Using a security manager, the System Administrator can restrict how an application cooperates with other applications running in the same virtual machine (VM) or elsewhere on the same machine. When you run under a security manager, you can restrict the following:

• Backups: You control where the engine writes and reads database backup files.
• Imports and exports: You control where the engine imports data from and where it exports data to.
• Jar files: You control where the engine obtains jar files of customer-coded functions and procedures.
• Sockets: You control what machines can connect to the server and What machines the server can connect to.

To take advantage of these powerful controls, first customize a copy of the security policy template. You will find a template security policy in the distribution at demo/templates/server.policy.

shows this basic policy. It grants permissions to both the derby.jar and derbynet.jar codebases. To run in embedded mode, you must grant permissions to derby.jar. To run the Network Server, you must grant permissions to both derby.jar and derbynet.jar.

shows a sample customized policy file.

To customize the file, make the following edits:

• URLs: Replace the ${derby.install.url} variables with a URL pointing to the directory that holds the jar files. For example: file:///Users/me/javadb/lib/
• System home: Look for instances of the string ${derby.system.home}. Replace them with the name of the directory that holds your derby.properties file.
• Tracing: Grant the power to manage a directory tree that will hold server trace information. Look for the ${derby.drda.traceDirectory} variable and replace it with the directory where the server should write its diagnostic traces. For more information on tracing, see "Controlling tracing by using the trace facility" in the .
• Backups/imports/jars: Look for the first instance of the string <<ALL FILES>>. Make two more copies of this line so that there are three copies of this line in the file. On the first line, replace <<ALL FILES>> with the directory tree that you will use for holding database backups. For example: /Users/me/backups

  Similarly, on the second line, replace <<ALL FILES>> with the directory tree which you will use for staging imported/exported data. On the third line, replace <<ALL FILES>> with the directory tree that holds the jar files of functions and procedures that you will load into databases. For the detailed syntax of these lines, see the API documentation for java.io.FilePermission.

• Sysinfo: The sysinfo logic appears redundantly in several jar files: derby.jar derbynet.jar derbyclient.jar derbytools.jar

  If you want to run the sysinfo command, you will need to grant permissions to the first of these jar files that appears in your classpath.

  If you are running by using the command java -jar derbyrun.jar, the first relevant jar file in the classpath is derby.jar. The template policy file grants these permissions to derbynet.jar. Note that the template policy file grants sysinfo the privilege to read all files in the system. You can restrict this to just the directory that contains the jar files wired into your classpath.

• Sockets: The template policy file accepts connection requests from all hosts. You may want to restrict the template file's java.net.SocketPermission to connections from a particular subdomain. For details, see the API documentation for java.net.SocketPermission. In addition, if you are using LDAP authentication, then you must grant derby.jar the privilege to connect to the LDAP server.

This manual does not describe the Java security manager in depth. For more information, see . In particular, you may want to read the Security Architecture paper () and the Default Policy Implementation and Policy File Syntax information ().