upper layer errors
Layer 4: Transport Layer
 Manages end-to-end message delivery in network
 Provides reliable and sequential packet delivery through error recovery and flow control
mechanisms
 Provides connectionless oriented packet delivery
Layer 3: Network Layer
 Determines how data are transferred between network devices
 Routes packets according to unique network device addresses
 Provides flow and congestion control to prevent network resource depletion
Layer 2: Data Link Layer
 Defines procedures for operating the communication links
 Frames packets
 Detects and corrects packets transmit errors
Layer 1: Physical Layer
 Defines physical means of sending data over network devices
 Interfaces between network medium and devices
 Defines optical, electrical and mechanical characteristics
Protocol:
A protocol is a set of rules and standard for communication. A network protocol specifies the
format of data being sent over the network, along with necessary details. The important protocols used in
the Internet are:
1. IP(Internet Protocol):
Internet Protocol is a network layer protocol that breaks the data into packets and sent
them using IP address.
2. TCP(Transmission Control Protocol):
It is a used for connection oriented communication between two applications on two
different machines.
3. UDP(User Datagram Protocol):
It is a used for connectionless oriented communication between two applications on two
different machines.

61
Internet Address:
An Internet address uniquely identifies a node on the Internet. Internet address may also refer to
the name or IP of a Web site (URL). The term Internet address can also represent someone's e-mail
address
InetAddress class in Java:
It is a class in Java which represents an Internet Protocol (IP) address. An instance of an InetAddress
consists of an IP address and possibly corresponding hostname.
The Class represents an Internet address as Two fields:
1. Host name (The String)=Contain the name of the Host.
2. Address(an int)= The 32 bit IP address.
These fields are not public, so we can’t Access them directly. There is not public constructor in InetAddress
class, but it has 3 static methods that returns suitably initialized InetAddress. Objects namely Public String
getHostName() , public byte[] getAddress() and public String getHostAddress()
Methods Description
boolean equals(Object obj) Compares this object against the
specified object.
byte[] getAddress() Returns the raw IP address of this
InetAddress object.
static InetAddress[]getAllByName(String host) Given the name of a host, returns an
array of its IP addresses, based on the
configured name service on the system.
static InetAddress getByAddress(byte[] addr) Returns an InetAddress object given the
raw IP address.
static InetAddress getByAddress(String host,
byte[] addr)
Creates an InetAddress based on the
provided host name and IP address.
static InetAddress getByName(String host) Determines the IP address of a host,
given the host's name.
String getCanonicalHostName() Gets the fully qualified domain name for
this IP address.
String getHostAddress() Returns the IP address string in textual
Presentation.
String getHostName() Gets the host name for this IP address.
static InetAddress getLocalHost() Returns the address of the local host.
static InetAddress getLoopbackAddress() Returns the loopback address.
Int hashCode() Returns a hashcode for this IP address.
boolean isAnyLocalAddress() Utility routine to check if the
InetAddress in a wildcard address.
boolean isLinkLocalAddress() Utility routine to check if the
InetAddress is an link local address.
boolean isLoopbackAddress() Utility routine to check if the
InetAddress is a loopback address.
boolean isMCGlobal() Utility routine to check if the multicast
address has global scope.

62
boolean isMCLinkLocal() Utility routine to check if the multicast
address has link scope.
boolean isMCNodeLocal() Utility routine to check if the multicast
address has node scope.
boolean isMCOrgLocal() Utility routine to check if the multicast
address has organization scope.
boolean isMCSiteLocal() Utility routine to check if the multicast
address has site scope.
boolean isMulticastAddress() Utility routine to check if the
InetAddress is an IP multicast address.
boolean isReachable(int timeout) Test whether that address is reachable.
boolean isReachable(NetworkInterface netif, int ttl,
int timeout)
Test whether that address is reachable.
boolean isSiteLocalAddress() Utility routine to check if the
InetAddress is a site local address.
String toString() Converts this IP address to a String.
Sample coding:
To print IP address of LocalHost:
/**
*
*/
public class Eighteenth_Program {
{
try
{
InetAddress IPO=InetAddress.getLocalHost();
System.out.println("IP of this system= "+IPO.getHostAddress());
}
catch(Exception e)
{
System.err.println("Exception: "+e.getMessage());
}
}
}

