The document provides code snippets for various Java programs involving classes, objects, inheritance, packages, exceptions, threads, file handling, database operations, and servlets. It includes 22 sections that demonstrate concepts like class syntax, method overriding and overloading, communication between classes, abstract classes, packages, try-catch blocks, user threads, multiple threads, file input/output, database insertion and fetching, servlets for form submission and passing values between servlets.

1. B.Tech CS
Object Oriented Techniques
Practical File
Sudeep Singh

2. Syntax Of Classes
♦♦ Simple class ♦♦
<class- keyword> <class- name>
{
<method- access specifier> <type- return/non_return> <method- name>()
{ operations }
}
♦♦ static top most class ♦♦
<static- keyword><class- keyword> <class- name>
{
<method- access specifier> <type- return/non_return> <method- name>()
{ operations }
}
♦♦ main class ♦♦
<class- keyword> <class- name>
{
public static void main (String [ ]s )
{
System.out.println(“Welcome In BHABHA GROUP OF INSTITUTION”) ;
}
}

3. ♦♦1 program to add two number ♦♦
class sum
{
public static void main(String[]s)
{
int a,b,c;
a=Integer.parseInt(s[0]);
b=Integer.parseInt(s[1]);
c=a+b;
System.out.println("sum = "+c);
} }
♦♦2 program to multiply two number ♦♦
class multi
{
public static void main(String[]s)
{
int a,b,c;
a=Integer.parseInt(s[0]);
b=Integer.parseInt(s[1]);
c=a*b;
System.out.print("sum = "+c);
}
}

4. ♦♦3 program to print factorial of any number ♦♦
class factorial
{
public static void main(String[]s)
{
int a,f=1;
a=Integer.parseInt(s[0]);
for(int i=a;i>=1;i--)
{ f=f*i; }
System.out.println("Factorial of n = "+f);
} }
♦♦4 program to find number is palindrom or not♦♦
class palindrom
{
public static void main(String[]s)
{
int a,b,c=0,d;
a=Integer.parseInt(s[0]);
d=a;
do
{ b=a%10;
c=c*10+b;
a=a/10; }
while(a>0);
if(d==c)
System.out.println("number is palindrom "+d);
else System.out.println("number is not palindrom "+d); } }

5. ♦♦5 program to find out no.is Armstrong or not ♦♦
class armstrong
{
public static void main(String[]s)
{
int a,b,c=0,d;
a=Integer.parseInt(s[0]);
{
d=a;
do
{ b=a%10;
c=c+b*b*b;
a=a/10; }
while(a>0);
if(d==c)
System.out.println("number is armstrong "+d);
else System.out.println("number is not armstrong "+d); } } }
♦♦6 program to find out even & odd number ♦♦
class number
{
public static void main(String[]s)
{
int a,b;
a=Integer.parseInt(s[0]);
b=Integer.parseInt(s[1]);
for(int i=a;i<=b;i++)
{ if(i%2==0)
System.out.println("Number is even = "+i);

6. else System.out.println("Number is odd = "+i); } } }
♦♦7 program to print the table from “x” to “y”♦♦
class table
{
public static void main(String []s)
{
int a,b;
a=Integer.parseInt(s[0]);
b=Integer.parseInt(s[1]);
if(a<=b)
{
for(int i=a;i<=b;i++)
{
for(int j=1;j<=10;j++)
{
System.out.print(j*i+" ");
}
System.out.println(" ");
}}
else
{
for(int i=b;i<=a;i++)
{
for(int j=1;j<=10;j++)
{
System.out.print(j*i+" ");
}
System.out.println(" ");
}
}
}
}

7. ♦♦ 8 program to print no. in various format ♦♦
class print
{
public static void main(String[]s)
{
int a,b;
a=Integer.parseInt(s[0]);
b=Integer.parseInt(s[1]);
for(int i=a;i<=b;i++)
{
for(int j=a;j<=i;j++)
{
System.out.print(" "+j);
}
System.out.println(" ");
} System.out.println(" ");
for(int i=b;i>=a;i--)
{
for(int j=a;j<=i;j++)
{
System.out.print(" "+j);
}
System.out.println(" ");
}
System.out.println(" ");
for(int i=b;i>=a;i--)
{
for(int j=b;j>=i;j--)
{
System.out.print(" "+j);

8. }
System.out.println(" ");
}
System.out.println(" ");
for(int i=a;i<=b;i++)
{
for(int j=b;j>=i;j--)
{
System.out.print(" "+j);
}
System.out.println(" ");
}
System.out.println(" ");
for(int i=a;i<=b;i++)
{
for(int j=i;j>=a;j--)
{
System.out.print(" "+j);
}
System.out.println(" ");
} System.out.println(" ");
for(int i=b;i>=a;i--)
{
for(int j=i;j>=a;j--)
{
System.out.print(" "+j);
} System.out.println(" ");
} } }

9. ♦♦ 9 program Of Overriding ♦♦
class x
{
public void test(int a,int b )
{
int c= a + b ;
System.out.println("from class x sum ="+c);
}
}
class y extends x
{
public void test(int a,int b )

