code: public String sandboxPolicy(String workerId, Map<String, String> replaceMap) throws IOException {
          if (!isEnable) {
              return "";
          }
  
          replaceMap.putAll(replaceBaseMap);
          String tmpPolicy = generatePolicyFile(replaceMap);
  
          File file = new File(tmpPolicy);
          String policyPath = StormConfig.worker_root(conf, workerId) + File.separator + SANBOX_TEMPLATE_NAME;
          File dest = new File(policyPath);
          file.renameTo(dest);
  
          StringBuilder sb = new StringBuilder();
          sb.append(" -Djava.security.manager -Djava.security.policy=");
          sb.append(policyPath);
  
          return sb.toString();
      }
docs: Generate command string