Class GnuConfiguration

   CONFIG              ::= APP_OR_OTHER_ENTRY+
   APP_OR_OTHER_ENTRY  ::= APP_NAME_OR_OTHER JAAS_CONFIG_BLOCK
   APP_NAME_OR_OTHER   ::= APP_NAME
                         | 'other'
   JAAS_CONFIG_BLOCK   ::= '{' (LOGIN_MODULE_ENTRY ';')+ '}' ';'
   LOGIN_MODULE_ENTRY  ::= MODULE_CLASS FLAG MODULE_OPTION* ';'
   FLAG                ::= 'required'
                         | 'requisite'
                         | 'sufficient'
                         | 'optional'
   MODULE_OPTION       ::= PARAM_NAME '=' PARAM_VALUE

   APP_NAME     ::= JAVA_IDENTIFIER
   MODULE_CLASS ::= JAVA_IDENTIFIER ('.' JAVA_IDENTIFIER)*
   PARAM_NAME   ::= STRING
   PARAM_VALUE  ::= '"' STRING '"' | ''' STRING ''' | STRING
 

This implementation will specifically attempt to process one or more Login Configuration files in the following locations, and when found parse them and merge their contents. The locations, and the order in which they are investigated, follows:

1. If the following Security properties: java.security.auth.login.config.url.N, where N is a digit, from 1 to an arbitrary number, are defined, then the value of each of those properties will be considered as a JAAS Login Configuration file written in the default syntax. This implementation will attempt parsing all such files.

   It is worth noting the following:
2. The GNU Classpath security file, named classpath.security, where all Security properties are encoded, is usually located in /usr/local/classpath/lib/security folder.
3. The numbers used in the properties java.security.auth.login.config.url.N MUST be sequential, with no breaks in-between.
4. If the System property named java.security.auth.login.config is not null or empty, its contents are then interpreted as a URL to a JAAS Login Configuration file written in the default syntax.

   If this System property is defined, and the file it refers to was parsed correctly, then no other location will be inspected.

5. If a file named .java.login.config or java.login.config (in that order) is found in the location referenced by the value of the System property user.home, then that file is parsed as a JAAS Login Configuration written in the default syntax.
6. If none of the above resulted in a correctly parsed JAAS Login Configuration file, then this implementation will install a Null Configuration which basically does not recognize any Application.