10. {
int c= a * b ;
System.out.println("from class y multiplication ="+c);
}
}
class overriding
{
public static void main(String [ ]s)
{
int a,b;
a=Integer.parseInt(s[0]);
b=Integer.parseInt(s[1]);
y obj=new y( );
obj.test(a,b);
}
}
♦♦ 10 program Of Overloading ♦♦
class x
{
public void test(int a, int b )
{
int c = a * b ;
System.out.println("multiplication of number = "+c);
} }
class y
{
public void test(int a, int b, int d )

11. {
int c= a + b + d ;
System.out.println("sum of given number = "+c);
} }
class overloading
{
public static void main (String [ ] s)
{
int a=Integer.parseInt(s[0]);
int b=Integer.parseInt(s[1]);
int d=Integer.parseInt(s[2]);
x obj = new x( );
obj.test(a ,b );
y obj1 = new y( );
obj1.test(a ,b ,d );
} }
♦♦11 Communication of class by creating object♦♦
class A
{
public void show( )
{
System.out.println("welcome from A");
}
}
class B
{
public void show1( )

12. {
A obj=new A( );
obj.show( );
}
}
class C
{
public static void main (String [ ] s)
{
B obj=new B( );
obj.show1( );
}
}
♦♦ 12 Communication of class by inheritance ♦♦
class A
{
public void show( )
{
System.out.println("welcome from A");
} }
class B extends A
{
public void show1( )
{
System.out.println("welcome from B");
} }

13. class D
{
public static void main (String [ ] s)
{
B obj = new B( );
obj.show( );
} }
♦ 13 Area of circle & rectangle using object ♦
class circle
{
public void area_c(int r )
{
int ar;
ar=r*r*22/7;
System.out.println("Area of circle= "+ar);
}
}
class rect
{

14. public void area_rec(int le, int br )
{
int ar;
ar=le*br;
System.out.println("Area of rectangle= "+ar);
}
}
class area
{
public static void main (String [ ] s)
{
int r=Integer.parseInt(s[0]);
int le=Integer.parseInt(s[1]);
int br=Integer.parseInt(s[2]);
circle obj=new circle( );
obj.area_c(r );
rect obj1=new rect( );
obj1.area_rec(le, br );
}
}
♦♦14 use of abstract class ♦♦
abstract class test
{
abstract public void show( );
{ }
}
class help extends test
{
public void show( )
{
System.out.println(" from class help ");
} }

15. class take extends test
{
public void show( )
{
System.out.println(" from class take ");
} }
class give extends test
{
public void show( )
{
System.out.println(" from class give ");
} }
class abstractdemo
{
public static void main (String [ ] s)
{
help obj=new help( );
obj.show( );
take obj1=new take( );
obj1.show( );
give obj2=new give( );
obj2.show( ); } }

16. ♦♦ 15 use of package ♦♦
packagea;
public class a1
{ public void sum(inta, int b)
{ int c= a + b;
System.out.println("sum="+c); } }
packagea;
public class a5
{ public void fact(int a, int b)
{for(inti=a;i<=b;i++)
{ int f=1;
for(intj=i;j>=1;j--)
{ f=f*j; }
System.out.print("Factof "+i);
System.out.println("="+f); } } }
packagea;
public class a4
{ public void table(int a,int b)
{ for(int i=a;i<=b;i++)
{ System.out.print("tableof "+i);
System.out.print("=");
for(intj=1;j<=10;j++)
{ System.out.print(" "+j*i); }
System.out.println(" "); } } }
packagea;
public class a3
{ public void mul(int a, int b)
{ int c= a * b;
System.out.println("mul="+c); } }
packagea;
public class a2
{ public void sub(inta, int b)
{ if(a>b)
{ int c= a - b;
System.out.println("sub ="+c); }
else
{ int c= b - a;
System.out.println("sub ="+c); } } }

17. import a.*;
class cal
{ public static void main(String []s)
{ int a=Integer.parseInt(s[0]);
int b=Integer.parseInt(s[1]);
a1 obj=new a1();
obj.sum(a,b);
a2 obj1=new a2();
obj1.sub(a,b);
a3 obj3=new a3();
obj3.mul(a,b);
a4 obj4=new a4();
obj4.table(a,b);
a5 obj5=new a5();
obj5.fact(a,b); } }

18. ♦♦ 16 “try” and “catch” block ♦♦
class ab
{
public static void main(String [ ]s)
{
try
{
int i=Integer.parseInt(s[0]);
int j=Integer.parseInt(s[1]);
int k=i/j;
System.out.print("result="+k);
}
catch(Exception e)
{System.out.print(e);}
}
}

19. ♦♦17 Userthread by extending Thread class ♦♦
class abc extends Thread
{
public abc()
{
start();
}
public void run()
{
try
{
for(int i=5;i<=9;i++)
{ System.out.print("table of "+i);
System.out.print("=");
for(int j=1;j<=10;j++)
{ System.out.print(" "+j*i); }
System.out.println(" ");
sleep(500);
}
}
catch(Exception e)
{System.out.print(e);}
}
}
class test
{
public static void main (String []s)
{
try
{
abc obj=new abc();
}
catch(Exception e)
{System.out.print(e);}
} }

