Auto-detect multi-argument constructor with implicit names if it is the only visible creator

[cowtowncoder]

As part of continuing work to more seamlessly support addition of argument name information (by JDK8, paranamer, or other mechanism), it makes sense to allow auto-detect of creators even without @JsonCreator annotation if:

1. All parameters have name (implicit or explicit), or are marked as injectable AND
2. There are no other visible constructors AND
3. There is no default (no-arg) constructor (which otherwise would be detected regardless of visibility)

In addition, there is one practical limitation due to existing resolution rules:

• Single-argument constructor will default to "delegating" constructor, so implicit names are only used if @JsonCreator is used to indicate "property-based" constructor use, or explicit names.

Note, too, that language modules (like jackson-module-scala) may refine rules for more accurate detection of the "main" constructor; this functionality refers to vanilla handling for Java.

[shmosel]

This fails when parameters are annotated with @JsonDeserialize or @JsonProperty.

Minimal test:

static class Person {
    Person(@JsonDeserialize String name, @JsonProperty int age) {}
}

@Test
void autoDetectWithDeserialize() throws IOException {
    new ObjectMapper()
            .registerModule(new ParameterNamesModule())
            .readValue("{\"name\":\"John\",\"age\":20}", Person.class);
}

Result:

Can not construct instance of ...$Person: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?)
 at [Source: {"name":"John","age":20}; line: 1, column: 2]
com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of ...$Person: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?)
 at [Source: {"name":"John","age":20}; line: 1, column: 2]
	at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:270)
	at com.fasterxml.jackson.databind.DeserializationContext.instantiationException(DeserializationContext.java:1456)
	at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1012)
	at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1205)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:314)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:148)
	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3798)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2842)

Tested in 2.8.5.