NPE when calling the Indexer with no indexed entities

package people;
message Person {
 required string name = 1;
}

{
 "_type": "people.Person",
 "name": "katia"
}

6:51:46,457 ERROR (blocking-thread--p3-t5) [org.infinispan.rest.resources.SearchAdminResource] ISPN012022: Error executing MassIndexer java.lang.NullPointerException6:51:46,457 ERROR (blocking-thread--p3-t5) [org.infinispan.rest.resources.SearchAdminResource] ISPN012022: Error executing MassIndexer java.lang.NullPointerException at org.infinispan.query.impl.massindex.IndexUpdater.allJavaClasses(IndexUpdater.java:57) at org.infinispan.query.impl.massindex.DistributedExecutorMassIndexer.lambda$executeInternal$3(DistributedExecutorMassIndexer.java:123) at java.base/java.util.concurrent.CompletableFuture.uniComposeStage(CompletableFuture.java:1106) at java.base/java.util.concurrent.CompletableFuture.thenCompose(CompletableFuture.java:2235) at java.base/java.util.concurrent.CompletableFuture.thenCompose(CompletableFuture.java:143) at org.infinispan.query.impl.massindex.DistributedExecutorMassIndexer.executeInternal(DistributedExecutorMassIndexer.java:117) at org.infinispan.query.impl.massindex.DistributedExecutorMassIndexer.run(DistributedExecutorMassIndexer.java:74) at org.infinispan.rest.resources.SearchAdminResource.runIndexer(SearchAdminResource.java:109) at org.infinispan.rest.resources.SearchAdminResource.reindex(SearchAdminResource.java:59) at org.infinispan.rest.framework.impl.RestDispatcherImpl.dispatch(RestDispatcherImpl.java:75) at org.infinispan.rest.RestRequestHandler.handleRestRequest(RestRequestHandler.java:133) at org.infinispan.rest.RestRequestHandler.lambda$channelRead0$0(RestRequestHandler.java:112) at java.base/java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:859) at java.base/java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:837) at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506) at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1705) at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35) at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1982) at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486) at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1377) at java.base/java.lang.Thread.run(Thread.java:834)