diff --git a/flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/environment/StreamExecutionEnvironment.java b/flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/environment/StreamExecutionEnvironment.java
index 60b849c99653d13a33e2eb87f92e5d64d4fdfbd9..f009871fd0da501ffdb0a6b37f0d37a4f534893b 100644
--- a/flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/environment/StreamExecutionEnvironment.java
+++ b/flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/environment/StreamExecutionEnvironment.java
@@ -57,11 +57,11 @@ import org.apache.flink.streaming.api.functions.source.FromSplittableIteratorFun
 import org.apache.flink.streaming.api.functions.source.ParallelSourceFunction;
 import org.apache.flink.streaming.api.functions.source.SocketTextStreamFunction;
 import org.apache.flink.streaming.api.functions.source.SourceFunction;
+import org.apache.flink.streaming.api.functions.source.StatefulSequenceSource;
 import org.apache.flink.streaming.api.graph.StreamGraph;
 import org.apache.flink.streaming.api.operators.StreamOperator;
 import org.apache.flink.streaming.api.operators.StreamSource;
 import org.apache.flink.types.StringValue;
-import org.apache.flink.util.NumberSequenceIterator;
 import org.apache.flink.util.SplittableIterator;
 
 import java.io.File;
@@ -399,8 +399,10 @@ public abstract class StreamExecutionEnvironment {
 	// --------------------------------------------------------------------------------------------
 
 	/**
-	 * Creates a new data stream that contains a sequence of numbers. The data stream will be created with parallelism
-	 * one, so the order of the elements is guaranteed.
+	 * Creates a new data stream that contains a sequence of numbers. This is a parallel source,
+	 * if you manually set the parallelism to {@code 1}
+	 * (using {@link org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator.setParallelism()})
+	 * the generated sequence of elements is in order.
 	 *
 	 * @param from
 	 * 		The number to start at (inclusive)
@@ -412,22 +414,7 @@ public abstract class StreamExecutionEnvironment {
 		if (from > to) {
 			throw new IllegalArgumentException("Start of sequence must not be greater than the end");
 		}
-		return fromCollection(new NumberSequenceIterator(from, to), BasicTypeInfo.LONG_TYPE_INFO, "Sequence Source");
-	}
-
-	/**
-	 * Creates a new data stream that contains a sequence of numbers. The data stream will be created in parallel, so
-	 * there is no guarantee about the oder of the elements.
-	 *
-	 * @param from
-	 * 		The number to start at (inclusive)
-	 * @param to
-	 * 		The number to stop at (inclusive)
-	 * @return A data stream, containing all number in the [from, to] interval
-	 */
-	public DataStreamSource<Long> generateParallelSequence(long from, long to) {
-		return fromParallelCollection(new NumberSequenceIterator(from, to), BasicTypeInfo.LONG_TYPE_INFO, "Parallel " +
-				"Sequence Source");
+		return addSource(new StatefulSequenceSource(from, to), "Sequence Source");
 	}
 
 	/**
diff --git a/flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/functions/source/StatefulSequenceSource.java b/flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/functions/source/StatefulSequenceSource.java
new file mode 100644
index 0000000000000000000000000000000000000000..e2133633c9b8f7533d543ec9cfcd6c308ddab945
--- /dev/null
+++ b/flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/functions/source/StatefulSequenceSource.java
@@ -0,0 +1,88 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.flink.streaming.api.functions.source;
+
+
+import org.apache.flink.api.common.functions.RuntimeContext;
+import org.apache.flink.streaming.api.checkpoint.Checkpointed;
+
+/**
+ * A stateful streaming source that emits each number from a given interval exactly once,
+ * possibly in parallel.
+ */
+public class StatefulSequenceSource extends RichParallelSourceFunction<Long> implements Checkpointed<Long> {
+	private static final long serialVersionUID = 1L;
+
+	private final long start;
+	private final long end;
+
+	private long collected;
+
+	private volatile boolean isRunning = true;
+
+	/**
+	 * Creates a source that emits all numbers from the given interval exactly once.
+	 *
+	 * @param start Start of the range of numbers to emit.
+	 * @param end End of the range of numbers to emit.
+	 */
+	public StatefulSequenceSource(long start, long end) {
+		this.start = start;
+		this.end = end;
+		this.collected = 0;
+	}
+
+	@Override
+	public void run(SourceContext<Long> ctx) throws Exception {
+		final Object checkpointLock = ctx.getCheckpointLock();
+
+		RuntimeContext context = getRuntimeContext();
+
+		final long stepSize = context.getNumberOfParallelSubtasks();
+		final long congruence = start + context.getIndexOfThisSubtask();
+
+		final long toCollect =
+				((end - start + 1) % stepSize > (congruence - start)) ?
+					((end - start + 1) / stepSize + 1) :
+					((end - start + 1) / stepSize);
+
+		while (isRunning && collected < toCollect) {
+
+			synchronized (checkpointLock) {
+				ctx.collect(collected * stepSize + congruence);
+				collected++;
+			}
+		}
+	}
+
+	@Override
+	public void cancel() {
+		isRunning = false;
+	}
+
+	@Override
+	public Long snapshotState(long checkpointId, long checkpointTimestamp) throws Exception {
+		return collected;
+	}
+
+	@Override
+	public void restoreState(Long state) {
+		collected = state;
+	}
+
+}
diff --git a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/DataStreamTest.java b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/DataStreamTest.java
index 58f7ebae1232244feac5ed6f7bdf5112f6fd4bac..ac04ce8c2ab6bd556e4e09d3b284195e41de1e2d 100644
--- a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/DataStreamTest.java
+++ b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/DataStreamTest.java
@@ -295,7 +295,7 @@ public class DataStreamTest {
 		} catch (IllegalArgumentException success) {
 		}
 
