Demonstrates bug in remote api transactional task handling

RemoteApiExample.java

package com.remoteapi.bug;

import com.google.appengine.api.datastore.*;
import com.google.appengine.api.taskqueue.Queue;
import com.google.appengine.api.taskqueue.QueueFactory;
import com.google.appengine.api.taskqueue.TaskOptions;
import com.google.appengine.tools.remoteapi.RemoteApiInstaller;
import com.google.appengine.tools.remoteapi.RemoteApiOptions;
import java.io.IOException;

public class RemoteApiExample {
	public static void main(String[] args) throws IOException, EntityNotFoundException {
		RemoteApiOptions options = new RemoteApiOptions()
				.server("remoteapi-transaction-bug.appspot.com", 443)
				.useApplicationDefaultCredential();
		RemoteApiInstaller installer = new RemoteApiInstaller();
		installer.install(options);
		try {
			insertIntoDatasore();
		} finally {
			installer.uninstall();
		}
	}

	private static void insertIntoDatasore() throws EntityNotFoundException {
		DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
		final Queue defaultQueue = QueueFactory.getDefaultQueue();
		Transaction txn = datastore.beginTransaction();
		try {
			Entity employee = new Entity(KeyFactory.createKey("Employee", "Joe"));
			datastore.put(txn,employee);

			defaultQueue.add(txn, TaskOptions.Builder.withUrl("/"));
			txn.commit();
		} finally {
			if (txn.isActive()) {
				txn.rollback();
			}
		}

	}
}

stacktrace.txt

Exception in thread "main" com.google.appengine.api.taskqueue.TransactionalTaskException
	at com.google.appengine.api.taskqueue.QueueApiHelper.translateError(QueueApiHelper.java:102)
	at com.google.appengine.api.taskqueue.QueueApiHelper.translateError(QueueApiHelper.java:159)
	at com.google.appengine.api.taskqueue.QueueApiHelper$1.convertException(QueueApiHelper.java:55)
	at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:96)
	at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:88)
	at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:88)
	at com.google.appengine.api.taskqueue.QueueApiHelper.getInternal(QueueApiHelper.java:78)
	at com.google.appengine.api.taskqueue.QueueImpl.add(QueueImpl.java:433)
	at com.remoteapi.bug.RemoteApiExample.insertIntoDatasore(RemoteApiExample.java:33)
	at com.remoteapi.bug.RemoteApiExample.main(RemoteApiExample.java:19)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: java.lang.IllegalArgumentException: 
	at com.google.appengine.api.datastore.DatastoreApiHelper.translateError(DatastoreApiHelper.java:54)
	at com.google.appengine.api.taskqueue.QueueApiHelper.translateError(QueueApiHelper.java:104)
	... 14 more

Process finished with exit code 1