Serializing and deserializing a blank URI returns null

[pgieser]

Here is a failing test:

    public void test() throws Exception {
        URI blankUri = URI.create("");
        assertNotNull(blankUri);

        ObjectMapper objectMapper = new ObjectMapper();

        assertNotNull("serialized and deserialized blank URI should not be null",
                objectMapper.readValue(objectMapper.writeValueAsString(blankUri), URI.class));
    }

[cowtowncoder]

Hmmh. Is empty String really valid for URI creation? Interesting...

[pgieser]

It's an admitted edge case. The URI javadoc specifies a few exceptions to RFC 2396 that perhaps allow an empty string to be parsed without generating an exception.

[pgieser]

Actually, I think the issue is that URI can represent not just absolute URI's, but also URI references.

From Wikipedia:

A URI reference may take the form of a full URI, or just the scheme-specific portion of one, or even some trailing component thereof – even the empty string.

[cowtowncoder]

Ok. Given this definition there is a meaningful definition for empty String, aside from missing (null) value. Should be easy enough to fix; I am guessing deserializer just has specific check to consider it null.

[pgieser]

Looks like FromStringDeserializer short-circuits to return null on an empty string instead of delegating immediately to URIDeserializer.