'\" t .\" Copyright (c) 1994, 2013, Oracle and/or its affiliates. All rights reserved. .\" Arch: generic .\" Software: JDK 8 .\" Date: 21 November 2013 .\" SectDesc: Basic Tools .\" Title: javah.1 .\" .if n .pl 99999 .TH javah 1 "21 November 2013" "JDK 8" "Basic Tools" .\" ----------------------------------------------------------------- .\" * Define some portability stuff .\" ----------------------------------------------------------------- .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .\" http://bugs.debian.org/507673 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" ----------------------------------------------------------------- .\" * set default formatting .\" ----------------------------------------------------------------- .\" disable hyphenation .nh .\" disable justification (adjust text to left margin only) .ad l .\" ----------------------------------------------------------------- .\" * MAIN CONTENT STARTS HERE * .\" ----------------------------------------------------------------- .SH NAME javah \- Generates C header and source files from a Java class\&. .SH SYNOPSIS .sp .nf \fBjavah\fR [ \fIoptions\fR ] f\fIully\-qualified\-class\-name \&.\&.\&.\fR .fi .sp .TP \fIoptions\fR The command-line options\&. See Options\&. .TP \fIfully-qualified-class-name\fR The fully qualified location of the classes to be converted to C header and source files\&. .SH DESCRIPTION The \f3javah\fR 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 an object\&'s instance variables from native source code\&. The \f3\&.h\fR file contains a \f3struct\fR definition with a layout that parallels the layout of the corresponding class\&. The fields in the \f3struct\fR correspond to instance variables in the class\&. .PP The name of the header file and the structure declared within it are derived from the name of the class\&. When the class passed to the \f3javah\fR command is inside a package, the package name is added to the beginning of both the header file name and the structure name\&. Underscores (_) are used as name delimiters\&. .PP By default the \f3javah\fR command creates a header file for each class listed on the command line and puts the files in the current directory\&. Use the \f3-stubs\fR option to create source files\&. Use the \f3-o\fR option to concatenate the results for all listed classes into a single file\&. .PP The Java Native Interface (JNI) does not require header information or stub files\&. The \f3javah\fR command can still be used to generate native method function prototypes needed for JNI-style native methods\&. The \f3javah\fR command produces JNI-style output by default and places the result in the \f3\&.h\fR file\&. .SH OPTIONS .TP -o \fIoutputfile\fR .br Concatenates the resulting header or source files for all the classes listed on the command line into an output file\&. Only one of \f3-o\fR or \f3-d\fR can be used\&. .TP -d \fIdirectory\fR .br Sets the directory where the \f3javah\fR command saves the header files or the stub files\&. Only one of \f3-d\fR or \f3-o\fR can be used\&. .TP -stubs .br Causes the \f3javah\fR command to generate C declarations from the Java object file\&. .TP -verbose .br Indicates verbose output and causes the \f3javah\fR command to print a message to \f3stdout\fR about the status of the generated files\&. .TP -help .br Prints a help message for \f3javah\fR usage\&. .TP -version .br Prints \f3javah\fR command release information\&. .TP -jni .br Causes the \f3javah\fR command to create an output file containing JNI-style native method function prototypes\&. This is the default output; use of \f3-jni\fR is optional\&. .TP -classpath \fIpath\fR .br Specifies the path the \f3javah\fR command uses to look up classes\&. Overrides the default or the \f3CLASSPATH\fR environment variable when it is set\&. Directories are separated by colons on Oracle Solaris and semicolons on Windows\&. The general format for path is: \fIOracle Solaris\fR: \&.:\fIyour-path\fR Example: \f3\&.:/home/avh/classes:/usr/local/java/classes\fR \fIWindows\fR: \&.;\fIyour-path\fR Example: \f3\&.;C:\eusers\edac\eclasses;C:\etools\ejava\eclasses\fR As a special convenience, a class path element that contains a base name of * is considered equivalent to specifying a list of all the files in the directory with the extension \f3\&.jar\fR or \f3\&.JAR\fR\&. For example, if directory \f3mydir\fR contains \f3a\&.jar\fR and \f3b\&.JAR\fR, then the class path element \f3mydir/*\fR is expanded to a \f3A\fR\f3\&.jar:b\&.JAR\fR, except that the order of jar files is unspecified\&. All JAR files in the specified directory, including hidden ones, are included in the list\&. A class path entry that consists of * expands to a list of all the JAR files in the current directory\&. The \f3CLASSPATH\fR environment variable, where defined, is similarly expanded\&. Any class path wild card expansion occurs before the Java Virtual Machine (JVM) is started\&. A Java program will never see unexpanded wild cards except by querying the environment\&. For example, by calling \f3System\&.getenv("CLASSPATH")\fR\&. .TP -bootclasspath \fIpath\fR .br Specifies the path from which to load bootstrap classes\&. By default, the bootstrap classes are the classes that implement the core Java platform located in \f3jre\elib\ert\&.jar\fR and several other JAR files\&. .TP -old .br Specifies that old JDK 1\&.0-style header files should be generated\&. .TP -force .br Specifies that output files should always be written\&. .TP -J\fIoption\fR .br Passes \f3option\fR to the Java Virtual Machine, where \f3option\fR is one of the options described on the reference page for the Java application launcher\&. For example, \f3-J-Xms48m\fR sets the startup memory to 48 MB\&. See java(1)\&. .SH SEE\ ALSO .TP 0.2i \(bu javah(1) .TP 0.2i \(bu java(1) .TP 0.2i \(bu jdb(1) .TP 0.2i \(bu javap(1) .TP 0.2i \(bu javadoc(1) .RE .br 'pl 8.5i 'bp