Problem related to generation of header file

Question

hi guys,
I am getting Exception during the generation of the header file,
using "javah -jni HelloWorld"
I am refering jni.pdf (java.sun.com/docs/books/jni/download/jni.pdf )
I have given that error below
Exception in thread "main" java.io.IOException: can't find class file HelloWorld.class in java.net.URLClassLoader
{urls=[file:/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre/lib/rt.jar],
parent=gnu.gcj.runtime.SystemClassLoader{urls=[file:./],
parent=gnu.gcj.runtime.ExtensionClassLoader{urls=[], parent=null}}}
at gnu.classpath.tools.javah.Main.getClass(libgcj-tools.so.8rh)
at gnu.classpath.tools.javah.Main.run(libgcj-tools.so.8rh)
at gnu.classpath.tools.javah.Main.main(libgcj-tools.so.8rh)

Answer 1

ejp wrote:
GCJ is what you get in Linux (definitely Ubuntu anyway) as the default Java implementation.GCJ isn't a Java implementation at all, as you will discover when you read its documentation attentively. This is because it doesn't pass the Java certification tests. Ergo whatever it may be it isn't Java.
This is because of the license for Java not being compatible with the Ubuntu distro license.That may be so, or have been so, but it still isn't Java.I guess if you want to label it, it is the GNU Compiler for Java and associated runtimes. As an open source project for when Java licensing was not very compatible with Linux it served a purpose (even if it served it badly).
The following is from the GCJ web site. I guess they don't really claim to be 100% Java compliant.
GCJ is a portable, optimizing, ahead-of-time compiler for the Java Programming Language. It can compile Java source code to Java bytecode (class files) or directly to native machine code, and Java bytecode to native machine code.
Compiled applications are linked with the GCJ runtime, libgcj, which provides the core class libraries, a garbage collector, and a bytecode interpreter. libgcj can dynamically load and interpret class files, resulting in mixed compiled/interpreted applications. It has been merged with GNU Classpath and supports most of the 1.4 libraries plus some 1.5 additions.The first step for me with Linux was always to install the Sun JDK so never really found out how bad it really was :)
Cheers,
Shane