• What is server

  In most common use, a server is a physical computer (a computer hardware system) dedicated to run one or more services (as a host), to serve the needs of the users of other computers on the network. Depending on the computing service that it offers it could be a database server, file server, mail server, print server, web server, gaming server, or some other kind of server. In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients". The clients either run on the same computer or connect through the network. In the context of Internet Protocol (IP) networking, a server is a program that operates as a socket listener. Servers often provide essential services across a network, either to private users inside a large organization or to public users via the Internet.

• Usage

  The term server is used quite broadly in information technology. Despite the many server-branded products available (such as server versions of hardware, software or operating systems), in theory any computerised process that shares a resource to one or more client processes is a server. To illustrate this, take the common example of file sharing. While the existence of files on a machine does not classify it as a server, the mechanism which shares these files to clients by the operating system is the server. Similarly, consider a web server application (such as the multiplatform "Apache HTTP Server"). This web server software can be run on any capable computer. For example, while a laptop or personal computer is not typically known as a server, they can in these situations fulfill the role of one, and hence be labelled as one. It is, in this case, the machine's role that places it in the category of server. In the hardware sense, the word server typically designates computer models intended for hosting software applications under the heavy demand of a network environment. In this client-server configuration one or more machines, either a computer or a computer appliance, share information with each other with one acting as a host for the other[s]. While nearly any personal computer is capable of acting as a network server, a dedicated server will contain features making it more suitable for production environments. These features may include a faster CPU, increased high-performance RAM, and increased storage capacity in the form of a larger or multiple hard drives. Servers also typically have reliability, availability and serviceability (RAS) and fault tolerance features, such as redundancy in power supplies, storage (as in RAID), and network connections. Servers became common in the early 1990s as businesses increasingly began using personal computers to provide services formerly hosted on larger mainframes or minicomputers. Early file servers housed multiple CD-ROM drives, which were used to host large database applications.[citation needed] Between the 1990s and 2000s an increase in the use of dedicated hardware saw the advent of self-contained server appliances. One well-known product is the Google Search Appliance, a unit that combines hardware and software in an out-of-the-box packaging. Simpler examples of such appliances include switches, routers, gateways, and print server, all of which are available in a near plug-and-play configuration. Modern operating systems such as Microsoft Windows or Linux distributions rightfully seem to be designed with a client-server architecture in mind. These operating systems attempt to abstract hardware, allowing a wide variety of software to work with components of the computer. In a sense, the operating system can be seen as serving hardware to the software, which in all but low-level programming languages must interact using an API. These operating systems may be able to run programs in the background called either services or daemons. Such programs, such as the aforementioned Apache HTTP Server software, may wait in a sleep state for their necessity to become apparent. Since any software that provides services can be called a server, modern personal computers can be seen as a forest of servers and clients operating in parallel. The Internet itself is also a forest of servers and clients. Merely requesting a web page from a few kilometers away involves satisfying a stack of protocols that involve many examples of hardware and software servers. The least of these are the routers, modems, domain name servers, and various other servers necessary to provide us the world wide web.

• Types of servers

  In a general network environment the following types of servers may be found. Application server, a server dedicated to running certain software applications Catalog server, a central search point for information across a distributed network Communications server, carrier-grade computing platform for communications networks Database server, provides database services to other computer programs or computers Fax server, provides fax services for clients File server, provides remote access to files Game server, a server that video game clients connect to in order to play online together Home server, a server for the home Name server or DNS Print server, provides printer services Proxy server, acts as an intermediary for requests from clients seeking resources from other servers Sound server, provides multimedia broadcasting, streaming. Standalone server, an emulator for client-server (web-based) programs Web server, a server that HTTP clients connect to in order to send commands and receive responses along with data contents

OC4J ReadMe

=========================================

Oracle Containers for J2EE 10g (10.1.3.1)

=========================================



OC4J Zip Distribution ReadMe



Contents

--------



    * Introduction

    * Prerequisites

    * Extracting OC4J

    * OC4J Command Script

    * First Time Initialization

    * Starting and Stopping OC4J

    * Directly Starting and Stopping OC4J

    * Testing the OC4J Installation

    * Using Application Server Control

    * Using the admin_client.jar Command Line Utility

    * Example usages of admin_client.jar



Introduction

------------



The Oracle Containers for J2EE (OC4J) zip distribution provides

a complete J2EE 1.4 server environment distributed as a simple zip file.



