I'm working on a project which uses JAAS and unfortunately for me Tomcat requires a file to be put in a META-INF folder in the root of the war
app.war
|__META-INF
| |___context.xml
...
I think that it's already weird since the default META-INF location for WAR's is in the classes folders.
app.war
|__WEB-INF
| |__classes
| |__META-INF
...
So I'm using Maven, which states that anything in src/main/resources/META-INF will be copied to the appropriate place, which it does. The weird thing is that it is also creating a META-INF folder in the root of the file structure leaving me with 2 META-INF folders.
Project Structure
app
|__src/main/java
|__src/main/resources
| |__META-INF
| |__context.xml
...
After mvn package
app
|__META-INF [1]
|__WEB-INF
| |__classes
| |__META-INF [2]
| |__context.xml
...
So, if the war standard states that META-INF should be under classes folder, as in #2, why maven war creates the #1 folder. And is there a way to make it copy files into that folder instead of #2?
Regards
It shouldn't be at the project root, but directly under the source folder. At runtime, the persistence. xml file is searched in the classpath, under META-INF. So if you want the META-INF folder to be put at the top of the compiled package tree, you need to put it at the top of the source tree.
The META-INF folder is the home for the MANIFEST. MF file. This file contains meta data about the contents of the JAR. For example, there is an entry called Main-Class that specifies the name of the Java class with the static main() for executable JAR files.
The META-INF directory The manifest file that is used to define extension and package related data. This file is generated by the new "-i" option of the jar tool, which contains location information for packages defined in an application or extension.
META-INF is intended to contain the MANIFEST. MF file and the services subdirectory related to the ServiceLoader class, but other frameworks, including Spring, use it as well.
So I found this:
Two Meta-Inf folders - normal structure?
which states that having 2 META-INF folders is not a problem. Digging a little I found:
JAR File Specification
which states about the META-INF folder:
A JAR file is essentially a zip file that contains an optional META-INF directory. ...The META-INF directory, if it exists, is used to store package and extension configuration data, including security, versioning, extension and services.
and this:
JSR-000315 JavaTM Servlet 3.0
which, on section 10.6, states about the WAR file structure:
When packaged into such a form, a META-INF directory will be present which contains information useful to Java archive tools. This directory must not be directly served as content by the container in response to a Web client’s request, though its contents are visible to servlet code via the getResource and getResourceAsStream calls on the ServletContext. Also, any requests to access the resources in META-INF directory must be returned with a SC_NOT_FOUND(404) response.
So from the WAR spec the right place is WEB-INF/classes/META-INF. Yet, since war is a special jar file, it makes sense to have /META-INF as a point for extensions. One can see such different uses in JPA persistence.xml vs. Tomcat context.xml files: the former should be placed in WEB-INF/classes/META-INF while the latter in /META-INF.
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