OP-421 Groovy to Java
Converted the MarketplaceServiceImpl
* this service made heavy use of Groovy JsonSlurper. I had to serialize to a Map with Jackson and then do a lot of nasty type casting
* this service used the Apache HTTPClient but only for a simple GET request. I replaced it with java.net to cut off that dependency
* This service only has one public method but it needs to do a lot of stuff so I tried to consolidate things into private classes
* This serivce uses the OwfConfigService which returns Map<Object,Object> so again the casting was awkward in Java