public void printAll(PrintWriter writer) {
    printVariable(writer, CliConstants.CONFIG_EXECUTOR, activeExecutorClassName);
    printAll(writer, shellEnvHandler);
    if (executorEnvHandler != null) {
      printAll(writer, executorEnvHandler);
    }
  }
Prints all the environment variables and their values, including both those of Shell
and of the Executor.
@param writer A writer to print to
samza-sql-shell/src/main/java/org/apache/samza/sql/client/cli/CliEnvironment.java