-		DataStreamSource<Long> parallelSource = env.generateParallelSequence(0, 0);
+		DataStreamSource<Long> parallelSource = env.generateSequence(0, 0);
 		assertEquals(7, graph.getStreamNode(parallelSource.getId()).getParallelism());
 
 		parallelSource.setParallelism(3);
diff --git a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/SourceFunctionTest.java b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/SourceFunctionTest.java
index 1bfb13a6e228c455d0c7c618a64f75a94ac29b9e..7a78205ea606bea5ac432ba97c5d1e6db0bacb65 100644
--- a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/SourceFunctionTest.java
+++ b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/SourceFunctionTest.java
@@ -24,7 +24,8 @@ import java.util.Arrays;
 import java.util.List;
 
 import org.apache.flink.streaming.api.functions.source.FromElementsFunction;
-import org.apache.flink.streaming.util.MockSource;
+import org.apache.flink.streaming.api.functions.source.StatefulSequenceSource;
+import org.apache.flink.streaming.util.SourceFunctionUtil;
 import org.junit.Test;
 
 public class SourceFunctionTest {
@@ -32,19 +33,29 @@ public class SourceFunctionTest {
 	@Test
 	public void fromElementsTest() throws Exception {
 		List<Integer> expectedList = Arrays.asList(1, 2, 3);
-		List<Integer> actualList = MockSource.createAndExecute(new FromElementsFunction<Integer>(1,
-				2, 3));
+		List<Integer> actualList = SourceFunctionUtil.runSourceFunction(new FromElementsFunction<Integer>(
+				1,
+				2,
+				3));
 		assertEquals(expectedList, actualList);
 	}
 
 	@Test
 	public void fromCollectionTest() throws Exception {
 		List<Integer> expectedList = Arrays.asList(1, 2, 3);
-		List<Integer> actualList = MockSource.createAndExecute(new FromElementsFunction<Integer>(
+		List<Integer> actualList = SourceFunctionUtil.runSourceFunction(new FromElementsFunction<Integer>(
 				Arrays.asList(1, 2, 3)));
 		assertEquals(expectedList, actualList);
 	}
 
+	@Test
+	public void generateSequenceTest() throws Exception {
+		List<Long> expectedList = Arrays.asList(1L, 2L, 3L, 4L, 5L, 6L, 7L);
+		List<Long> actualList = SourceFunctionUtil.runSourceFunction(new StatefulSequenceSource(1,
+				7));
+		assertEquals(expectedList, actualList);
+	}
+
 	@Test
 	public void socketTextStreamTest() throws Exception {
 		// TODO: does not work because we cannot set the internal socket anymore
diff --git a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/StreamExecutionEnvironmentTest.java b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/StreamExecutionEnvironmentTest.java
index c4a3b6973977c67922a605b8f8c5e9c3d58a6064..7373276d21061593f7142d5d0f178112326c95f7 100644
--- a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/StreamExecutionEnvironmentTest.java
+++ b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/StreamExecutionEnvironmentTest.java
@@ -22,7 +22,6 @@ import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
 import java.util.Arrays;
-import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
 
