Javah error while using it in JNI

Question

Command:

javah -jni JavaHowTo

Result:

error: cannot access JavaHowTo 
class file for JavaHowTo not found

javadoc: error -          


        

Answer 1

issue on Cygwin:

javah does not work properly from Cygwin terminal:

$ cd /cygdrive/c/Workspace/prj/bin
$ ls com/example/JavaHotTo.class
com/example/JavaHotTo.class
$ javah com.example.JavaHowTo
Error: Could not find class file for 'com.example.JavaHowTo'.

But it works perfectly using the option -classpath .

$ javah -classpath . com.example.JavaHowTo
$ ls *.h
com_example_JavaHotTo.h

More tricks:

• The option -jni is by default, therefore it is not require.
• You can give relative/absolute classpath
• But javah on MS-Windows prefers path à la C:\Workspace\prj\bin
• Use cygpath -w /cygdrive/c/Workspace/prj/bin to convert into MS-Windows format
• Use option -d your/jni/headers/path to write headers in another directory

• javah creates the path your/jni/headers/path if it does not exist (see below)

  $ javah -d jni/headers -classpath . com.example.JavaHowTo
  $ ls       jni\headers
  com_example_JavaHotTo.h
  $ javah -d jni\path -classpath . com.example.JavaHowTo
  $ ls       jni\path
  com_example_JavaHotTo.h