code: public String getLicenseKey() {
          SecurityManager sm = System.getSecurityManager();
          if (sm != null) {
              sm.checkPermission(new HazelcastRuntimePermission("com.hazelcast.config.Config.getLicenseKey"));
          }
          return licenseKey;
      }
docs: Returns the license key for this hazelcast instance. The license key
  is used to enable enterprise features.
  
  @return the license key
  @throws SecurityException If a security manager exists and the calling method doesn't have corresponding
  {@link HazelcastRuntimePermission}