mapreduce - Google App Engine MapReduceSpecification exception -

rewritten simplify. why compile:

mapreducespecification.of(    "something, anything",     input,    mapper, // (extends mapper<job, long, string>)    marshallers.getlongmarshaller(),    marshallers.getstringmarshaller(),    noreducer.<long, string, string>create(),    nooutput.<string, string>create((int)1l) ); 

but not. note different "mapper" extension in comments:

mapreducespecification.of(    "something, anything",     input,    mapper, // (extends mapper<job, long, jobsummary>)    marshallers.getlongmarshaller(),    marshallers.getserializationmarshaller(),    noreducer.<long, jobsummary, jobsummary>create(),    nooutput.<jobsummary, jobsummary>create((int)1l) ); 

throws compilation exception:

the method of(string, input<i>, mapper<i,k,v>, marshaller<k>, marshaller<v>, reducer<k,v,o>, output<o,r>) in type mapreducespecification not applicable arguments (string, jobinput, jobmapper, marshaller<long>, marshaller<serializable>, noreducer<long,jobsummary,jobsummary>, nooutput<jobsummary,jobsummary>)     

jobsummary simple (for purposes of example):

public class jobsummary implements serializable {    public string text; } 

any insight bit of mystery combination of i, k, v, o, r i've missed?

duplicating serializationmarshaller class-specific implementation seems have solved it. it's unsatisfying solution, works.