@@ -32,9 +31,9 @@ import org.apache.flink.streaming.api.datastream.DataStream;
 import org.apache.flink.streaming.api.datastream.DataStreamSource;
 import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
 import org.apache.flink.streaming.api.functions.source.FromElementsFunction;
-import org.apache.flink.streaming.api.functions.source.FromIteratorFunction;
 import org.apache.flink.streaming.api.functions.source.FromSplittableIteratorFunction;
 import org.apache.flink.streaming.api.functions.source.SourceFunction;
+import org.apache.flink.streaming.api.functions.source.StatefulSequenceSource;
 import org.apache.flink.streaming.api.graph.StreamGraph;
 import org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator;
 import org.apache.flink.streaming.api.operators.StreamOperator;
@@ -73,33 +72,12 @@ public class StreamExecutionEnvironmentTest {
 				plan.contains("\"contents\":\"Parallel Collection Source\",\"parallelism\":4"));
 	}
 
-	@Test
-	public void testGenerateSequenceParallelism() throws Exception {
-		StreamExecutionEnvironment env = new TestStreamEnvironment(PARALLELISM, MEMORYSIZE);
-		boolean seenExpectedException = false;
-
-		try {
-			DataStream<Long> dataStream1 = env.generateSequence(0, 0).setParallelism(4);
-		} catch (IllegalArgumentException e) {
-			seenExpectedException = true;
-		}
-
-		DataStream<Long> dataStream2 = env.generateParallelSequence(0, 0).setParallelism(4);
-
-		String plan = env.getExecutionPlan();
-
-		assertTrue("Expected Exception for setting parallelism was not thrown.", seenExpectedException);
-		assertTrue("Parallelism for dataStream1 is not right.",
-				plan.contains("\"contents\":\"Sequence Source\",\"parallelism\":1"));
-		assertTrue("Parallelism for dataStream2 is not right.",
-				plan.contains("\"contents\":\"Parallel Sequence Source\",\"parallelism\":4"));
-	}
-
 	@Test
 	public void testSources() {
 		StreamExecutionEnvironment env = new TestStreamEnvironment(PARALLELISM, MEMORYSIZE);
 
 		SourceFunction<Integer> srcFun = new SourceFunction<Integer>() {
+			private static final long serialVersionUID = 1L;
 
 			@Override
 			public void run(SourceContext<Integer> ctx) throws Exception {
@@ -110,21 +88,18 @@ public class StreamExecutionEnvironmentTest {
 			}
 		};
 		DataStreamSource<Integer> src1 = env.addSource(srcFun);
-		assertEquals(srcFun, getFunctionForDataSource(src1));
+		assertEquals(srcFun, getFunctionFromDataSource(src1));
 
 		List<Long> list = Arrays.asList(0L, 1L, 2L);
 
 		DataStreamSource<Long> src2 = env.generateSequence(0, 2);
-		assertTrue(getFunctionForDataSource(src2) instanceof FromIteratorFunction);
+		assertTrue(getFunctionFromDataSource(src2) instanceof StatefulSequenceSource);
 
 		DataStreamSource<Long> src3 = env.fromElements(0L, 1L, 2L);
-		assertTrue(getFunctionForDataSource(src3) instanceof FromElementsFunction);
+		assertTrue(getFunctionFromDataSource(src3) instanceof FromElementsFunction);
 
 		DataStreamSource<Long> src4 = env.fromCollection(list);
-		assertTrue(getFunctionForDataSource(src4) instanceof FromElementsFunction);
-
-		DataStreamSource<Long> src5 = env.generateParallelSequence(0, 2);
-		assertTrue(getFunctionForDataSource(src5) instanceof FromSplittableIteratorFunction);
+		assertTrue(getFunctionFromDataSource(src4) instanceof FromElementsFunction);
 	}
 
 	/////////////////////////////////////////////////////////////
@@ -132,15 +107,15 @@ public class StreamExecutionEnvironmentTest {
 	/////////////////////////////////////////////////////////////
 
 
-	private static StreamOperator<?> getOperatorForDataStream(DataStream<?> dataStream) {
+	private static StreamOperator<?> getOperatorFromDataStream(DataStream<?> dataStream) {
 		StreamExecutionEnvironment env = dataStream.getExecutionEnvironment();
 		StreamGraph streamGraph = env.getStreamGraph();
 		return streamGraph.getStreamNode(dataStream.getId()).getOperator();
 	}
 