The OC4J zip distribution includes an HTTP/S server, all of the required J2EE

1.4 APIs and services, a complete EJB 3.0 and JPA implementation,

Oracle TopLink, extensive Web Services capabilities and the browser-based

Application Server Control Console management interface to configure the server

and deploy applications.





Prerequisites

--------------



In order to use the OC4J zip distribution, a Java2 Standard

Edition (J2SE) SDK version 5.0 (or 1.4.2) must be installed on the host machine.





Extracting OC4J

---------------



Extract the oc4j_extended.zip file using  any archive utility which handles zip

files, including the jar utility in the J2SE.



The following directory structure will be created:



    

        /ant

        /bin

        /diagnostics

        /j2ee

        /javacache

        /javavm

        /jdbc

        /jlib

        /lib

        /opmn

        /rdbms

        /sqlj

        /toplink

        /webservices

        /xqs



Where  is the directory into which the oc4j_extended.zip file was

extracted.





OC4J Command Script

-------------------



The OC4J zip distribution provides a script that can be used to start and stop a

local OC4J instance. The oc4j script is located in the /bin

directory.



    Usage: oc4j [Options]



The commands supported by the OC4J command script are:



    Usage: oc4j [Options]

    Options:



    -start                                           : start OC4J

    -shutdown -port  -password  : stop OC4J

    -version                                         : display the version

    -help                                            : display this message



Before using the OC4J command script, the following environment variables must

be set:



    ORACLE_HOME : directory where oc4j_extended.zip was extracted.

    JAVA_HOME   : location of the J2SE SDK to be used.



For example, if oc4j_extended.zip was extracted to /java/oc4j-10131 and the

J2SDK was installed in /java/j2se15 then JAVA_HOME and ORACLE_HOME would be set

as:



    JAVA_HOME=/java/j2se15

    ORACLE_HOME=/java/oc4j-10131





First Time Initialization

-------------------------



There are no specific tasks that need to be performed to ready the new OC4J

instance for use.  The new OC4J instance can be used immediately after the unzip

operation has completed.



** Note: on the first use of OC4J, you will be prompted to enter a password for

the OC4J administrator account. The username for this account defaults to

"oc4jadmin".



Change to the /bin  directory, and issue the following command:



    > cd /bin

    > oc4j -start



    Starting OC4J from /java/oc4j-10131/j2ee/home ...



    ... 



    06/08/23 13:57:17 Set OC4J administrator's password (password text will not

    be displayed as it is entered)

    Enter password: ******

    Confirm password: ********

    The password for OC4J administrator "oc4jadmin" has been set.

    06/08/23 13:57:17  The OC4J administrator "oc4jadmin" account is activated.

    06/08/23 13:57:22 The OC4J administrator "oc4jadmin" account is activated.

    06/08/23 13:57:31 Oracle Containers for J2EE 10g (10.1.3.1.0) initialized



OC4J is configured with a set of defaults that includes a Web site from which

deployed applications and the management console can be accessed. These are

provided so OC4J can be started and used immediately without requiring

additional configuration tasks to be performed.





Starting and Stopping OC4J

--------------------------



The OC4J command script can be used to start and stop OC4J processes.



Start OC4J using the command script as follows:



    >cd /bin

    >oc4j -start



    Starting OC4J from /java/oc4j-10131/j2ee/home ...

    06/08/23 14:00:38 Oracle Containers for J2EE 10g (10.1.3.1.0)  initialized





Stop OC4J using the command script as follows:



    >cd /bin

    >oc4j -shutdown -port 23791 -password welcome



    Shutdown OC4J instance...



    Where :



    -port specifies the ORMI port in use with the local OC4J process.



    -password specifies the administration password entered as

     described in the "Basic Installation" section of this document.





Directly Starting and Stopping OC4J

-----------------------------------



In addition to the OC4J command script, it possible to directly start OC4J using

oc4j.jar on the command line.



Directly start OC4J server by changing to the J2EE_HOME directory and issuing

one of the following commands:



Option 1: Start OC4J using the default configuration files, which are located in

the j2ee/home/config directory.



    > cd /j2ee/home

    > java -jar oc4j.jar



Option 2: Start OC4J using a customized server.xml OC4J configuration file

located in a non-default directory (/mypath).



