javah

[Jonathan Gibbons]

On 03/12/2012 12:30 PM, Greg Brown wrote:
>>> Has the behavior of javah changed in Java 7? I'm using the<javah>   task in Ant to generate some JNI headers. When I run my Ant script under Java 6, I only get headers for classes I explicitly specify. Under Java 7, I get headers for all of my specified classes as well as any nested classes defined by those classes, even though the nested classes themselves don't specify any native methods.
>>>
>>> I'm not sure if Ant or javah is responsible for the change, but if it is javah - is this intentional, or is it a bug?
>>>
>>> Thanks,
>>> Greg
>>>
>> javah was rewritten in JDK 7, but the intent was the headers generated should be the same as for earlier versions of javah.
> So, to confirm - the fact that these headers were are generated in Java 6 but are generated in Java 7 is likely a bug?
>
>
>

Greg,

I see the same behavior on JDK 5, 6, 7, 8.

Here's my test program:
> package p;
>
> class C {
>     native void m();
>
>     class Inner {
>         void m2() { }
>     }
> }

Here's my test script:
> #!/bin/sh
>
> rm -rf play/classes play/jdk*
>
> mkdir play/classes
> /opt/jdk/1.5.0/bin/javac -d play/classes $(find play/src -name \*.java)
>
> for i in 5 6 7 8 ; do
>     mkdir play/jdk$i
>     /opt/jdk/1.$i.0/bin/javah -classpath play/classes -d play/jdk$i p.C
> done
>
> find play/jdk*

And here's the output:
> $ sh -x play/test.sh
> + rm -rf play/classes play/jdk5 play/jdk6 play/jdk7 play/jdk8
> + mkdir play/classes
> + find play/src -name *.java
> + /opt/jdk/1.5.0/bin/javac -d play/classes play/src/p/C.java
> + mkdir play/jdk5
> + /opt/jdk/1.5.0/bin/javah -classpath play/classes -d play/jdk5 p.C
> + mkdir play/jdk6
> + /opt/jdk/1.6.0/bin/javah -classpath play/classes -d play/jdk6 p.C
> + mkdir play/jdk7
> + /opt/jdk/1.7.0/bin/javah -classpath play/classes -d play/jdk7 p.C
> + mkdir play/jdk8
> + /opt/jdk/1.8.0/bin/javah -classpath play/classes -d play/jdk8 p.C
> + find play/jdk5 play/jdk6 play/jdk7 play/jdk8
> play/jdk5
> play/jdk5/p_C_Inner.h
> play/jdk5/p_C.h
> play/jdk6
> play/jdk6/p_C_Inner.h
> play/jdk6/p_C.h
> play/jdk7
> play/jdk7/p_C_Inner.h
> play/jdk7/p_C.h
> play/jdk8
> play/jdk8/p_C_Inner.h
> play/jdk8/p_C.h

-- Jon