codahale/jerkson — Issue #44: Parsing fails for Maps that contain unmarshalled keys
Author: refried
Created: 2012-02-04 21:35:42+00:00
State: open

The following code snippets works just fine:
```scala
import java.net.URL
parse[Map[String,URL]](generate(Map(new URL("http://foo.com") -> new URL("http://foo.com"))))
//res: Map[String,java.net.URL] = Map(http://foo.com -> http://foo.com)
```

But the following:
```scala
import java.net.URL
parse[Map[URL,URL]](generate(Map(new URL("http://foo.com") -> new URL("http://foo.com"))))
```
throws
```
org.codehaus.jackson.map.JsonMappingException: Can not construct instance of scala.collection.immutable.Map, problem: abstract types can only be instantiated with additional type information
at [Source: java.io.StringReader@1a47da2e; line: 1, column: 1]
at org.codehaus.jackson.map.JsonMappingException.from(JsonMappingException.java:163)
at org.codehaus.jackson.map.deser.StdDeserializationContext.instantiationException(StdDeserializationContext.java:233)
at org.codehaus.jackson.map.deser.AbstractDeserializer.deserialize(AbstractDeserializer.java:60)
at org.codehaus.jackson.map.ObjectMapper._readValue(ObjectMapper.java:2704)
at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1315)
at com.codahale.jerkson.Parser$class.parse(Parser.scala:83)
... 35 more
```

P.S. Thanks for a great library!