diff --git a/interop/src/cpp/vmloader.cc b/interop/src/cpp/vmloader.cc
index 207f5c6d919b12e660b8b85c9b23e2d915e3dc7b..195f0f205a1940d8694eb549d3eefc3607a88717 100644
--- a/interop/src/cpp/vmloader.cc
+++ b/interop/src/cpp/vmloader.cc
@@ -251,7 +251,7 @@ const AppInfo javaAppInfo = {
     "createApplication",
     "()Lorg/koalaui/arkoala/Application;",
     "start",
-    "()J"
+    "()J",
     "enter",
     "(II)Z",
 };
@@ -288,11 +288,29 @@ extern "C" DLL_EXPORT KNativePointer StartApplication() {
     if (g_vmEntry.vmKind == JAVA_VM_KIND) {
         JNIEnv* jEnv = (JNIEnv*)(g_vmEntry.env);
         jclass appClass = jEnv->FindClass(appInfo->className);
-        jmethodID start = jEnv->GetStaticMethodID(appClass, appInfo->startMethodName, appInfo->startMethodSig);
-        jobject app = jEnv->NewGlobalRef(jEnv->CallStaticObjectMethod(appClass, start));
+        if (!appClass) {
+            fprintf(stderr, "Cannot load main class %s\n", appInfo->className);
+            return nullptr;
+        }
+        jmethodID create = jEnv->GetStaticMethodID(appClass, appInfo->createMethodName, appInfo->createMethodSig);
+        if (!create) {
+            fprintf(stderr, "Cannot find create method %s\n", appInfo->createMethodName);
+            return nullptr;
+        }
+        jobject app = jEnv->NewGlobalRef(jEnv->CallStaticObjectMethod(appClass, create));
         g_vmEntry.app = (void*)app;
+        g_vmEntry.start = (void*)(jEnv->GetMethodID(appClass, appInfo->startMethodName, appInfo->startMethodSig));
+        if (!g_vmEntry.start) {
+            fprintf(stderr, "Cannot find start method %s %s\n", appInfo->startMethodName,appInfo->startMethodSig);
+            return nullptr;
+        }
         g_vmEntry.enter = (void*)(jEnv->GetMethodID(appClass, appInfo->enterMethodName, appInfo->enterMethodSig));
-        return 0;
+        if (!g_vmEntry.enter) {
+            fprintf(stderr, "Cannot find enter method %s %s\n", appInfo->enterMethodName,appInfo->enterMethodSig);
+            return nullptr;
+        }
+        auto result = reinterpret_cast<KNativePointer>(jEnv->CallLongMethod((jobject)(g_vmEntry.app), (jmethodID)(g_vmEntry.start)));
+        return result;
     }
     #endif
     #ifdef KOALA_ETS_NAPI
@@ -313,8 +331,15 @@ extern "C" DLL_EXPORT KNativePointer StartApplication() {
         g_vmEntry.app = (void*)app;
 
         g_vmEntry.start = (void*)(etsEnv->Getp_method(appClass, appInfo->startMethodName, appInfo->startMethodSig));
-        etsEnv->CallStaticObjectMethod(appClass, create);
+        if (!g_vmEntry.start) {
+            fprintf(stderr, "Cannot find create method %s\n", appInfo->startMethodName);
+            return nullptr;
+        }
         g_vmEntry.enter = (void*)(etsEnv->Getp_method(appClass, appInfo->enterMethodName, appInfo->enterMethodSig));
+        if (!g_vmEntry.enter) {
+            fprintf(stderr, "Cannot find enter method %s\n", appInfo->enterMethodName);
+            return nullptr;
+        }
         auto result = reinterpret_cast<KNativePointer>(etsEnv->CallLongMethod((ets_object)(app), (ets_method)(g_vmEntry.start)));
         return result;
     }