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Posted to user@spark.apache.org by Subshiri S <su...@gmail.com> on 2015/07/30 08:00:06 UTC
Is it Spark Serialization bug ?
Hi all, I have tried to use lambda expression in spark task, and it throws
"java.lang.IllegalArgumentException: Invalid lambda deserialization"
exception. This exception is thrown when the is code like
"transform(pRDD->pRDD.map(t->t._2))" . The code snippet is below.
JavaPairDStream<String,Integer> aggregate =
pairRDD.reduceByKey((x,y)->x+y);JavaDStream<Integer> con =
aggregate.transform((Function<JavaPairRDD<String,Integer>,
JavaRDD<Integer>>)pRDD-> pRDD.map(
(Function<Tuple2<String,Integer>,Integer>)t->t._2));
JavaPairDStream<String,Integer> aggregate =
pairRDD.reduceByKey((x,y)->x+y);JavaDStream<Integer> con =
aggregate.transform((Function<JavaPairRDD<String,Integer>,
JavaRDD<Integer>> & Serializable)pRDD-> pRDD.map(
(Function<Tuple2<String,Integer>,Integer> & Serializable)t->t._2));
The above two options didn't worked. Where as if I pass below object "f" as
the argument instead of lambda expression"t->t_.2". It works.
Function f = new
Function<Tuple2<String,Integer>,Integer>(){@Overridepublic Integer
call(Tuple2<String,Integer> paramT1) throws Exception {return
paramT1._2;}};
May I know what is the right format to express that functions as a lambda
expression.
public static void main(String[] args) {
Function f = new Function<Tuple2<String,Integer>,Integer>(){
@Override
public Integer call(Tuple2<String,Integer> paramT1)
throws Exception {
return paramT1._2;
}
};
JavaStreamingContext ssc = JavaStreamingFactory.getInstance();
JavaReceiverInputDStream<String> lines =
ssc.socketTextStream("localhost", 9999);
JavaDStream<String> words = lines.flatMap(s->{return
Arrays.asList(s.split(" "));});
JavaPairDStream<String,Integer> pairRDD =
words.mapToPair(x->new Tuple2<String,Integer>(x,1));
JavaPairDStream<String,Integer> aggregate =
pairRDD.reduceByKey((x,y)->x+y);
JavaDStream<Integer> con = aggregate.transform(
(Function<JavaPairRDD<String,Integer>,
JavaRDD<Integer>>)pRDD-> pRDD.map(
(Function<Tuple2<String,Integer>,Integer>)t->t._2));
//JavaDStream<Integer> con = aggregate.transform(pRDD->
pRDD.map(f)); It works
con.print();
ssc.start();
ssc.awaitTermination();
}