Chat application using Socket programming in JAVA

For Source Code Click here - http://www.dreamscoder.com/viewprogram.php?id=83

this keyword in Java

Here is given the usage of this keyword.

this keyword can be used to refer current class instance variable.

this() can be used to invoke current class constructor.

this keyword can be used to invoke current class method (implicitly)

this can be passed as an argument in the method call.

this can be passed as argument in the constructor call.

this keyword can also be used to return the current class instance.

From - www.DreamsCoder.com

Star Pattern Program in C

/*Star Pattern Program in C

Author - Chinmay Mahajan*/

#include<stdio.h>
#include<conio.h>

void main()
{
int i,j,k,m,o,f,n;
clrscr();
printf("Enter value of n \n");
scanf("%d",&n);
k=n;
o=1;
for(i=0;i<n;i++) //for number of lines
{

for(j=0;j<k;j++) //for left spacing
{
printf("_");
}
for(m=0;m<o;m++) //for Printing *
{
printf(" *");
}

for(f=0;f<k;f++)  //for right spacing
{
printf("_");
}
printf("\n"); //new line
k--;
o++;
}//outer for
}//main

Socket Programming with File Handling

/*Client Socket program that accepts file name from Client and send it to Server, Server Side Socket reads the Content of a file and display them onto the Client Socket*/

/*Server Program (severprac.java)*/

import java.io.*;
import java.net.*;

public class serverprac
{

public static void main(String[] args) {

ServerSocket ss;
Socket client;
String nm;
try
{
ss = new ServerSocket(1212);
System.out.println("Server is Waitng For Client");
client = ss.accept();
System.out.println("Client is Connected");
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
BufferedReader br1 = new BufferedReader(new InputStreamReader(client.getInputStream()));
PrintStream ps = new PrintStream(client.getOutputStream());

String filenm = br1.readLine();

File f = new File(".");
File[] flist = f.listFiles();

for(File n:flist)
{
nm = n.getName();
if(nm.equals(filenm))
{

System.out.println("File is Present");
FileReader fr = new FileReader(nm);
BufferedReader bfr = new BufferedReader(fr);
String lne;
while(true)
{


lne = bfr.readLine();

                if (lne == null)
                break;
//System.out.println(lne);

ps.println(lne);
}
}
}


ps.close();
br1.close();
br.close();
ss.close();

}//try
catch(Exception e)
{
System.out.println(e);
}
}//main
}

/*Client Program (clientprac.java)*/

import java.io.*;
import java.net.*;

public class clientprac
{

public static void main(String[] args)
{
Socket s;
try
{
s = new Socket("127.0.0.1",1212);
System.out.println("Clent is Conneccted to the Server");

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
BufferedReader br1 = new BufferedReader(new InputStreamReader(s.getInputStream()));
PrintStream ps = new PrintStream(s.getOutputStream());
System.out.println("Enter File name");
ps.println(br.readLine());
while(br1.readLine() !=null)
System.out.println(br1.readLine());
br1.close();
ps.close();
br.close();
br1.close();
s.close();

}
catch(Exception e)
{
System.out.println(""+e);
}//catch
}//main
}

Inter - Thread communication using wait(), notify() and notify all() method in Java

/*
Write a program to illustrate  inter - thread communication using wait(), notify() and notify all() method
*/

import java.io.*;
class q
{
String msg;
boolean flag;
q()
{
flag=false;
}
synchronized void get()
{
if(flag==false)
{
try
{
wait();
}//try
catch(InterruptedException e)
{

}//catch

}
flag=false;
System.out.println("Received Message"+msg);
notify();
}
synchronized void put(String x)
{
if(flag==true)
{
try
{
wait();
}
catch(InterruptedException e)
{

}//catch

}
msg = x;
flag = true;

if(msg.equalsIgnoreCase("Good Bye"))
System.exit(0);
notify();
}
}


class sender extends Thread{
q q1;
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String s;
sender(q x)
{
q1 = x;
start();
}
public void run()
{
while(true)
{
System.out.println("Enter Message ");
try
{
s = br.readLine();
q1.put(s);
}
catch(IOException e)
{

}//catch
}//while
}//run
}

class receiver extends Thread
{
q q2;
receiver(q x)
{
q2 = x;
start();

}

public void run()
{
while(true)
{
q2.get();
}
}
}

class fourteen
{
public static void main(String args[])
{
q q4 = new q();
sender s = new sender(q4);
receiver r = new receiver(q4);
}
}

User Defined Exception Example in Java

/*
Write a class Student with attributes roll no, name, age and course. Initialize values through parameterized constructor. If age of student is not in between 15 and 21 then generate user-defined exception “Age Not Within The Range”.If name contains numbers or special symbols raise exception “Name not valid”
*/

import java.io.*;
class AgeNotWithinRangeException extends Exception
{
AgeNotWithinRangeException()
{
super();
}
}

class NameNotValidException extends Exception
{
NameNotValidException()
{
super();
}
}
class Student
{
private
int roll,age;
String name,course;

public
Student(int r,String nm,int ag,String co)
{
roll=r;
name=nm;
age=ag;
course=co;

