/usr/lib/jvm/java-1.9-openjdk/bin/javah

Warning: The javah tool is planned to be removed in the next major
JDK release. The tool has been superseded by the '-h' option added
to javac in JDK 8. Users are recommended to migrate to using the
javac '-h' option; see the javac man page for more information.

Usage:
  javah [options] <classes>
where [options] include:
  -o <file>                    Output file (only one of -d or -o may be used)
  -d <dir>                     Output directory
  -v  -verbose                 Enable verbose output
  -h  --help  -?               Print this message
  -version                     Print version information
  -jni                         Generate JNI-style header file (default)
  -force                       Always write output files
  --module-path <path>         Path from which to load application modules
  --system <jdk>               Specify where to find system modules
  --class-path <path>          Path from which to load classes
  -classpath <path>            Path from which to load classes
  -cp <path>                   Path from which to load classes
  -bootclasspath <path>        Path from which to load bootstrap classes

GNU-style options may use = instead whitespace to separate the name of an option
from its value.

Each class must be specified by its fully qualified names, optionally
prefixed by a module name followed by /. Examples:
    java.lang.Object
    java.base/java.io.File