Task fails in Spark with ClassNotFoundException

Question

I am trying to write a simple java program which will read data from Cassandra via Spark. I am doing this at POC level. My code looks like this

String keyspace = "newkspace1";
String tablename = "newtable5";
public static void main(String[] args) 
    {
        SparkConf conf = new SparkConf();
        conf.setAppName("Cassandra Demo");
        conf.setMaster("spark://ct-0094:7077");
        conf.set("spark.cassandra.connection.host", "192.168.50.124");
        conf.set("spark.cassandra.connection.native.port", "9041");
        conf.set("spark.cassandra.connection.rpc.port", "9160");
        PerformerClass app = new PerformerClass(conf);
        app.run();
    } 
private void run() 
    {
        JavaSparkContext sc = new JavaSparkContext(conf);
        showResults(sc);
        sc.stop();
    }
 private void showResults(JavaSparkContext sc) 
    {
        CassandraJavaPairRDD<Integer, Integer> rdd1 = javaFunctions(sc)
                .cassandraTable(keyspace, tablename, mapColumnTo(Integer.class), mapColumnTo(Integer.class))
                .select("keyval", "rangefield");


        List<Integer> lst = rdd1.keys().toArray();
        for(Integer l : lst)
        {
            System.out.println(l);
        }
    }

When I ran the above code, I got the following exceptions (Stack trace pasted below)

15/01/15 19:22:41 WARN scheduler.TaskSetManager: Lost task 1.0 in stage 0.0 (TID 1, ct-0094): java.lang.ClassNotFoundException: com.datastax.spark.connector.rdd.partitioner.CassandraPartition at java.net.URLClassLoader$1.run(URLClassLoader.java:372) at java.net.URLClassLoader$1.run(URLClassLoader.java:361) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:360) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:340) at org.apache.spark.serializer.JavaDeserializationStream$$anon$1.resolveClass(JavaSerializer.scala:59) [...]

What am I missing?

abi_pat abi_pat · Accepted Answer · 2015-01-15T15:30:39

I solved it myself by going through some blogs.

Actually the jar of the program must be included in the program itself like

JavaSparkContext sc = new JavaSparkContext(conf);
sc.addJar("./target/SparkPOC-0.0.1-SNAPSHOT-jar-with-dependencies.jar");

This solves the problem. But everytime before running your code, you have to Maven Install (that is create the jar) your code and then run it. I am still looking for the better approach where these steps can be avoided.

Task fails in Spark with ClassNotFoundException

1 Answers