63
Output:
run:
IP of this system= 127.0.0.1
TCP (Transmission Control Protocol):
Creating TCP Servers:
To create a TCP server, do the following:
1. Create a ServerSocket attached to a port number.
ServerSocket server = new ServerSocket(port);
2. Wait for connections from clients requesting connections to that port.
// Block on accept()
Socket channel = server.accept();
We get a Socket object as a result of the connection.
3. Get input and output streams associated with the socket.
out = new PrintWriter (channel.getOutputStream());
reader = new InputStreamReader (channel.getInputStream());
in = new BufferedReader (reader);
Now you can read and write to the socket, thus, communicating with the client.
String data = in.readLine();
out.println("Welcome!!");
When a server invokes the accept() method of the ServerSocket instance, the main server thread
blocks until a client connects to the server; it is then prevented from accepting further client connections
until the server has processed the client's request. This is known as an iterative server, since the main
server method handles each client request in its entirety before moving on to the next request. Iterative
servers are good when the requests take a known, short period of time. For example, requesting the current
day and time from a time-of-day server.

64
Creating TCP Clients:
To create a TCP client, do the following:
1. Create a Socket object attached to a remote host, port.
Socket client = new Socket(host, port);
When the constructor returns, you have a connection.
2. Get input and output streams associated with the socket.
out = new PrintWriter (client.getOutputStream());
reader = new InputStreamReader (client.getInputStream());
in = new BufferedReader (reader);
Now you can read and write to the socket, thus, communicating with the server.
out.println("Hi!! This is me your client");
String data = in.readLine();

65
Sample coding:
Implementation of Client Server Communication Using TCP
CliTCP:
/**
*
*/
import java.lang.*;
import java.net.*;
import java.io.*;
class CliTCP
{
public static void main(String args[]) throws UnknownHostException
{
try {
Socket skt=new Socket("",1234);
BufferedReader in=new BufferedReader(new
InputStreamReader(skt.getInputStream()));
System.out.println("Received string:");
while(!in.ready()) {}
System.out.println(in.readLine());
System.out.println("n"); in.close();
}
catch(Exception e) {
System.out.println("Whoops! It didn't work! n");
}
}
}

66
SerTCP:
/**
*
*/
import java.lang.*; import java.net.*; import java.io.*;
class SerTCP
{
public static void main(String args[])
{
String data="Welcome";
try {
ServerSocket s=new ServerSocket(1234);
Socket skt=s.accept();
System.out.println("Server has connected! n");
PrintWriter out=new PrintWriter(skt.getOutputStream(),true);
System.out.println("Sending string: n "+data+"n");
out.print(data);
out.close();
skt.close();
s.close();
}
catch(Exception e)
{
System.out.println("Whoops! It didn't work! n");
}
}
}
Output:
Clientside:
run:
Received string:
Welcome

67
Serverside:
run:
Server has connected!
Sending string:
Welcome
PRE LAB EXERCISE
a. Write a Java Program to print MAC address of the local host
IN LAB EXERCISE
a. Create a Simple Chat Application using TCP
b. Create a Simple Game Application using TCP
POST LAB EXERCISE
a. Create a Simple Chat Application using TCP (Note: Create JFrames Application)
Result:

68
12 NETWORKING-II
OBJECTIVE:
Java Programming on basic networking protocols
OVERVIEW:
UDP (User Datagram Protocol):
Creating UDP Servers:
To create a server with UDP, do the following:
1. Create a DatagramSocket attached to a port.
int port = 1234;
DatagramSocket socket = new DatagramSocket(port);
2. Allocate space to hold the incoming packet, and create an instance of DatagramPacket to
hold the incoming data.
byte[] buffer = new byte[1024];
DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
3. Block until a packet is received, then extract the information you need from the packet.
// Block on receive()
socket.receive(packet);
// Find out where packet came from
// so we can reply to the same host/port
InetAddress remoteHost = packet.getAddress();
int remotePort = packet.getPort();
// Extract the packet data byte[] data = packet.getData();
The server can now process the data it has received from the client, and issue an appropriate
reply in response to the client's request.

