When i use the examples, I have met the problem :Ambiguous method call. Both via(SimpleFunction<KV<String,Long>,String>) in Mapelements and
via (SerializableFunction) in Mapelements math
so why the examples have that problem?

Following get start tutorial, got error whether JDK or OpenJDK with Cloud Shell:

mvn compile exec:java
-Dexec.mainClass=com.google.cloud.dataflow.examples.WordCount
-Dexec.args="--project=alpha-life-line
--stagingLocation=word-count
--runner=BlockingDataflowPipelineRunner"

[INFO] --- exec-maven-plugin:1.5.0:java (default-cli) @ first-dataflow ---
[WARNING]
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:294)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.RuntimeException: Failed to construct instance from factory method BlockingDataflowPipelineRunner#fromOptions(interface com.google.cloud.dataflow.sdk.options.PipelineOptions)
at com.google.cloud.dataflow.sdk.util.InstanceBuilder.buildFromMethod(InstanceBuilder.java:233)
at com.google.cloud.dataflow.sdk.util.InstanceBuilder.build(InstanceBuilder.java:162)
at com.google.cloud.dataflow.sdk.runners.PipelineRunner.fromOptions(PipelineRunner.java:57)
at com.google.cloud.dataflow.sdk.Pipeline.create(Pipeline.java:134)
at com.example.WordCount.main(WordCount.java:193)
... 6 more
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.google.cloud.dataflow.sdk.util.InstanceBuilder.buildFromMethod(InstanceBuilder.java:222)
... 10 more
Caused by: java.lang.IllegalArgumentException:
at com.google.api.client.json.JsonParser.parseValue(JsonParser.java:889)
at com.google.api.client.json.JsonParser.parseArray(JsonParser.java:648)
at com.google.api.client.json.JsonParser.parseArray(JsonParser.java:628)
at com.google.api.client.json.JsonParser.parseArray(JsonParser.java:597)
at com.google.api.client.json.JsonParser.parseArray(JsonParser.java:577)
at com.google.api.client.googleapis.auth.oauth2.CloudShellCredential.executeRefreshToken(CloudShellCredential.java:88)
at com.google.api.client.auth.oauth2.Credential.refreshToken(Credential.java:489)
at com.google.api.client.auth.oauth2.Credential.intercept(Credential.java:217)
at com.google.cloud.hadoop.util.ChainingHttpRequestInitializer$2.intercept(ChainingHttpRequestInitializer.java:98)
at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:859)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:419)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:352)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.execute(AbstractGoogleClientRequest.java:469)
at com.google.cloud.hadoop.util.ResilientOperation$AbstractGoogleClientRequestExecutor.call(ResilientOperation.java:166)
at com.google.cloud.hadoop.util.ResilientOperation.retry(ResilientOperation.java:66)
at com.google.cloud.dataflow.sdk.util.GcsUtil.bucketExists(GcsUtil.java:325)
at com.google.cloud.dataflow.sdk.util.GcsUtil.bucketExists(GcsUtil.java:312)
at com.google.cloud.dataflow.sdk.util.DataflowPathValidator.verifyPathIsAccessible(DataflowPathValidator.java:79)
at com.google.cloud.dataflow.sdk.util.DataflowPathValidator.validateOutputFilePrefixSupported(DataflowPathValidator.java:62)
at com.google.cloud.dataflow.sdk.runners.DataflowPipelineRunner.fromOptions(DataflowPipelineRunner.java:255)
at com.google.cloud.dataflow.sdk.runners.BlockingDataflowPipelineRunner.fromOptions(BlockingDataflowPipelineRunner.java:82)
... 15 more
Caused by: java.lang.IllegalArgumentException: expected numeric type but got class java.lang.String
at com.google.api.client.json.JsonParser.parseValue(JsonParser.java:844)
... 35 more
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
at java.lang.reflect.Method.invoke(Method.java:606)
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 10.595 s
[INFO] Finished at: 2016-06-10T16:52:53+08:00
[INFO] Final Memory: 14M/33M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.5.0:java (default-cli) on project first-dataflow: An exception occured while executing the Java class. nu
ll: InvocationTargetException: Failed to construct instance from factory method BlockingDataflowPipelineRunner#fromOptions(interface com.google.cloud.dataflow.sdk.options.Pip
elineOptions): IllegalArgumentException: expected numeric type but got class java.lang.String -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

SDK version 1.9.0 hasn't been pushed to maven central yet so commit 5a81bf1 breaks the build. Is there another repository where I can find dataflow-java-sdk in the mean time?

Hi there,
I'm trying to run the DatastoreWordCount from the cookbook examples and encountered this exception.
I was hoping to get some help with this issue.

