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uri           = scheme ":" "//" authority 1*( "/" segment )
authority     = host
host          = reg-name
reg-name      = *( unreserved / pct-encoded / sub-delims )
unreserved    = ALPHA / DIGIT / "-" / "." / "_" / "~"
sub-delims    = "!" / "$" / "&" / "'" / "(" / ")" / "*" / "+" / "," / ";" / "="
pct-encoded   = "%" HEXDIG HEXDIG

where the {authority component is used to contain the URI of the Path to the archive. Any characters not allow in a reg-name (specifically including "/" and ":") will be pct-encoded.

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archive:archive%3afile%253a%252f%252f%252ftmp%25%2fexample.war%2fWEB-INF%2flib%2fexample.jar/com/example/Main.class

URL Support

URL support is required to allow references to resources to be returned by a ClassLoader or ServletContext. To enable Path URIs to be converted to URLs, a !URLStreamHandlerFactory that supports the URI's scheme is required. When connecting, the !URLStreamHandler can convert the URL to a URI and then to a Path.

URLClassLoader Support

Classes may be loaded from an archive by converting the Path of its root directory to a URL and using a URLClassLoader:

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TBD

URLClassLoader Support

TBD

ToDos

• a way to read the zip’s central directory
• a way to seek into a deflated zip entry without inflating the entire thing
• is a ClassLoader from a list of Path helpful?
• how to deal with the locking model on Windows platform
• how to work with Paths that are directories - do we get this for free?
• how to use the WatchService to detect changes e.g. web.xml or *.jsp touched?

Performance Measurements

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Limitations in standard JDK APIs

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The JDK API dealing with Zip archives have not been updated to work with the NIO File APIs:

• ZipFile's constructor only accepts a java.io.File or a String relating to a file on the default filesystem
• A zip entry may only be accessed as a sequential InputStream rather than a SeekableByteChannel
• A ZipInputStream may only be constructed over an InputStream rather than a SeekableByteChannel

The JDK implementation of Zip support uses the native zlib library and maps the archive into memory for direct access and performance. This has implications:

• The archive content must be accessible from native code
• Memory mapping a file on some operating systems (e.g. Microsoft Windows) asserts a mandatory file lock which interferes with the "overwrite to re-deploy" mechanism often used in development environments

URL Support

The jar scheme syntax is now formally defined as:

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