code: private Runtime getRuntime(final String requestedRuntimeName) {
  
      final String runtimeName =
          StringUtils.isBlank(requestedRuntimeName) ? this.defaultRuntimeName : requestedRuntimeName;
  
      final Runtime runtime = this.runtimes.get(runtimeName);
      Validate.notNull(runtime, "Couldn't find runtime for name " + runtimeName);
  
      return runtime;
    }
docs: Retrieves requested runtime, if requested name is empty a default runtime will be used.
  @param requestedRuntimeName the requested runtime name
  @return The runtime