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gcj-dbtool - Manipulate class file mapping databases for libgcj


gcj-dbtool OPTION DBFILE [MORE] ...

gcj-dbtool [-0] [-] [-n] [-a] [-f]
[-t] [-l] [-p [LIBDIR]]
[-v] [-m] [--version] [--help]


"gcj-dbtool" is a tool for creating and manipulating class file mapping databases.
"libgcj" can use these databases to find a shared library corresponding to the bytecode
representation of a class. This functionality is useful for ahead-of-time compilation of
a program that has no knowledge of "gcj".

"gcj-dbtool" works best if all the jar files added to it are compiled using

Note that "gcj-dbtool" is currently available as "preview technology". We believe it is a
reasonable way to allow application-transparent ahead-of-time compilation, but this is an
unexplored area. We welcome your comments.


This creates a new database. Currently, databases cannot be resized; you can choose a
larger initial size if desired. The default size is 32,749.

This adds a jar file to the database. For each class file in the jar, a cryptographic
signature of the bytecode representation of the class is recorded in the database. At
runtime, a class is looked up by its signature and the compiled form of the class is
looked for in the corresponding shared library. The -a option will verify that LIB
exists before adding it to the database; -f skips this check.

Merge a number of databases. The output database overwrites any existing database.
To add databases into an existing database, include the destination in the list of

If - or -0 are used, the list of files to read is taken from standard input instead of
the command line. For -0, Input filenames are terminated by a null character instead
of by whitespace. Useful when arguments might contain white space. The GNU find
-print0 option produces input suitable for this mode.

Test a database.

List the contents of a database.

-p Print the name of the default database. If there is no default database, this prints
a blank line. If LIBDIR is specified, use it instead of the default library directory
component of the database name.

Print a help message, then exit.

-v Print version information, then exit.

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