-	private static <T> SourceFunction<T> getFunctionForDataSource(DataStreamSource<T> dataStreamSource) {
+	private static <T> SourceFunction<T> getFunctionFromDataSource(DataStreamSource<T> dataStreamSource) {
 		AbstractUdfStreamOperator<?, ?> operator =
-				(AbstractUdfStreamOperator<?, ?>) getOperatorForDataStream(dataStreamSource);
+				(AbstractUdfStreamOperator<?, ?>) getOperatorFromDataStream(dataStreamSource);
 		return (SourceFunction<T>) operator.getUserFunction();
 	}
 
diff --git a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/collector/DirectedOutputTest.java b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/collector/DirectedOutputTest.java
index 56b6ae85b7aad33c4646bcb4d54861834816753a..fc3e36fb3753c9ca40e7b2f65f82a719a63efca3 100644
--- a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/collector/DirectedOutputTest.java
+++ b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/collector/DirectedOutputTest.java
@@ -101,7 +101,7 @@ public class DirectedOutputTest {
 		TestListResultSink<Long> evenAndOddSink = new TestListResultSink<Long>();
 		TestListResultSink<Long> allSink = new TestListResultSink<Long>();
 
-		SplitDataStream<Long> source = env.generateParallelSequence(1, 11).split(new MyOutputSelector());
+		SplitDataStream<Long> source = env.generateSequence(1, 11).split(new MyOutputSelector());
 		source.select(EVEN).addSink(evenSink);
 		source.select(ODD, TEN).addSink(oddAndTenSink);
 		source.select(EVEN, ODD).addSink(evenAndOddSink);
diff --git a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/complex/ComplexIntegrationTest.java b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/complex/ComplexIntegrationTest.java
index 421d4ac14926a1a67084c5866412bcff8b2f2401..54337783e006391f44494ee8cfba08ad42bef0a0 100644
--- a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/complex/ComplexIntegrationTest.java
+++ b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/complex/ComplexIntegrationTest.java
@@ -207,6 +207,11 @@ public class ComplexIntegrationTest extends StreamingMultipleProgramsTestBase {
 				"16937\n" + "11927\n" + "9973\n" + "14431\n" + "19507\n" + "12497\n" + "17497\n" + "14983\n" +
 				"19997\n";
 
+		expected1 = "541\n" + "1223\n" + "1987\n" + "2741\n" + "3571\n" + "10939\n" + "4409\n" +
+				"5279\n" + "11927\n" + "6133\n" + "6997\n" + "12823\n" + "7919\n" + "8831\n" +
+				"13763\n" + "9733\n" + "9973\n" + "14759\n" + "15671\n" + "16673\n" + "17659\n" +
+				"18617\n" + "19697\n" + "19997\n";
+
 		for (int i = 2; i < 100; i++) {
 			expected2 += "(" + i + "," + 20000 / i + ")\n";
 		}
@@ -217,11 +222,15 @@ public class ComplexIntegrationTest extends StreamingMultipleProgramsTestBase {
 		expected2 += "(" + 20000 + "," + 1 + ")";
 
 		StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
-		
+
+		// set to parallelism 1 because otherwise we don't know which elements go to which parallel
+		// count-window.
+		env.setParallelism(1);
+
 		env.setBufferTimeout(0);
 
-		DataStream<Long> sourceStream31 = env.generateParallelSequence(1, 10000);
-		DataStream<Long> sourceStream32 = env.generateParallelSequence(10001, 20000);
+		DataStream<Long> sourceStream31 = env.generateSequence(1, 10000);
+		DataStream<Long> sourceStream32 = env.generateSequence(10001, 20000);
 
 		sourceStream31.filter(new PrimeFilterFunction())
 				.window(Count.of(100))
@@ -299,14 +308,18 @@ public class ComplexIntegrationTest extends StreamingMultipleProgramsTestBase {
 		//Turning on and off chaining
 
 		expected1 = "1\n" + "2\n" + "2\n" + "3\n" + "3\n" + "3\n" + "4\n" + "4\n" + "4\n" + "4\n" + "5\n" + "5\n" +
-				"5\n" + "5\n" + "5\n" + "1\n" + "3\n" + "3\n" + "4\n" + "5\n" + "5\n" + "6\n" + "8\n" + "9\n" + "10\n" +
-				"12\n" + "15\n" + "16\n" + "20\n" + "25\n";
+				"5\n" + "5\n" + "5\n" + "1\n" + "3\n" + "5\n" + "8\n" + "11\n" + "14\n" + "18\n" + "22\n" + "26\n" +
+				"30\n" + "35\n" + "40\n" + "45\n" + "50\n" + "55\n";
 
