GetJavaVM: Passed JNIEnv* has no MokapotEnv* associated

Error message

GetJavaVM: Passed JNIEnv* has no MokapotEnv* associated

What it means

Error "GetJavaVM: Passed JNIEnv* has no MokapotEnv* associated" thrown in oracle/graal.

Source

Thrown at espresso/src/com.oracle.truffle.espresso.native/src/nespresso.c:468

    }
  }
  return ret;
}

jint GetJavaVM(JNIEnv *env, JavaVM **vmPtr) {
  MokapotEnv* moka_env = NULL;
  JavaVM* vm = NULL;
  if (vmPtr == NULL) {
    return JNI_ERR;
  }
  if (env == NULL) {
    fprintf(stderr, "GetJavaVM: Passed JNIEnv* is NULL" OS_NEWLINE_STR);
    return JNI_ERR;
  }

  moka_env = (MokapotEnv*) (*env)->reserved1;
  if (moka_env == NULL) {
    fprintf(stderr, "GetJavaVM: Passed JNIEnv* has no MokapotEnv* associated" OS_NEWLINE_STR);
    return JNI_ERR;
  }

  vm = (*moka_env)->vm;

  // If there's an isolate-aware JavaVM, find it.
  if ((*vm)->reserved1 == MOKA_AMERICANO) {
    vm = (JavaVM*) (*vm)->reserved2;
    // MOKA_AMERICANO JavaVM can only point to a MOKA_LATTE.
    if ((*vm)->reserved1 != MOKA_LATTE) {
      fprintf(stderr, "GetJavaVM: not a MOKA_LATTE" OS_NEWLINE_STR);
      return JNI_ERR;
    }
  } else if ((*vm)->reserved1 != MOKA_RISTRETTO) {
    fprintf(stderr, "GetJavaVM: not a MOKA_RISTRETTO" OS_NEWLINE_STR);
    return JNI_ERR;
  }

View on GitHub (pinned to a66e9ccd1d)

Solutions

Fix the condition reported by the error: GetJavaVM: Passed JNIEnv* has no MokapotEnv* associated
Check the throwing call site and ensure its documented preconditions (argument values, types, environment, or configuration) are satisfied before the call.

Example fix

Validate inputs and environment so that the failing condition does not occur: GetJavaVM: Passed JNIEnv* has no MokapotEnv* associated

When it happens

Trigger: Thrown at espresso/src/com.oracle.truffle.espresso.native/src/nespresso.c:468 when the library encounters an invalid state.

Common situations: Occurs when a caller violates the contract guarded by this check: GetJavaVM: Passed JNIEnv* has no MokapotEnv* associated

AI-assisted analysis of oracle/graal@a66e9ccd1d (2026-08-14). Data as JSON: /api/errors/222893b6cd0c419b. Report an issue: GitHub.