private static @Nullable JavaSdkVersion getRequiredJdkVersion(Sdk ideaSdk) {
    if (PsiUtil.isPathToIntelliJIdeaSources(ideaSdk.getHomePath())) return JavaSdkVersion.JDK_1_8;
    Path apiJar = getPlatformApiJar(ideaSdk.getHomePath());
    return apiJar != null ? ClsParsingUtil.getJdkVersionByBytecode(getIdeaClassFileVersion(apiJar)) : null;
  }
private static @Nullable JavaSdkVersion getRequiredJdkVersion(Sdk ideaSdk)