OSGi bundle JNI load/unload problem

Question

Hi everybody!!
One more thread about the topic. I still didn't find a solution. Can anybody help me?
I have an OSGi bundle that access native methods from a JNI library (for a medical device). I could make my bundle work once, but the second time I tried to access the methods, the dll was still in use I couldn't get data from the methods.
This is the class I used (I even tried with a custom libloader):
public class Omron637ITjni {
     /*Native functions from the JNI dll*/
     public native int OmronInit();
     public native int OmronClose();
     public native int OmronFinish();
     public native int OmronOpen(int disp);
     public native int OmronRead(MeasurementData MData, int pos);
     public native void OmronNumRead(DataCount DCount);
     static{
          //Using LibLoader
          /*try {
          LibLoader.loadCommLib("omron637IT");
          catch ( Exception x ) {
          // do what is necessary
               System.out.println(x);
          //Using System Commander
          try{
               System.out.println("Charging Library Omron");
               System.loadLibrary("omron637IT");
          }catch(UnsatisfiedLinkError unsatisfiedlinkerror)
System.out.println("Error loading library: " + unsatisfiedlinkerror);
As it seems not to work, I'm trying with Singleton pattern. This is my new class:
public class Omron637ITjni_Singleton {
          * Native functions from the JNI dll
          public native int OmronInit();
          public native int OmronClose();
          public native int OmronFinish();
          public native int OmronOpen(int disp);
          public native int OmronRead(MeasurementData MData, int pos);
          public native void OmronNumRead(DataCount DCount);
          private static Omron637ITjni_Singleton singleton;
          * Instance accessor following singleton.
          public static Omron637ITjni_Singleton getInstance() {
               if (singleton == null){
                    System.out.println("Create Object");
                    singleton = new Omron637ITjni_Singleton();
               else{
                    System.out.println("Object already created; use instance");
               return singleton;
          * Private constructor to ensure that a <tt>ResourceManager</tt>
          * cannot be constructed from outside this class.
          private Omron637ITjni_Singleton() {     
          static{
               //Using LibLoader
               /*try {
               LibLoader.loadCommLib("omron637IT");
               catch ( Exception x ) {
               // do what is necessary
                    System.out.println(x);
               try {
                    System.out.println("Charging Omron library from Singleton");
                    System.loadLibrary("omron637IT");
                    System.out.println("Library charged");
               } catch (UnsatisfiedLinkError ule) {
                    System.out.println("Error loading library: " + ule);
At this very moment, when executing
Omron637ITjni_Singleton jni = Omron637ITjni_Singleton.getInstance();
from the Activator, I get from the Knopflerfish console:
[stdout] omron637ITBPM starting...
[stdout] Service registered: Omron 637IT Blood Pressure Monitor
[stdout] Charging Library Omron desde Singleton
[stdout] Library chatged
[stdout] Create object
Then, I call a services provided by the bundle:
framework call omron637IT.Omron637ITInterface getData
which calls the following function:
public void getData() {
          // TODO Auto-generated method stub
          //Omron637ITjni jni = new Omron637ITjni();
          //Singleton
          Omron637ITjni_Singleton jni = Omron637ITjni_Singleton.getInstance();
          try {
               int res = jni.OmronInit();
               int ok_open = jni.OmronOpen(res);
               System.out.println("The attempt of connecting the Omron637IT device ended with code: " + ok_open + " [(0) normal (1) still in process (2) error]");