 		StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
+
+		// Set to parallelism 1 to make it deterministic, otherwise, it is not clear which
+		// elements will go to which parallel instance of the fold
+		env.setParallelism(1);
 		
 		env.setBufferTimeout(0);
 
-		DataStream<Long> dataStream51 = env.generateParallelSequence(1, 5)
+		DataStream<Long> dataStream51 = env.generateSequence(1, 5)
 				.map(new MapFunction<Long, Long>() {
 
 					@Override
@@ -346,6 +359,8 @@ public class ComplexIntegrationTest extends StreamingMultipleProgramsTestBase {
 		});
 
 
+		dataStream53.union(dataStream52).print();
+
 		dataStream53.union(dataStream52)
 				.writeAsText(resultPath1, FileSystem.WriteMode.OVERWRITE);
 
diff --git a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/operators/ProjectTest.java b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/operators/ProjectTest.java
index c09afeea93a988b662ccb6b7be9e8110cac78a21..d9cc607fb4d26e77a3cebeec780d84c12e15ce56 100644
--- a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/operators/ProjectTest.java
+++ b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/operators/ProjectTest.java
@@ -92,7 +92,7 @@ public class ProjectTest implements Serializable {
 
 		StreamExecutionEnvironment env = new TestStreamEnvironment(1, MEMORY_SIZE);
 
-		env.generateParallelSequence(1, 10).map(new MapFunction<Long, Tuple3<Long, Character, Double>>() {
+		env.generateSequence(1, 10).map(new MapFunction<Long, Tuple3<Long, Character, Double>>() {
 				@Override
 				public Tuple3<Long, Character, Double> map(Long value) throws Exception {
 					return new Tuple3<Long, Character, Double>(value, 'c', value.doubleValue());
diff --git a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/streamtask/StreamVertexTest.java b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/streamtask/StreamVertexTest.java
index 9085034805dcc5b324f0ea9e026a37924d8283ce..f45125b9c6bd037a4efe28ae6b232a27586567cf 100644
--- a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/streamtask/StreamVertexTest.java
+++ b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/api/streamtask/StreamVertexTest.java
@@ -158,7 +158,7 @@ public class StreamVertexTest {
 		StreamExecutionEnvironment env = new TestStreamEnvironment(SOURCE_PARALELISM, MEMORYSIZE);
 
 		DataStream<String> fromStringElements = env.fromElements("aa", "bb", "cc");
-		DataStream<Long> generatedSequence = env.generateParallelSequence(0, 3);
+		DataStream<Long> generatedSequence = env.generateSequence(0, 3);
 
 		fromStringElements.connect(generatedSequence).map(new CoMap()).addSink(new SetSink());
 
diff --git a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/util/MockSource.java b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/util/SourceFunctionUtil.java
similarity index 65%
rename from flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/util/MockSource.java
rename to flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/util/SourceFunctionUtil.java
index 5bf3b61a8a0b15dceab2d1ee137a425464ef7181..5cc534693ca858fb72985b731fdc6c5639e1460b 100644
--- a/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/util/MockSource.java
+++ b/flink-staging/flink-streaming/flink-streaming-core/src/test/java/org/apache/flink/streaming/util/SourceFunctionUtil.java
@@ -20,17 +20,27 @@ package org.apache.flink.streaming.util;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.functions.RichFunction;
+import org.apache.flink.api.common.functions.RuntimeContext;
 import org.apache.flink.configuration.Configuration;
+import org.apache.flink.runtime.operators.testutils.MockEnvironment;
+import org.apache.flink.runtime.operators.testutils.MockInputSplitProvider;
 import org.apache.flink.streaming.api.functions.source.RichSourceFunction;
 import org.apache.flink.streaming.api.functions.source.SourceFunction;
+import org.apache.flink.streaming.runtime.tasks.StreamingRuntimeContext;
 import org.apache.flink.util.Collector;
 
