WebSockets

Question 1

Network connection

Answer 1

A relationship between two machines, where two pieces of software know about each other

Question 2

Socket declaration

Answer 2

Socket chatsocket = new Socket(“196.164.1.103”, 5000);

Question 3

Socket connection

Answer 3

Two machines have information about each other, including network location (IP address) and TCP port

Question 4

TCP port

Answer 4

A 16-bit numbers that identifies a specific program on the server

Question 5

What happen without port numbers?

Answer 5

The server would have no way of knowing which application a client wanted to connect to

Question 6

Why use TCP after 1024?

Answer 6

Because 0 through 1023 are reserved for the well-known services

Question 7

How do you know the port number of the server program you want to talk to?

Answer 7

You need to find out from whoever is deploying the service. Ask him. Or her. Typically, if someone writes a network service and wants others to write clients for it, they’ll publish the IP address, port number, and protocol for the service

Question 8

Can there ever be more than one program running on a single port? In other words, can two applications on the same server have the same port number?

Answer 8

No! You will get BindException. To bind a program to a port just means starting up a server application and telling it to run on a particular port.

Question 9

How do you get messages from the server?

Answer 9

When you set up the networking make an input stream as well (probably a BufferedReader). Then read messages using readLine()

Question 10

Thread

Answer 10

A thread is a separate ‘thread of execution’. In other words, a separate call stack. A thread is a Java class that represents a thread.

Question 11

Runnable

Answer 11

Runnable is to a Thread what a job is to a worker. A Runnable is the job a thread is supposed to run