World: r4wp

well, what is the .class file good for anyway, even if I have JRE?

The .class file is Java's "exe".

Java 7: I think I've relied on Java 6 docs, but it should work as 
these are old APIs.

http://bolka.at/2013/red/events.class

Hmm, on second thought, Pekr, if you don't know what .class are, 
maybe don't bother with JDK then...;-)

With the JRE, you can run code in .class files.

We'll provide precompiled classes for you to test.

Hmm, the above classes don't run for me with a Java 6 JRE. So ignore 
them, if you don't have Java 7 already.

> java -version
java version "1.6.0_21"
Java(TM) SE Runtime Environment (build 1.6.0_21-b07)
Java HotSpot(TM) Client VM (build 17.0-b17, mixed mode, sharing)

Well, looking into binary .class, I expected it being some kind of 
executable or package, just pressing Enter does nothing :-) So it 
is not mapped to JRE on my machine .... I selected it manually, and 
it says:

Could not find or load main class, or something like that ...

open a command prompt, change to the directory the .class is stored 
in, and run `java JNIdemo`

error and crash "problematic frame ...."

Pekr: > java -version

1.7.0_13

Exception Access Violation (0xc0000005)

Get a "problematic frame" crash as well (Linux, 6.0_26-b03).

Doc: for Linux to work, you need to rename the .so to libJNIdemo.so, 
and start the demo with `java -Djava.library.path=. JNIdemo`.

Andreas and Pekr: are you using 64-bit OSes?

yes

That might be related...

I might try downloading 32 bit version then ...

Will try on a 64-bit too...

I tried it on a 32b OS.

Andreas, are you using OpenJDK?

Nope. Sun's JRE.

$ java -version
java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
Java HotSpot(TM) Server VM (build 20.1-b02, mixed mode)

(/JDK)

Ah, will try to upgrade mine to 0_26 at least.

Crash seems to be in libc, so it's probably the missing dllinit code 
for ELF.

Stack: [0xb69b4000,0xb6a05000],  sp=0xb6a03ea8,  free space=319k

Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, 
C=native code)
C  [libc.so.6+0x764f3]  short+0x33
V  [libjvm.so+0x3f1541]  unsigned+0xe1
C  [libJNIdemo.so+0xc9c]  long double+0xc9c
C  [libJNIdemo.so+0xd24]  long double+0xd24
C  [libJNIdemo.so+0xefd]  Java_JNIdemo_doMain+0xbd
j  JNIdemo.doMain()V+0

It's crashing for Pekr too, and he's probably on Windows.

yes, Windows8

Do you want me to send you an error log it generated in the working 
directory?

Yes please, but in private channel (or email).

Andreas: reproduced a crash on Linux 32-bit with Java 1.6.0_27.

C  [libc.so.6+0x76550]  __strerror_r+0x190
V  [libjvm.so+0x22cc29]  jni_GetMethodID+0x99
C  [libJNIdemo.so+0xc9c]  exit+0xc9c
C  [libJNIdemo.so+0xd24]  exit+0xd24
C  [libJNIdemo.so+0xefd]  Java_JNIdemo_doMain+0xbd
j  JNIdemo.doMain()V+0
j  JNIdemo.main([Ljava/lang/String;)V+0

Java: "write once, debug everywhere" ;-)

Could someone else test it on Windows XP, 7 and 8?

Dinner time, bbl.

ok, sent to your email at red lang org ....

Thanks.

You're not declaring the calling convention of the functions in the 
interface table, so that's probably the problem on Linux

I'm not sure, but the way I read the C header, the VM parameter in 
your JVM! struct functions needs another reference level

Kaj: good points. For the VM parameter, it's unused anyway.

It's crashing anyway.

Found the cause of the error, will push a fix in a few minutes.

It's now running fine on my Linux 32-bit image.

Tested ok on Mac OSX 10.6.2 (adding the -d32 option for running the 
JVM in 32-bit mode).

The window closing is generating a Java exception on OSX, I will 
improve the code to make a more JVM-friendly exit.

hmm, nice observation, this java crap is case sensitive :-)