content/system-properties.mdtext

Title: System Properties

<a name="SystemProperties-Overridingopenejb.xml"></a>

You can find a list of properties [here](properties-listing.html). But read on to understand how these can be used.

#  Overriding openejb.xml

Anything in the openejb.xml file can be overridden via system properties of
the format: 


  `-D<id>.<property-name>=<property-value>`

..where id is the value in the config file for example: 


    <Connector id="mysql"> 
        JdbcDriver com.mysql.jdbc.Driver 
        JdbcUrl jdbc:mysql://localhost/test 
        UserName test 
    </Connector> 


Could be overridden as follows via system properties on the command line: 

> ./bin/openejb start -Dmysql.JdbcDriver=com.mysql.jdbc.Driver
> -Dmysql.JdbcUrl=jdbc:mysql://localhost/test -Dmysql.UserName=test

<a name="SystemProperties-OverridingServerServices"></a>

#  Overriding Server Services

Any server service installed into OpenEJB can be overridden in the same
fashion as things in the openejb.xml file.  

For example, when OpenEJB starts it prints out the following:


      ** Starting Services **
      NAME		       IP	       PORT  
      httpejbd	       0.0.0.0	       4204  
      telnet	       0.0.0.0	       4202  
      ejbd		       0.0.0.0	       4201  
      hsql		       0.0.0.0	       9001  
      activemq	       127.0.0.1       4206  
      derbynet	       0.0.0.0	       4205  
      admin thread	       0.0.0.0	       4200  


Each of those has the same standard xinet.d-like properties which can also
be configured as such:


  `-D<id>.<property-name>=<property-value>`


... where 'id' is the name of the server service and 'property-name' is one
of the following: bind, port, threads, disabled, only_from.

So to set the address and port the ejbd service will bind to, simply
specify this on the command line:

    ./bin/openejb start -Dejbd.bind=192.168.1.12 -Dejbd.port=9988