On Apr 5, 2009, at 9:26 AM, Saptarshi Guha wrote:
Not sure if this the right place, but I can't seem to subscribe to
the rJava
mailing list. Sorry for the noise.
The correct mailing list is stats-rosuda-devel:
http://mailman.rz.uni-augsburg.de/mailman/listinfo/stats-rosuda-devel
(The rJava mailing list was a test but it turned out that everyone is
still using stats-rosuda-devel so the idea of a separate list was
abandoned).
I have a jar file in the CLASSPATH variable. On running .jinit and
checking .jclassPath, i can see the jar file containing the class.
Yet when trying to instantaite the class, i get a class not found
error.
Can you, please, send me the exact code you're using? (I.e. exactly
the value of CLASSPATH, your platform, how you started R and
initialized rJava and what you tried to do to load the class).
A side note - preferably you should not be using the CLASSPATH
environment variable, because that is very limited and doesn't work if
you have multiple packages using Java. Instead use .jinit or .jpackage
(under the hood CLASSPATH gets converted but that is for compatibility
only).
Now If if, create my own vm (see below), and then run .jinit (which
will use my vm), i can find the class in question
(org.apache.hadoop.io.longwritable)
Is there some classloader problem in rJava?
No, more likely that your code is using the wrong class loader for
loading files. The code below sets the path in the system class loader
but that is not the loader used by R code. Since R needs to modify the
class path on the fly (as packages are loaded) it uses its own class
loader. It seems as if you are bypassing that loader and thus running
into problems (without exact details we can't tell for sure).
Cheers,
Simon
==code==
void create_vm(const char *clap) {
char* classpath = (char*) calloc(18+strlen(clap)+1, sizeof(char));
sprintf(classpath,"-Djava.class.path=%s",clap);
JavaVMInitArgs args;
JavaVMOption options[2];
args.version = JNI_VERSION_1_4;
args.nOptions = 2;
options[0].optionString = classpath;
options[1].optionString = "-Xrs";
args.options = options;
args.ignoreUnrecognized = JNI_TRUE;
JavaVM *jvms[32];
jsize vms=0;
int r=0;
r=JNI_GetCreatedJavaVMs(jvms, 32, &vms);
if (r) {
error("JNI_GetCreatedJavaVMs returned %d\n", r);
} else {
if (vms>0) {
int i=0;
while (i<vms) {
if (jvms[i]) {
if (!(*jvms[i])->AttachCurrentThread(jvms[i], (void**)&jenv,
NULL)) {
jvm=jvms[i];
break;
}
}
i++;
}
if (i==vms) error("Failed to attach to any existing JVM.");
}else {
JNI_CreateJavaVM(&jvm, (void **)&jenv, &args);
}
}
}
Saptarshi Guha
[[alternative HTML version deleted]]
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
