Alex/Gleb can someone of you please add the detailed instructions that worked for you in some section of cwiki.
I have the impression that this will benefit us all at some point.


On Tue, Feb 18, 2020 at 9:46 AM Alex Van Boxel <> wrote:
Thanks everyone. This really helped a lot. I used Gleb's tip to make it work. Successfully validated my Pull Requests against Dataflow!

_/ Alex Van Boxel

On Mon, Feb 17, 2020 at 11:55 PM Brian Hulette <> wrote:
I think if you update past [1] this will go away. We had to build a new worker to use with builds on master after [2]. You should be fine running from master as long as you aren't using a commit between those two (merge commits are 6818560 and bde3031, respectively). Setting the Dataflow worker jar would work too.

On Mon, Feb 17, 2020 at 2:14 AM Gleb Kanterov <> wrote:
You need to pass custom Dataflow worker jar. One of the ways of doing that is adding it as a dependency, and using following code snippet:


Coming with the disclaimer that it isn't for production :)

On Mon, Feb 17, 2020 at 8:34 AM Alex Van Boxel <> wrote:
Yes, running it manually with the normal parameters as I do for production Dataflow. I'm probably a bit ignorant on that, and I probably need to provide my own worker.

Thanks for the hint... I'll dive into that.

_/ Alex Van Boxel

On Mon, Feb 17, 2020 at 8:16 AM Reuven Lax <> wrote:
Are you running things manually? This probably means you are using an out-of-date Dataflow worker. I believe that all tests on Jenkins will build the Dataflow worker from head to prevent exactly this problem.

On Sun, Feb 16, 2020 at 11:10 PM Alex Van Boxel <> wrote:
Digging further in the traces, it seems like a result of changes to the model:

Caused by: java.lang.ClassNotFoundException: org.apache.beam.model.pipeline.v1.StandardWindowFns$SessionsPayload$Enum

I see changes by Lukasz Cwik. Will this be a problem for the release?

_/ Alex Van Boxel

On Sun, Feb 16, 2020 at 12:11 PM Alex Van Boxel <> wrote:

I'm testing my own PR's against Dataflow, something I've done in the past with success seem to fail now. I get this error:

java.lang.NoClassDefFoundError: Could not initialize class

Am I doing something wrong?

_/ Alex Van Boxel