System.out.println("Roll Number is "+roll);
System.out.println("Name is "+name);;
System.out.println("Age is "+age);
System.out.println("Course is "+course);
}

public static void main(String args[]) throws IOException
{

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
int roll,age;
String name,course;
System.out.println("Enter No. :");
roll = Integer.parseInt(br.readLine());
System.out.println("Enter Name :");
name = br.readLine();
try
{
for(int i=0;i<name.length();i++)
{
char c = name.charAt(i);

if((c<65 || c>90) && (c<97 || c>122) && (c!=32))
{
throw new NameNotValidException();
}//if
}//for
}//try
catch(NameNotValidException n)
{
System.out.println("Invalid Name"+n);
}
System.out.println("Enter Age :");
age = Integer.parseInt(br.readLine());
try
{
if(age<15 || age>21)
{
throw new AgeNotWithinRangeException();
}
}//try

catch(AgeNotWithinRangeException e)
{
System.out.println("Invalid Age"+e);
}

System.out.println("Enter Course :");
course = br.readLine();

Student s = new Student(roll,name,age,course);
}
}

Error while Creating New Android Project in Eclipse.

Problem with Eclipse while creating New Android Application 

Solution - In Eclipse go to Window - > Android SDK Manager 

Select one or more SDK Platform and Install them.

Also Update ADT plugins.

University Rankings For MS in Computer Science (CS) 2013

Rank	Universities
1	Carnegie Mellon University
2	Massachusetts Institute of Technology
3	Stanford University
4	University of California, Berkeley
5	Cornell University
6	University of Illinois, Urbana-Champaign
7	University of Washington
8	Princeton University
9	University of Texas, Austin
10	Georgia Institute of Technology
11	California Institute of Technology
12	University of Wisconsin, Madison
13	University of Michigan, Ann Arbor
14	University of California, Los Angeles
15	University of California, San Diego
16	University of Maryland, College Park
17	Columbia University
18	Harvard University
19	University of Pennsylvania
20	Brown University
21	Purdue University, West Lafayette
22	Rice University
23	University of Massachusetts, Amherst
24	University of North Carolina, Chapel Hill
25	University of Southern California
26	Yale University
27	Duke University
28	Johns Hopkins University
29	New York University
30	Ohio State University
31	Pennsylvania State University
32	Rutgers, the State University of New Jersey
33	University of California
34	University of Virginia
35	Northwestern University
36	University of California
37	University of Chicago
38	University of Minnesota
39	University of California
40	University of Colorado
41	University of Florida
42	University of Utah
43	Washington University in St. Louis
44	Dartmouth College
45	Stony Brook University
46	Virginia Tech
47	Boston University
48	North Carolina State University
49	Rensselaer Polytechnic Institute
50	Texas A&M University
51	University of Arizona
52	University of Rochester
53	Arizona State University
54	Indiana University
55	University of California
56	University of California
57	University of Pittsburgh
58	Michigan State University
59	University of Illinois
60	Vanderbilt University
61	Northeastern University
62	University at Buffalo
63	Case Western Reserve University
64	George Mason University
65	Iowa State UniversityOregon State University
66	Syracuse University
67	University of Iowa
68	University of Notre Dame
69	University of Oregon
70	University of Tennessee
71	Brandeis University
72	Naval Postgraduate School
73	Polytechnic Institute of New York University
74	Tufts University
75	University of Connecticut
76	University of Delaware
77	University of Maryland
78	Clemson University
79	College of William and Mary
80	Colorado State University
81	CUNY Graduate School and University Center
82	Florida State University
83	George Washington University
84	Oregon Health and Science University
85	University of Kansas
86	University of Nebraska
87	University of New Mexico
88	University of Texas
89	Washington State University
90	Auburn University
91	Brigham Young University
92	New Jersey Institute of Technology
93	University at Albany
94	University of Central Florida
95	University of Georgia
96	University of Kentucky
97	Worcester Polytechnic Institute
98	Drexel University
99	Georgia State University
100	Kansas State University
101	Lehigh University
102	Louisiana State University
103	Stevens Institute of Technology
104	University of Cincinnati
105	University of North Carolina
106	University of South Carolina
107	University of South Florida
108	University of Texas
109	Binghamton University
110	Colorado School of Mines
111	Illinois Institute of Technology
112	Southern Methodist University
113	Temple University
114	University of Houston
115	University of Missouri
116	University of Oklahoma
117	University of Wisconsin
118	Wayne State University
119	West Virginia University
120	Claremont Graduate University
121	Mississippi State University
122	Missouri University of Science & Technology
123	New Mexico State University
124	Texas Tech University
125	Wright State University