The virtual server access-log configuration (subsystem xmlns="urn:jboss:domain:web:1.4") requires that the prefix attribute is present.

If the configuration is like this:

<access-log pattern="%t-[%a] %s %r@%p %b bytes %Ts"/>
... the server creates a file named "false2013-05-13"

Only when the attribute prefix="access_log." is added to the configuration, is the file nicely created like "access_log.2013-05-13".

According to the jboss-as-web_1_4.xsd file it shouldn't be required to provide the prefix attribute, as there is a default value already supplied:

<xs:complexType name="http-access-logType">
<xs:sequence>
<xs:element name="directory" type="directoryType" />
</xs:sequence>
<xs:attribute name="pattern" default="common" />
<xs:attribute name="resolve-hosts" default="false" type="xs:boolean" />
<xs:attribute name="extended" default="false" type="xs:boolean" />
<xs:attribute name="prefix" default="access_log." />
<xs:attribute name="rotate" default="true" type="xs:boolean" />
</xs:complexType>