jwrapper - 

Generator of Nit extern classes to wrap Java APIs.


jwrapper automates wrapping Java classes so they can be accessed from Nit code. It generates Nit extern classes by analyzing Java class files.

jwrapper reuse Nit types of already wrapped Java classes by searching in the lib/java and lib/android folders in the Nit repository. It won't wrap a class that are already is those folders.


jwrapper is designed to be installed from the contrib directory of Nit repository. (http://www.nitlanguage.org)

To initiate installation process, use make in the contrib/jwrapper directory.

jwrapper relies on nitcc that will be automatically compiled from contrib/nitcc.


The jwrapper binary can be found under contrib/jwrapper/bin directory.

jwrapper uses grep to find existing libraries, make sure that the environment variable NIT_DIR is properly set to your Nit root directory.

jwrapper uses javap to extract data from .class files, the JDK7 or higher has to be installed and must be in your $PATH. (Older versions of javap do not show generic signatures)

Usage :


The options are :

-a, --with-attributes

  • It enables extern class attributes generation. For each public attribute, there'll be a Nit attribute of the corresponding type.

-c, --comment

  • When a method contains at least one unknown type, the code generator will comment the whole method and let the client manage it. Unknown types are types that doesn't have an equivalent in Nit as of yet.

-w, --wrap

  • A minimalistic extern class will be created for each unknown type (this is the default behaviour)

-h, --help

  • Print the help message

Can't use both -c and -w together, either you comment unknown types or you wrap them.