Get/ReleaseStringUTFChars

Question

From a Java method "Connection_Open" I am trying to call a C function "Open" which has two strings as input parameters, and returns a connection number as an output parameter:
JNIEXPORT jint JNICALL
Java_Connection_Open(JNIEnv *env, jobject obj, jstring jhostname, jstring jfilename, jint interval)
const char chostname = (env)->GetStringUTFChars(env, jhostname, 0);
const char cfilename = (env)->GetStringUTFChars(env, jfilename, 0);
int connection = -1;
Open(chostname, cfilename, &connection, interval);
(*env)->ReleaseStringUTFChars(env, jhostname, chostname);
(*env)->ReleaseStringUTFChars(env, jfilename, cfilename);
return connection;
When I run my code in UNIX I get the following errors:
ld.so.1: java: fatal: /usr/local/lib/libJavaC.so: required mapping 0x10000 size 0x14000, is already in use by file java (/usr/local/lib/libJavaC.so)
java.lang.UnsatisfiedLinkError: no JavaC in shared library path
I am guessing that the UnsatisfiedLinkError occurs because of the mapping problem with libJavaC.so, but I don't know why the mapping problem occurs.
Am I doing something wrong with creating and disposing of the UTFString(s)?

Answer 1

Your COULD have a problem with the ReleaseStringUTF calls. If you look at the docs on GetStringUTF, they say that the last parameter should be a pointer to a boolean which says whether or not a copy of the data was made. If it was NOT, then you shouldn't call the relase function.
What you have done is not supply a boolean pointer, and not checked; you could be releasing non-existant copies.
on the other hand, maybe this is not the problem.