javah(1)						      General Commands Manual							  javah(1)

NAME

       javah - C header and stub file generator

SYNOPSIS

       javah [ options ] fully-qualified-classname ...
       javah_g [ options ] fully-qualified-classname ...

DESCRIPTION

       The  javah  command  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 instance variables of an object from native source code. The .h file contains  a  structure	definition
       whose layout parallels that of the corresponding class. The fields in the structure 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.   The  javah  command  can
       still  be  used	to  generate  native  method  function prototypes needed for JNI-style native methods.	javah produces JNI-style output by
       default, and places the result in the .h file.

       The javah_g version is a non-optimized version of javah suitable for use with debuggers like jdb.

OPTIONS

       The following options are supported:

       -o outputfile  Concatenates the resulting header or source files for all the classes listed on the command line into outputfile.  Only  the
		      -o or -d option may be used.

       -bootclasspath path
		      Specifies  path  from  which  to load bootstrap classes.	By default, the bootstrap classes are the classes implementing the
		      core Java 2 platform located in jre/lib/rt.jar and several other jar files.

       -classpath path
		      Specifies the path javah uses to look up classes. Overrides the default of the CLASSPATH environment variable if it is  set.
		      Directories are separated by colons. Thus the general format for path is:

			   .:<your_path>

		      For example:

			   .:/home/avh/classes:/usr/local/java/classes

       -d directory   Sets the directory where javah saves the header files or the stub files.

       -force	      Specifies that output files should always be written.

       -help	      Prints help message for javah usage.

       -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.

       -old	      Specifies the old JDK1.0-style header files should be generated.

       -stubs	      Causes javah to generate C declarations from the Java object file.

       -trace	      Tracing is no longer supported.  Instead, use the -verbose:jni option of the virtual machine.

       -verbose       Indicates verbose output and causes javah to print a message to stdout concerning the status of the generated files.

       -version       Print out javah version information.

       -Joption       Pass option to the Java virtual machine, where option is one of the options described on the man page for the java  applica-
		      tion  launcher, java(1). For example, -J-Xms48m sets the startup memory to 48 megabytes. It is a common convention for -J to
		      pass options to the underlying virtual machine.

ENVIRONMENT VARIABLES

       CLASSPATH      Used to provide the system with a path to user-defined classes.  Directories are separated by colons, for example,

		 .:/home/avh/classes:/usr/local/java/classes

SEE ALSO

       java(1), javac(1), javadoc(1), javap(1), jdb(1)

								   13 June 2000 							  javah(1)