java.lang.IllegalStateException: Unable to return a default Coder in dataflow 2.X

Question

I have a simple pipeline in dataflow 2.1 sdk. Which reads data from pubsub then applies a DoFn to it.

PCollection<MyClass> e = streamData.apply("ToE", ParDo.of(new MyDoFNClass()));

Getting below error on this pipeline:

java.lang.IllegalStateException: Unable to return a default Coder for ToEvents/ParMultiDo(MyDoFNClass).out0 [PCollection]. Correct one of the following root causes: No Coder has been manually specified; you may do so using .setCoder(). Inferring a Coder from the CoderRegistry failed: Unable to provide a Coder for com.X.X.model.MyClass.

MyDoFn class is below:

@DefaultCoder(AvroCoder.class)

public class MyClass{

    public long id;
    public HashMap<String,HashSet<String>> a;

    @SerializedName("a")
    public Integer Id;
    @SerializedName("ae")
    public String ae;
}

Answer 1

Found the solution just neeeded to add implements Serializable to MyClass

@DefaultCoder(AvroCoder.class)

public class MyClass implements Serializable {

public long id;
public HashMap<String,HashSet<String>> a;

@SerializedName("a")
public Integer Id;
@SerializedName("ae")
public String ae;
}