additional changes re setting mainlog and techlog in native calls

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@2577 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/hybrid/PrismHybrid.cc

@@ -318,9 +318,13 @@ JNIEXPORT void JNICALL Java_hybrid_PrismHybrid_PH_1FreeGlobalRefs(JNIEnv *env, j
 {
 	// delete all global references
 	env->DeleteGlobalRef(main_log_cls);
+	main_log_cls = NULL;
 	env->DeleteGlobalRef(tech_log_cls);
+	tech_log_cls = NULL;
 	env->DeleteGlobalRef(main_log_obj);
+	main_log_obj = NULL;
 	env->DeleteGlobalRef(tech_log_obj);
+	tech_log_obj = NULL;
 }
 
 //------------------------------------------------------------------------------

prism/src/mtbdd/PrismMTBDD.cc

@@ -281,9 +281,13 @@ JNIEXPORT void JNICALL Java_mtbdd_PrismMTBDD_PM_1FreeGlobalRefs(JNIEnv *env, jcl
 {
 	// delete all global references
 	env->DeleteGlobalRef(main_log_cls);
+	main_log_cls = NULL;
 	env->DeleteGlobalRef(tech_log_cls);
+	tech_log_cls = NULL;
 	env->DeleteGlobalRef(main_log_obj);
+	main_log_obj = NULL;
 	env->DeleteGlobalRef(tech_log_obj);
+	tech_log_obj = NULL;
 }
 
 //------------------------------------------------------------------------------

prism/src/sparse/PrismSparse.cc

@@ -315,9 +315,13 @@ JNIEXPORT void JNICALL Java_sparse_PrismSparse_PS_1FreeGlobalRefs(JNIEnv *env, j
 {
 	// delete all global references
 	env->DeleteGlobalRef(main_log_cls);
+	main_log_cls = NULL;
 	env->DeleteGlobalRef(tech_log_cls);
+	tech_log_cls = NULL;
 	env->DeleteGlobalRef(main_log_obj);
+	main_log_obj = NULL;
 	env->DeleteGlobalRef(tech_log_obj);
+	tech_log_obj = NULL;
 }
 
 //------------------------------------------------------------------------------