使用collect方法将JavaRDD<DependencyLink>转成List<DependencyLink>时出错

DependencyLink是一个类，字段包括parent、child、callCount、errorCount、appName 和dev 。其中，前四个字段是zipkin-dependencies源码自带的，后面两个字段是我新增的。我获取到了JavaRDD数据后，将里面的字段全部打印输出，每个字段都有数据，但在JavaRDD的基础上再使用collect()方法后，自己添加的字段值就没有了

JavaPairRDD<Tuple2<String,String>, DependencyLink> objects3 = new SQLContext(sc).read()
            .format("org.apache.spark.sql.execution.datasources.jdbc.JdbcRelationProvider")
            .options(options)
            .load()
            .toJavaRDD()
            .groupBy(rowTraceId)
            .flatMapValues(new RowsToDependencyLinks(logInitializer, hasTraceIdHigh))
            .values()
            .mapToPair(l -> Tuple2.apply(Tuple2.apply(l.parent(), l.child()), l));
    JavaRDD<DependencyLink> objects5 = objects3.values();
    class ForeachFunTest5 implements VoidFunction<DependencyLink>, Serializable {       
        private static final long serialVersionUID = -4892194648703458594L;
        @Override
        public void call(DependencyLink t) throws Exception {
            System.out.println("MySQLDependenciesJob------ values after reduceByKey parent = " + t.parent());
            System.out.println("MySQLDependenciesJob------ values after reduceByKey child = " + t.child());
            System.out.println("MySQLDependenciesJob------ values after reduceByKey appName = " + t.appName());
            System.out.println("MySQLDependenciesJob------ values after reduceByKey dev = " + t.dev()); 
            System.out.println("MySQLDependenciesJob------ values after reduceByKey callCount = " + t.callCount());
            System.out.println("MySQLDependenciesJob------ values after reduceByKey errorCount = " + t.errorCount());
        }
    }
    objects5.foreach(new ForeachFunTest5());
    List<DependencyLink> objects6 = objects5.collect();
    for(DependencyLink dependencyLink: objects6)  {
        System.out.println("MySQLDependenciesJob------ objects6 parent = " + dependencyLink.parent());
        System.out.println("MySQLDependenciesJob------ objects6 child = " + dependencyLink.child());
        System.out.println("MySQLDependenciesJob------ objects6 appName = " + dependencyLink.appName());
        System.out.println("MySQLDependenciesJob------ objects6 dev = " + dependencyLink.dev());
        System.out.println("MySQLDependenciesJob------ objects6 callCount = " + dependencyLink.callCount());
        System.out.println("MySQLDependenciesJob------ objects6 errorCount = " + dependencyLink.errorCount());
    }