Stack Trace:

2016-02-15T17:43:36.674Z: Error: (2edb046603c29179): com.google.api.services.datastore.client.DatastoreException: Backend Error
at com.google.api.services.datastore.client.RemoteRpc.makeException(RemoteRpc.java:115)
at com.google.api.services.datastore.client.RemoteRpc.call(RemoteRpc.java:81)
at com.google.api.services.datastore.client.BaseDatastoreFactory$RemoteRpc.call(BaseDatastoreFactory.java:41)
at com.google.api.services.datastore.client.Datastore.commit(Datastore.java:85)
at com.google.cloud.dataflow.sdk.io.DatastoreIO$DatastoreWriter.flushBatch(DatastoreIO.java:768)
at com.google.cloud.dataflow.sdk.io.DatastoreIO$DatastoreWriter.write(DatastoreIO.java:726)
at com.google.cloud.dataflow.sdk.io.DatastoreIO$DatastoreWriter.write(DatastoreIO.java:668)
at com.google.cloud.dataflow.sdk.io.Write$Bound$2.processElement(Write.java:168)
Caused by: com.google.api.client.http.HttpResponseException: 503 Service Unavailable
Backend Error
at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:1054)
at com.google.api.services.datastore.client.RemoteRpc.call(RemoteRpc.java:78)
at com.google.api.services.datastore.client.BaseDatastoreFactory$RemoteRpc.call(BaseDatastoreFactory.java:41)
at com.google.api.services.datastore.client.Datastore.commit(Datastore.java:85)
at com.google.cloud.dataflow.sdk.io.DatastoreIO$DatastoreWriter.flushBatch(DatastoreIO.java:768)
at com.google.cloud.dataflow.sdk.io.DatastoreIO$DatastoreWriter.write(DatastoreIO.java:726)
at com.google.cloud.dataflow.sdk.io.DatastoreIO$DatastoreWriter.write(DatastoreIO.java:668)
at com.google.cloud.dataflow.sdk.io.Write$Bound$2.processElement(Write.java:168)
at com.google.cloud.dataflow.sdk.util.DoFnRunner.invokeProcessElement(DoFnRunner.java:189)
at com.google.cloud.dataflow.sdk.util.DoFnRunner.processElement(DoFnRunner.java:171)
at com.google.cloud.dataflow.sdk.runners.worker.ParDoFnBase.processElement(ParDoFnBase.java:213)
at com.google.cloud.dataflow.sdk.util.common.worker.ParDoOperation.process(ParDoOperation.java:53)
at com.google.cloud.dataflow.sdk.util.common.worker.OutputReceiver.process(OutputReceiver.java:52)
at com.google.cloud.dataflow.sdk.runners.worker.ParDoFnBase$1.output(ParDoFnBase.java:174)
at com.google.cloud.dataflow.sdk.util.DoFnRunner$DoFnContext.outputWindowedValue(DoFnRunner.java:333)
at com.google.cloud.dataflow.sdk.util.DoFnRunner$DoFnProcessContext.output(DoFnRunner.java:487)
at com.google.cloud.dataflow.examples.cookbook.DatastoreWordCount$CreateEntityFn.processElement(DatastoreWordCount.java:148)
at com.google.cloud.dataflow.sdk.util.DoFnRunner.invokeProcessElement(DoFnRunner.java:189)
at com.google.cloud.dataflow.sdk.util.DoFnRunner.processElement(DoFnRunner.java:171)
at com.google.cloud.dataflow.sdk.runners.worker.ParDoFnBase.processElement(ParDoFnBase.java:213)
at com.google.cloud.dataflow.sdk.util.common.worker.ParDoOperation.process(ParDoOperation.java:53)
at com.google.cloud.dataflow.sdk.util.common.worker.OutputReceiver.process(OutputReceiver.java:52)
at com.google.cloud.dataflow.sdk.util.common.worker.ReadOperation.runReadLoop(ReadOperation.java:223)
at com.google.cloud.dataflow.sdk.util.common.worker.ReadOperation.start(ReadOperation.java:169)
at com.google.cloud.dataflow.sdk.util.common.worker.MapTaskExecutor.execute(MapTaskExecutor.java:69)
at com.google.cloud.dataflow.sdk.runners.worker.DataflowWorker.executeWork(DataflowWorker.java:254)
at com.google.cloud.dataflow.sdk.runners.worker.DataflowWorker.doWork(DataflowWorker.java:191)
at com.google.cloud.dataflow.sdk.runners.worker.DataflowWorker.getAndPerformWork(DataflowWorker.java:144)
at com.google.cloud.dataflow.sdk.runners.worker.DataflowWorkerHarness$WorkerThread.doWork(DataflowWorkerHarness.java:180)
at com.google.cloud.dataflow.sdk.runners.worker.DataflowWorkerHarness$WorkerThread.call(DataflowWorkerHarness.java:161)
at com.google.cloud.dataflow.sdk.runners.worker.DataflowWorkerHarness$WorkerThread.call(DataflowWorkerHarness.java:148)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

Thanks!

The names of all Runners have been shortened by removing Pipeline:

--runner=BlockingDataflowPipelineRunner is now --runner=DataflowRunner

Replaced BlockingDataflowPipelineRunner with PipelineResult.waitToFinish()

Ideally we'd update the imports in a script.

(this is filed as BEAM-442 for Beam but the scope & timing of the issue probably means it deserves an issue here as well)

From http://stackoverflow.com/questions/38317428/how-do-i-resolve-java-lang-nosuchmethoderror-com-google-api-services-dataflow-m

The above StackOverflow question illuminates the fact that this repository is not a demonstration of proper project configuration, but only code. It is probably quite useful to have a starter project that actually has the dependencies set up correctly, not referencing the Dataflow SDK parent pom, so users can clone it and get started.

I was following the instruction and run the mvn command within GCP Cloud Shell but got the "package com.google.cloud.dataflow.examples.common does not exist" error. Do I need to do any additional configuration?

The readme links seem to have been relocated.
https://github.com/GoogleCloudPlatform/DataflowJavaSDK-examples/tree/master/src/main/java/com/google/cloud/dataflow/examples/complete