20. ♦♦18 multiplethread with join(); ♦♦
class sud extends Thread
{
String name;
public sud(String name)
{
this.name=name;
start();
}
public void run()
{
try
{
for(int i=0;i<5;i++)
{
System.out.println("name =" +" " +name +"=" +i);
sleep(500);
}
}
catch(Exception e)
{System.out.print(e);}
}
}
class main
{
public static void main(String []s)
{
try
{
sud one=new sud("first ");
sud sec=new sud("second");
sud third=new sud("third ");
sec.join();
one.join();
third.join();
for(int i=0;i<5;i++)
{
System.out.println("main = " +i);
}
}
catch(Exception e)
{System.out.print(e);}
}
}

22. ♦♦19 Take input until char= ’z’ in io-package ♦♦
import java.io.*;
classabc
{
public static void main(String []s)
{
char c;
try
{
BufferedReader B=new BufferedReader(new
InputStreamReader(System.in));
do
{
System.out.print("enter until z =");
c=(char)B.read();
}
while(c!= 'z');
}
catch(Exception e)
{System.out.print(e);}
}
}

23. ♦♦20 Take input until string=’off’ in io package
import java.io.*;
classabc
{
public static void main(String []s)
{
String l;
try
{
BufferedReader B=new BufferedReader(new
InputStreamReader(System.in));
do
{
l=B.readLine();
System.out.print("enter until off =");
if(l.equals ("off"))
{break;}
}
while(true);
}
catch(Exception e)
{System.out.print(e);}
}
}

24. ♦♦21 Open a file in read mode in io-package ♦♦
import java.io.*;
class file
{
public static void main(String []s)
{
try
{
FileInputStream B=new FileInputStream("sud.txt");
while (B.read()!=-1)
{
char c=(char)B.read();
System.out.print(c);
}
}
catch(Exception e)
{System.out.print(e);}
}
}

25. ♦♦22insert value in database ♦♦
importjava.sql.*;
class insert
{
public static void main(String []s)
{
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection
con=DriverManager.getConnection("Jdbc:Odbc:Contact_detail");
PreparedStatementpst=con.prepareStatement("insert into
values('abc' ,+918009000260,'abc@gmail.com')");
pst.close();
con.close();
}
catch(Exception e)
{System.out.print(e);}
}
}
♦♦23featch value from database ♦♦
importjava.sql.*;
classfeatch
{
public static void main(String []s1)
{
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection
con=DriverManager.getConnection("Jdbc:Odbc:Contact_detail");
Statement smt=con.createStatement();
ResultSetrs=smt.executeQuery("select * from emp");
while(rs.next())
{
int a=rs.getInt(1);
String s=rs.getString(2);
System.out.print(a +" " +s);
} }
catch(Exception e)
{System.out.print(e);}
}}

26. <HTML>
<from method=”get” action=”demo”>Enter the number : -
<input type="text" name="number"/><br>
<input type="submit" name="submit"/><br>
</form></html>
♦♦24Display Welcome with user Servlat♦♦
import java.io.*;
importjavax.servlet.*;
public class demo extends GenericServlet
{
publi void service(ServletRequestreq,ServletResponse res)
throws ServletException, IOexception
{
res.setContent Type("text/HTML");
PrintWriter out=res.getWriter();
for(inti=0;i<10;i++)
{
out.print("Welcome");
} } }
♦25receive data from HTML and cheak even/odd ♦
import java.io.*;
importjavax.servlet.*;
public class demo extends GenericServlet
{
publi void service(ServletRequestreq,ServletResponse res)
throws ServletException, IOexception
{
res.setContent Type("text/HTML");
PrintWriter out=res.getWriter();
int a=Interger.ParseInt(req.getParameter("number"));
if(a%2==0)

27. <html><form method="get" action="first">
Enter Name:-<input type="text" name="name"/><br><br>
Enter Password :- <input type="password" name="password"/><br><br>
<input type="submit" name="submit"/><br>
</form></html>
import java.io.*;
importjavax.servlet.*;
importjavax.servlet.http.*;
public class firstextends GenericServlet
{
public void service(ServletRequestreq,ServletResponseres) throws
ServletException, IoException
{
RequestDispatcherrd=req.getRequestDispatcher("home")
res.setContentType("text/HTML");
PrintWriter out=res.getWriter();
String name=(String)req.getParameter("name");
String password=(String)req.getParameter("password");
if (name.equals("sudeep") &&password.equals("abc123"))
rd.forword(req, res)
out.print("Number is even = "+a);
else
out.print("Number is odd = "+a);
}}
♦♦ 26passing values between servlet ♦♦
“login.html”
“first.java”

28. import java.io.*;
importjavax.servlet.*;
importjavax.servlet.http.*;
public class firstextends GenericServlet
{
publi void service(ServletRequestreq,ServletResponseres) throws
ServletException, IOexception
{
res.setContentType("text/HTML");
PrintWriter out=res.getWriter();
String n=(String)req.getAttribute("name");
String p=(String)req.getAttribute("password");
out.print("name="+n +" " +"password="+p));
}
}
“home.java”