Question

I use jersey-client to consume a REST service.
I need both the requested Entity and the Last-Modified header.

So I do the following:

ClientResponse response = webResource.get(ClientResponse.class);
Person person = response.getEntity(Person.class);

That works. I get a response and I can marshal the Entity (wich is XML) into my POJO.
When I debug and take a look into the Headers of the response, then I see that there is a Last-Modified header set.

But when I try to retrieve the date via

response.getLastModified();

I get a NPE somewhere in URLConnectionClientHandler.

Has anyone a clue what I do wrong?

edit: as requested the trace

java.lang.NullPointerException: null
at com.sun.jersey.api.client.ClientResponse.getLastModified(ClientResponse.java:647) ~[jersey-client-1.12.jar:1.12]
at a.o.u.user.dao.impl.uds.PersonenUdsClient.getPerson(PersonenUdsClient.java:103) ~[um-user-2.5.0-Beta1-SNAPSHOT.jar:na]
at a.o.u.user.dao.impl.UserDaoUdsImpl.mergeWithUdsUser(UserDaoUdsImpl.java:282) ~[um-user-2.5.0-Beta1-SNAPSHOT.jar:na]
at a.o.u.user.dao.impl.UserDaoUdsImpl.getUserWithEmail(UserDaoUdsImpl.java:124) ~[um-user-2.5.0-Beta1-SNAPSHOT.jar:na]
at ...

edit: as npe suggested I digged into the code. I think I found the problem. Beside jersey-client I also have cxf in the classpath. Both jersey and cxf provide a class called RuntimeDelegateImpl. But CXFs version does not feature a DateHeaderDelegate. I think the wrong version (CXFs) of RuntimeDelegateImpl is taken.

By now I have not found how I can explicitely set the RuntimeDelegateImpl to use.

Answer 1

To make it a wrap.

The problem is that I have both jersey-client and cxf in the classpath. Both RuntimeDelegateImpl. But CXFs version does not feature a DateHeaderDelegate. The wrong version (CXFs) of RuntimeDelegateImpl is taken.

I solved the issue by retrieving the Last-Modified Header ‘manually’:

private Date getLastModified(ClientResponse response){
    String lastModifiedString = response.getHeaders().getFirst(
            "Last-Modified");
    if (StringUtils.isEmpty(lastModifiedString)) {
        LOG.warn("Expect to get Last-Modified header when retrieving a Person by pnr "
                + "but there is none.");
        return null;
    } else {
        try {
            // format is Thu, 21 Jun 2012 08:00:42 GMT
            return new SimpleDateFormat(
                    "EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US)
                    .parse(lastModifiedString);
        } catch (ParseException e) {
            LOG.error("Could not parse Last-Modified date "
                    + e.getMessage());
            return null;
        }
    }
}

Thanx to npe for the hints.