What does Tool/Bundle-Name/Export-Package etc. mean in a jar manifest

Question

I'm looking at the manifest.mf for some apache libraries. While I can guess what Export-Package means, I can't find any documentation for these attributes ? Could anyone point me in the right direction. Here.s an example:

Manifest-Version: 1.0
Created-By: 1.6.0_07 (Sun Microsystems Inc.)
Built-By: pemben
Implementation-Title: Commons BeanUtils
Implementation-Vendor: The Apache Software Foundation
Implementation-Vendor-Id: org.apache
Implementation-Version: 1.8.2
Specification-Title: Commons BeanUtils
Specification-Vendor: The Apache Software Foundation
Specification-Version: 1.8.2
Export-Package: org.apache.commons.beanutils.locale.converters;
Private-Package: org.apache.commons.collections;version="1.8.2"
Ignore-Package: org.apache.commons.collections
Tool: Bnd-0.0.238
Bundle-Name: Commons BeanUtils
Bundle-Vendor: The Apache Software Foundation
Bundle-Version: 1.8.2
Bnd-LastModified: 1257775355133
Bundle-ManifestVersion: 2
Bundle-License: http://www.apache.org/licenses/LICENSE-2.0.txt
Bundle-Description: BeanUtils provides an easy-to-use but flexible wra
 pper around reflection and introspection.
Import-Package: org.apache.commons.beanutils;version="1.8.2"
Bundle-SymbolicName: org.apache.commons.beanutils
Bundle-DocURL: http://commons.apache.org/beanutils/

Answer 1

The Bundle attributes define info wrt. OSGi bundles . An OSGi bundle is simply a .jar file that also defines (via the attributes) what it exports, and what its dependencies are (including versions). Note that the .jar file can be used as a standard .jar file - the bundle information is only used in an OSGi container.

This JavaWorld article is a good introduction.

Answer 2

This is OSGi . Eclipse uses it, also nutch.

Answer 3

From the Export-Package filed, I'd guess you are looking at an OSGi Bundle .

Check the Wikipedia article or the OSGi homepage for details.

Answer 4

If you want really good explanations for the meanings of OSGi Manifest entries, I strongly suggest you read the specification . It is not very long and will explain in good detail all you want to know. Also, keep in mind that the Manifest.mf file is not specific to OSGi; other Java libraries also make use of it. As such, not all the entries you see above are defined by the OSGi specification, such as 'Tool', and 'Bnd-LastModified', which were added by the Bnd utility .