Introduction to Java Networking Lecturer: Kalamullah Ramli Electrical Engineering Dept. University of Indonesia Session-6

Slide - 2 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Networking Topics  Network Protocols in Java:  TCP  UDP  Multicast  Threaded and Non-Threaded examples  Remote Method Invocation (RMI)

Slide - 3 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng A Short History of Java Networking (1/3)  The Dark Ages: C/C++ Networking and the Need for Change  Before Java, simple network connectivity required lots of code.  C/C++ provided many, many choices/options for networking  Good for C programmers.  Most programmers did not use all these options.

Slide - 4 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng A Short History of Java Networking (2/3)  Java 1.0  Basic networking capability with high level abstraction of URL handlers.  Low level choices were missing (e.g., connection timeouts.)  Raw socket classes were final--java.net.Socket and java.net.ServerSocket could not be extended.  “One shot” implementations with java.net.SocketImpl allowed only one implementation in each VM.

Slide - 5 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng A Short History of Java Networking (3/3)  JDK 1.1 (the big leap)  Added four common socket options.  Allowed raw data manipulations within high-level abstractions.  Removed final designations.  Added multicast connections (previously limited to LAN and/or external native calls).  JDK 1.2 (a second big leap)  Addition of fine-grained Java Security Model.  ability to control processes/connections/ports with very fine granular control over details.  Added functionality to APIs.

Slide - 6 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Competing Networking Models: OSI vs. Internet Whose Kung Fu is Better?  Two competing models are used to describe networking  Open Systems Interconnection (OSI) architecture  Internet Architecture  Open Systems Interconnection Standard  partitions network connectivity into seven layers.  published by OSI and International Telecommunications Union (ITU) in series of “X dot” standards: X.25, X.400, etc.  Internet Architecture Standard  also known as “TCP/IP architecture” after its two key protocols  evolved from packet-switched ARPANET of DoD  Internet Engineering Task Force (IETF) maintenance.

Slide - 7 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng OSI in Action

Slide - 8 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Internet Architecture Model

Slide - 9 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Internet Architecture Model (1/2)

Slide - 10 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Internet Architecture Model (2/2)

Slide - 11 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Network Protocols in Java (1/3)

Slide - 12 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Basic Terminology: IP Address (2/3)

Slide - 13 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Basic Terminology: Ports (3/3)

Slide - 14 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng The java.net.* Package

Slide - 15 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Address Representations

Slide - 16 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Converting IP Numbers to String

Slide - 17 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Other InetAddress Services   public boolean isMulticastAddress();   static InetAddress[] getAllByName(String host); Determines all the IP addresses of a host, given the host's name.   static InetAddress getByName(String host); Determines the IP address of a host, given the host's name.

Slide - 18 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Sockets: Constructors

Slide - 19 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Sockets: Simple Usage

Slide - 20 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng TCP/UDP Connections Distinguished

Slide - 21 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Reading and Writing from Sockets (1/2)   Sockets in Java are full duplex--meaning that they can both send and receive information.   A good example of this feature is an echo client. The echo service listens to Port 7, and simply returns or ‘echoes back’ all information received from the client.   An echo client, therefore, has to be able to send and receive over the same socket.   Let’s look at an echo client written by Sun....

Slide - 22 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng Reading and Writing from Sockets (2/2)

Slide - 23 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng ServerSockets (1/3)

Slide - 24 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng ServerSockets (2/3)

Slide - 25 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng ServerSockets (3/3)

Slide - 26 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng

Slide - 27 OOP Lecture 2004 Dr. –Ing. Ir. Kalamullah Ramli, M.Eng The End QUESTIONS & COMMENTS ?