private static @NonNls @Nullable String toStringArray(final PsiType psiType) {
    if (psiType instanceof PsiArrayType) {
      return '[' + toStringArray(((PsiArrayType)psiType).getComponentType());
    }
    else if (psiType instanceof PsiPrimitiveType) {
      return String.valueOf(ourPrimitiveTypes.get(psiType));
    }
    else if (psiType instanceof PsiClassType) {
      return "L" + psiType.getCanonicalText() + ";";
    }
    return null;
  }
private static @NonNls @Nullable String toStringArray(final PsiType psiType)