@BeforeClass
  public static void makeEnvModifiable() throws Exception {
    envMap = new HashMap<>();
    Class<?> envClass = Class.forName("java.lang.ProcessEnvironment");
    Field theUnmodifiableEnvironmentField = envClass.getDeclaredField("theUnmodifiableEnvironment");
    removeStaticFinalAndSetValue(theUnmodifiableEnvironmentField, envMap);
  }
This is a hack to make environment variables modifiable.
Ref: https://stackoverflow.com/questions/318239/how-do-i-set-environment-variables-from-java.
itests/hive-unit/src/test/java/org/apache/hive/service/auth/jwt/TestHttpJwtAuthentication.java