client-api/src/main/java/com/streamsets/datacollector/client/ApiClient.java
public String selectHeaderAccept(String[] accepts) {
    if (accepts.length == 0) return null;
    if (StringUtil.containsIgnoreCase(accepts, "application/json")) return "application/json";
    return StringUtil.join(accepts, ",");
  }
public String selectHeaderAccept(String[] accepts) {
    if (accepts.length == 0) return null;
    if (StringUtil.containsIgnoreCase(accepts, "application/json")) return "application/json";
    return StringUtil.join(accepts, ",");
  }
Select the Accept header's value from the given accepts array:
if JSON exists in the given array, use it;
otherwise use all of them (joining into a string)

@param accepts The accepts array to select from
@return The Accept header to use. If the given array is empty,
null will be returned (not to set the Accept header explicitly).