To suppress serializing properties with null values using Jackson >2.0, you can configure the ObjectMapper directly, or make use of the @JsonInclude annotation:
mapper.setSerializationInclusion(Include.NON_NULL);
or:
@JsonInclude(Include.NON_NULL)
class Foo
{
String bar;
}
Alternatively, you could use @JsonInclude in a getter so that the attribute would be shown if the value is not null.
A more complete example is available in my answer to How to prevent null values inside a Map and null fields inside a bean from getting serialized through Jackson.