    > cd /j2ee/home

    > java -jar oc4j.jar -config /mypath/server.xml



The server outputs an initialization string with the version number when it is

ready to accept requests. For example:



    Oracle Containers for J2EE 10g (10.1.3.1.0) initialized



Stop OC4J using one of these methods:



- Use the "stop" button from within Application Server Control



- Use the shutdown command in the admin_client.jar command-line utility



- Press ^c (Ctrl+c) in the window where the process was started



- Use the process termination command (for example

"kill" on Unix/Linux) for the operating system in use.OC4J will indicate on the

console window that it is shutting down when it receives a shutdown signal.





Testing the OC4J Installation

-----------------------------



Test the installation by starting the OC4J instance and accessing the welcome

page from a Web browser.



    http://:8888



Where  is the name of the server on which OC4J is running. The OC4J

welcome page will be displayed.



On the right hand side of the welcome page is a portlet with links to enable the

testing of the JSP and Servlet environments using standard examples.



If the default port number in the default-web-site.xml file has been changed,

access the Web server using :



    http://:



Where  is the value specified in the "port" attribute of the

 element in the file.





Using Application Server Control Console

----------------------------------------



The OC4J zip distribution contains the JMX-based Application

Server Control Console, which enables you to perform server configuration tasks

as well as deploy and manage applications.



Application Server Control Console provides:



    + JSR-77 management and JSR-88 based deployment support

    + Extensive deployment support, including a comprehensive deployment

      plan editor

    + Configuration and management support for Web Services

    + An MBean browser for directly accessing OC4J System MBeans as well as

      application-specific MBeans

    + A JNDI browser



Application Server Control Console is configured to be auto-deployed when the

OC4J instance is started for the first time.



Application Server Control Console can be accessed using the URL:



    http://:8888/em



To logon to Application Server Control Console use the "oc4jadmin" username and

the password you set during the first initialization of OC4J.



Using the admin_client.jar Command-Line Utility

-----------------------------------------------



OC4J provides a command-line utility, admin_client.jar,that can be used to

perform operations on a running OC4J instance. Among other things, you can use

admin_client.jar to restart and stop OC4J, deploy applications, and configure

various resources. The admin_client.jar utility can operate

against OC4J instances running in a standalone mode or when in an Oracle

Application Server environment.



Note: the admin_client.jar utility is the replacement utility of the earlier

admin.jar.  It operates using the OC4J MBeans and the J2EE Deployment API. It

has a similar usage model to admin.jar but provides more comprehensive support

for deployment operations.



The admin_client.jar utility uses ORMI to connect to a running OC4J process. This

means OC4J must be started before using the utility. Note that OC4J can't be

started using admin_client.jar.



The admin_client.jar utility is exercised using the following command:



    > java -jar admin_client.jar   

      



Usage Notes:



   - The deployment URI specifies the target OC4J on which to perform the

     specified command.  A deployment URI can be one of three forms



     OC4J Standalone:



         deployer:oc4j:hostname:ormi_port



         deployer:oc4j:localhost:23791



         deployer:oc4j:localhost (defaults to 23791)



     Oracle Application Server - Single Instance:



         deployer:oc4j:opmn://opmn_host:opmn_port/oc4jInstanceName



         deployer:oc4j:opmn://localhost:6003/home



         deployer:oc4j:opmn://localhost/home (defaults to 6003)



     Oracle Application Server - Group:



         deployer:cluster:opmn://opmn_host:opmn_port/groupName



         deployer:cluster:opmn://localhost/Colors



   - The admin_user should be specified as "oc4jadmin" by default.



   - The admin_pwd is the "oc4jadmin" account password you configured

     during the first time initialization of the OC4J instance.



Use the -help option see all of the available admin_client.jar commands.



    > java -jar admin_client.jar -help



Use the -usage  option to see detailed information for a specific

command.



    > java -jar admin_client.jar -usage 



    > java -jar admin_client.jar -usage deploy





Example usages of admin_client.jar

----------------------------------



Note: all these examples are executed from within the /j2ee/home

directory.



To restart OC4J:



    > java -jar admin_client.jar deployer:oc4j:localhost oc4jadmin 

      -restart



To shutdown OC4J:



    > java -jar admin_client.jar deployer:oc4j:localhost oc4jadmin 

      -shutdown



To deploy a WAR:



    >java -jar admin_client.jar deployer:oc4j:localhost oc4jadmin 

     -deploy

     -file 

     -deploymentName 

     -contextRoot