               if (ok_open == 0){ //OK
                    DataCount NumData = new DataCount();
                    jni.OmronNumRead(NumData);
                    System.out.println("DATA");
                    System.out.println("----");
                    for (int pos = 0;pos<NumData.nData1;pos++){
                         MeasurementData Data = new MeasurementData();
                         int ok_read = jni.OmronRead(Data,pos);
                         int annyo = Data.cYear + 2000;
                         int i = pos + 1;
                         if (ok_read == 0)
                              System.out.println("Num: " + i + "; Date-> " + Data.cDay + "/" + Data.cMonth + "/" + annyo + "; Time-> " + Data.cTime + ":" + Data.cMinute + ":" + Data.cSecond + "; Sys-> " + Data.nSys + "; Dia-> " + Data.cDia + "; Pls-> " + Data.cPls);
                    int stop = jni.OmronClose();
                    System.out.println("Close with code " + stop + " Right?");
                    int finish = jni.OmronFinish();
                    System.out.println("Finish with code " + finish + " Right?");
                    System.gc();
                    System.gc();
               else
                    System.out.println("The process of opening the device ended with error");
          }catch (UnsatisfiedLinkError ule) {
               System.out.println("BRUTAL ERROR: " + ule);
[stdout] The objeto already exists
[stdout] BRUTAL ERROR: java.lang.UnsatisfiedLinkError: OmronInit
Result: null
which indicates that this time I'm using the same instance of the singleton class created in the activation process, but that I cannot access the method. ANY HINT??
I also provide you the JNI dll code (because I add the exporting of the JNI_OnLoad & OnUnload methods:
.h
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class omron637IT_Omron637ITjni */
#ifndef Includedomron637IT_Omron637ITjni
#define Includedomron637IT_Omron637ITjni
#ifdef __cplusplus
extern "C" {
#endif
* OnLoad & UnLoad
JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM vm, void reserved);
JNIEXPORT void JNICALL JNI_OnUnload(JavaVM vm, void reserved);      
* Class: omron637IT_Omron637ITjni
* Method: OmronInit
* Signature: ()I
JNIEXPORT jint JNICALL Java_omron637IT_Omron637ITjni_OmronInit
(JNIEnv *, jobject);
* Class: omron637IT_Omron637ITjni
* Method: OmronOpen
* Signature: (I)I
JNIEXPORT jint JNICALL Java_omron637IT_Omron637ITjni_OmronOpen
(JNIEnv *, jobject, jint);
* Class: omron637IT_Omron637ITjni
* Method: OmronRead
* Signature: (Lomron637IT/MeasurementData;I)I
JNIEXPORT jint JNICALL Java_omron637IT_Omron637ITjni_OmronRead
(JNIEnv *, jobject, jobject, jint);
* Class: omron637IT_Omron637ITjni
* Method: OmronNumRead
* Signature: (Lomron637IT/DataCount;)V
JNIEXPORT void JNICALL Java_omron637IT_Omron637ITjni_OmronNumRead
(JNIEnv *, jobject, jobject);
* Class: omron637IT_Omron637ITjni
* Method: OmronClose
* Signature: ()I
JNIEXPORT jint JNICALL Java_omron637IT_Omron637ITjni_OmronClose
(JNIEnv *, jobject);
* Class: omron637IT_Omron637ITjni
* Method: OmronFinish
* Signature: ()I
JNIEXPORT jint JNICALL Java_omron637IT_Omron637ITjni_OmronFinish
(JNIEnv *, jobject);
#ifdef __cplusplus
#endif
#endif
and part of the code (.cpp):
JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM vm, void reserved)
     return JNI_VERSION_1_4;
JNIEXPORT void JNICALL JNI_OnUnload(JavaVM vm, void reserved)
JNIEXPORT jint JNICALL Java_omron637IT_Omron637ITjni_OmronInit
(JNIEnv *env, jobject obj)
     iNumberOflist = DEVLISTMAX;
     iSpeed = USF_SPEED4800;
     iStopBit = USF_STOP2;
     iProduct = USF_BPM;
     ret = USF_Search(hDlg, iSpeed, iStopBit, iProduct, DevList, &iNumberOflist);
     return iNumberOflist;
Can anybody tell me what I'm doing wrong???. This really drives me crazy
BR & very thanks in advance for any input.

Answer 1

This is a known bug. Check out http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4712793