69
Creating UDP Client:
Writing code for a UDP client is similar to what we did for a server. Again, we need a DatagramSocket and
a DatagramPacket. The only real difference is that we must specify the destination address with each
packet, so the form of the DatagramPacket constructor used here specifies the destination host and port
number. Then, of course, we initially send packets instead of receiving.
1. First allocate space to hold the data we are sending and create an instance of DatagramPacket to
hold the data.
byte[] buffer = new byte[1024];
int port = 1234;
InetAddress host = InetAddress.getByName("magelang.com");
DatagramPacket packet = new DatagramPacket(buffer, buffer.length, host, port);
2. Create a DatagramSocket and send the packet using this socket.
DatagramSocket socket = new DatagramSocket();
socket.send(packet);
The DatagramSocket constructor that takes no arguments will allocate a free local port to use.
You can find out what local port number has been allocated for your socket, along with other information
about your socket if needed.
// Find out where we are sending from InetAddress localHostname = socket.getLocalAddress();
int localPort = socket.getLocalPort();
The client then waits for a reply from the server. Many protocols require the server to reply to the
host and port number that the client used, so the client can now invoke socket.receive() to wait for
information from the server.

70
Sample coding:
Implementation of socket program for UDP Echo Client and Echo Server:
CliUDP:
/**
*
*/
import java.net.*;
import java.io.*;
import java.lang.*;
public class CliUDP {
public static void main(String args[])throws IOException {
byte[] buff=new byte[1024];
DatagramSocket soc=new DatagramSocket(9999);
String s="From client-Hello Server";
buff=s.getBytes();
InetAddress a=InetAddress.getLocalHost();
DatagramPacket pac=new DatagramPacket(buff,buff.length,a,8888);
soc.send(pac);
System.out.println("End of sending");
byte[] buff1=new byte[1024];
buff1=s.getBytes();
pac=new DatagramPacket(buff1,buff1.length);
soc.receive(pac);
String msg=new String(pac.getData());
System.out.println(msg);
System.out.println("End of programming");
}
}

71
SerUDP:
/**
*
*/
import java.net.*;
import java.io.*;
import java.lang.*;
public class ES {
public static void main(String args[])throws IOException {
byte[] buff=new byte[512];
DatagramSocket soc=new DatagramSocket(8888);
DatagramPacket pac=new DatagramPacket(buff,buff.length );
System.out.println("server started");
soc.receive(pac);
String msg=new String(pac.getData());
System.out.println(msg);
System.out.println("End of reception");
String s="From Server-Hello client";
byte[] buff1=new byte[512];
buff1=s.getBytes();
InetAddress a=pac.getAddress();
int port=pac.getPort();
pac=new DatagramPacket(buff,buff1.length,a,port);
soc.send(pac);
System.out.println("End of sending");
}
}
Output:
Clientside:
run:
End of sending
From client-Hello Server
End of programming

72
ServerSide:
run:
server started
From client-Hello Server
End of reception
End of sending
PRE LAB EXERCISE
a. Design UDP Client and Server application to reverse the given input sentence.
IN LAB EXERCISE
a. Design UDP Client Server to transfer a file
POST LAB EXERCISE
*******************************NILL************************************
Result:

1
Contact Person1:
Mr. Naveen Sagayaselvaraj
Email ID:
naveensagayaselvaraj@gmail.com
Website:
https://sites.google.com/site/naveensagayaselvaraj/
Contact Person2:
Ms. Mangaiyarkkarasi V
Email ID: v.mangai.2010@gmail.com

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