javah produces C header files and C source files from
a Java class. These files provide the connective glue that allow
your Java and C code to interact.
javah generates C header and source files that are needed to
implement native methods. The generated header and source files
are used by C programs to reference an object's instance variables from
native source code. The .h file contains a struct definition whose
layout parallels the layout of the corresponding class. The fields
in the struct correspond to instance variables in the class.
The name of the header file and the structure declared within it are
derived from the name of the class. If the class passed to javah is
inside a package, the package name is prepended to both the header file name
and the structure name. Underscores (_) are used as name delimiters.
By default javah creates a header file for each class listed
on the command line and puts the files in the current directory.
Use the -stubs option to create source files.
Use the -o option to concatenate the results for all listed classes
into a single file.
The new native method interface, Java Native Interface (JNI), does not require header information
or stub files. javah can still be used
to generate native method function proptotypes needed for JNI-style native
methods. javah produces JNI-style output by default, and places the result in the .h file.
javah_g is a non-optimized version of javah suitable for use with
debuggers like jdb.
Concatenates the resulting header or source files for all the
classes listed on the command line into outputfile. Only
one of -o or -d may be used.
-d directory
Sets the directory where javah saves the header files
or the stub files. Only one of -d or -o may be used.
-stubs
Causes javah to generate C declarations from the Java
object file.
-verbose
Indicates verbose output and causes javah to print a message to stdout concerning the status of
the generated files.
-help
Print help message for javah usage.
-version
Print out javah version information.
-jni
Causes javah to create an output file containing JNI-style native
method function prototypes. This is the default output, so use of
-jni is optional.
-classpath path
Specifies the path javah uses to look up classes. Overrides the default
or the CLASSPATH environment variable if it is set. Directories are separated by
semi-colons. Thus the general format for path is:
.;<your_path>
For example:
.;C:\users\dac\classes;C:\tools\java\classes
-bootclasspath path
Specifies path from which to load bootstrap classes. By default,
the bootstrap classes are the classes implementing the core Java
platform located in jre\lib\rt.jar and jre\lib\i18n.jar.
-old
Specifies that old JDK1.0-style header files should be generated.
-force
Specifies that output files should always be written.
-Joption
Pass option to the Java virtual machine, where
option is one of the options described on the
reference page for the java application
launcher. For example, -J-Xms48m sets the startup
memory to 48 megabytes.
ENVIRONMENT VARIABLES
CLASSPATH
Used to provide the system a path to user-defined classes. Directories are
separated by semi-colons, for example,