-JNIEXPORT jint JNICALL Java_org_simgrid_msg_VM_isCreated(JNIEnv* env, jobject jvm);
-JNIEXPORT jint JNICALL Java_org_simgrid_msg_VM_isRunning(JNIEnv* env, jobject jvm);
-JNIEXPORT jint JNICALL Java_org_simgrid_msg_VM_isMigrating(JNIEnv* env, jobject jvm);
-JNIEXPORT jint JNICALL Java_org_simgrid_msg_VM_isSuspended(JNIEnv* env, jobject jvm);
-JNIEXPORT jint JNICALL Java_org_simgrid_msg_VM_isResuming(JNIEnv* env, jobject jvm);
+JNIEXPORT jboolean JNICALL Java_org_simgrid_msg_VM_isCreated(JNIEnv* env, jobject jvm);
+JNIEXPORT jboolean JNICALL Java_org_simgrid_msg_VM_isRunning(JNIEnv* env, jobject jvm);
+JNIEXPORT jboolean JNICALL Java_org_simgrid_msg_VM_isMigrating(JNIEnv* env, jobject jvm);
+JNIEXPORT jboolean JNICALL Java_org_simgrid_msg_VM_isSuspended(JNIEnv* env, jobject jvm);