Fix incorrect nullness in FlinkJobInvoker and JobInvoker

Author: kennknowles

runners/flink/src/main/java/org/apache/beam/runners/flink/FlinkJobInvoker.java

@@ -17,6 +17,7 @@
  */
 package org.apache.beam.runners.flink;
 
+import static org.apache.beam.sdk.util.Preconditions.checkStateNotNull;
 import static org.apache.beam.sdk.util.construction.resources.PipelineResources.detectClassPathResourcesToStage;
 
 import java.util.UUID;
@@ -31,14 +32,10 @@
 import org.apache.beam.vendor.grpc.v1p60p1.com.google.protobuf.Struct;
 import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Strings;
 import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.util.concurrent.ListeningExecutorService;
-import org.checkerframework.checker.nullness.qual.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /** Job Invoker for the {@link FlinkRunner}. */
-@SuppressWarnings({
-  "nullness" // TODO(https://github.com/apache/beam/issues/20497)
-})
 public class FlinkJobInvoker extends JobInvoker {
   private static final Logger LOG = LoggerFactory.getLogger(FlinkJobInvoker.class);
 
@@ -57,7 +54,7 @@ protected FlinkJobInvoker(FlinkJobServerDriver.FlinkServerConfiguration serverCo
   protected JobInvocation invokeWithExecutor(
       RunnerApi.Pipeline pipeline,
       Struct options,
-      @Nullable String retrievalToken,
+      String retrievalToken,
       ListeningExecutorService executorService) {
 
     // TODO: How to make Java/Python agree on names of keys and their values?
@@ -74,20 +71,22 @@ protected JobInvocation invokeWithExecutor(
 
     PortablePipelineOptions portableOptions = flinkOptions.as(PortablePipelineOptions.class);
 
+    ClassLoader thisClassLoader =
+        checkStateNotNull(
+            FlinkJobInvoker.class.getClassLoader(),
+            "FlinkJobInvoker class loader is null - this means it was loaded by the bootstrap classloader, which should be impossible");
+
     PortablePipelineRunner pipelineRunner;
     if (Strings.isNullOrEmpty(portableOptions.getOutputExecutablePath())) {
       pipelineRunner =
           new FlinkPipelineRunner(
               flinkOptions,
               serverConfig.getFlinkConfDir(),
-              detectClassPathResourcesToStage(
-                  FlinkJobInvoker.class.getClassLoader(), flinkOptions));
+              detectClassPathResourcesToStage(thisClassLoader, flinkOptions));
     } else {
       pipelineRunner = new PortablePipelineJarCreator(FlinkPipelineRunner.class);
     }
 
-    flinkOptions.setRunner(null);
-
     LOG.info("Invoking job {} with pipeline runner {}", invocationId, pipelineRunner);
     return createJobInvocation(
         invocationId, retrievalToken, executorService, pipeline, flinkOptions, pipelineRunner);

runners/java-job-service/src/main/java/org/apache/beam/runners/jobsubmission/JobInvoker.java

@@ -20,7 +20,6 @@
 import java.io.IOException;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ThreadFactory;
-import javax.annotation.Nullable;
 import org.apache.beam.model.pipeline.v1.RunnerApi;
 import org.apache.beam.vendor.grpc.v1p60p1.com.google.protobuf.Struct;
 import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.util.concurrent.ListeningExecutorService;
@@ -39,11 +38,11 @@ public abstract class JobInvoker {
   protected abstract JobInvocation invokeWithExecutor(
       RunnerApi.Pipeline pipeline,
       Struct options,
-      @Nullable String retrievalToken,
+      String retrievalToken,
       ListeningExecutorService executorService)
       throws IOException;
 
-  JobInvocation invoke(RunnerApi.Pipeline pipeline, Struct options, @Nullable String retrievalToken)
+  JobInvocation invoke(RunnerApi.Pipeline pipeline, Struct options, String retrievalToken)
       throws IOException {
     return invokeWithExecutor(pipeline, options, retrievalToken, this.executorService);
   }