-public class MockSource<T> {
+public class SourceFunctionUtil<T> {
 
-	public static <T> List<T> createAndExecute(SourceFunction<T> sourceFunction) throws Exception {
+	public static <T> List<T> runSourceFunction(SourceFunction<T> sourceFunction) throws Exception {
 		List<T> outputs = new ArrayList<T>();
-		if (sourceFunction instanceof RichSourceFunction) {
-			((RichSourceFunction<T>) sourceFunction).open(new Configuration());
+		if (sourceFunction instanceof RichFunction) {
+			RuntimeContext runtimeContext =  new StreamingRuntimeContext("MockTask", new MockEnvironment(3 * 1024 * 1024, new MockInputSplitProvider(), 1024), null,
+					new ExecutionConfig());
+			((RichFunction) sourceFunction).setRuntimeContext(runtimeContext);
+
+			((RichFunction) sourceFunction).open(new Configuration());
 		}
 		try {
 			final Collector<T> collector = new MockOutput<T>(outputs);
diff --git a/flink-staging/flink-streaming/flink-streaming-scala/src/main/scala/org/apache/flink/streaming/api/scala/StreamExecutionEnvironment.scala b/flink-staging/flink-streaming/flink-streaming-scala/src/main/scala/org/apache/flink/streaming/api/scala/StreamExecutionEnvironment.scala
index 008ad6c7240423fd02a2e6cc80fbe26a7b77db6e..7371c9115fe01341afc33891aa806ed2d8f47cd7 100644
--- a/flink-staging/flink-streaming/flink-streaming-scala/src/main/scala/org/apache/flink/streaming/api/scala/StreamExecutionEnvironment.scala
+++ b/flink-staging/flink-streaming/flink-streaming-scala/src/main/scala/org/apache/flink/streaming/api/scala/StreamExecutionEnvironment.scala
@@ -232,22 +232,12 @@ class StreamExecutionEnvironment(javaEnv: JavaEnv) {
   // --------------------------------------------------------------------------------------------
 
   /**
-   * Creates a new DataStream that contains a sequence of numbers.
-   *
-   * Note that this operation will result in a non-parallel data source, i.e. a data source with
-   * a parallelism of one.
+   * Creates a new DataStream that contains a sequence of numbers. This source is a parallel source.
+   * If you manually set the parallelism to `1` the emitted elements are in order.
    */
   def generateSequence(from: Long, to: Long): DataStream[Long] = {
-    new DataStream[java.lang.Long](javaEnv.generateSequence(from, to)).
-      asInstanceOf[DataStream[Long]]
-  }
-
-  /**
-   * Creates a new DataStream that contains a sequence of numbers in a parallel fashion.
-   */
-  def generateParallelSequence(from: Long, to: Long): DataStream[Long] = {
-    new DataStream[java.lang.Long](javaEnv.generateParallelSequence(from, to)).
-      asInstanceOf[DataStream[Long]]
+    new DataStream[java.lang.Long](javaEnv.generateSequence(from, to))
+      .asInstanceOf[DataStream[Long]]
   }
 
   /**
diff --git a/flink-staging/flink-streaming/flink-streaming-scala/src/test/scala/org/apache/flink/streaming/api/scala/DataStreamTest.scala b/flink-staging/flink-streaming/flink-streaming-scala/src/test/scala/org/apache/flink/streaming/api/scala/DataStreamTest.scala
index 5e348eb6d2f71adcebbba24e3f07a616631b457e..7746bf5642ea9d7c59a7892dcf7bfea4ad713299 100644
--- a/flink-staging/flink-streaming/flink-streaming-scala/src/test/scala/org/apache/flink/streaming/api/scala/DataStreamTest.scala
+++ b/flink-staging/flink-streaming/flink-streaming-scala/src/test/scala/org/apache/flink/streaming/api/scala/DataStreamTest.scala
@@ -228,7 +228,7 @@ class DataStreamTest {
     assert(7 == graph.getStreamNode(windowed.getId).getParallelism)
     assert(7 == graph.getStreamNode(sink.getId).getParallelism)
 
-    val parallelSource = env.generateParallelSequence(0, 0)
+    val parallelSource = env.generateSequence(0, 0)
 
     assert(7 == graph.getStreamNode(parallelSource.getId).getParallelism)
 
diff --git a/flink-tests/src/test/java/org/apache/flink/test/recovery/ProcessFailureStreamingRecoveryITCase.java b/flink-tests/src/test/java/org/apache/flink/test/recovery/ProcessFailureStreamingRecoveryITCase.java
index 626b1d1faa693bcf237b98840c08087cd78a6fe5..f153eb7bda6b187e126a1c966d4cb6e2decf055f 100644
--- a/flink-tests/src/test/java/org/apache/flink/test/recovery/ProcessFailureStreamingRecoveryITCase.java
+++ b/flink-tests/src/test/java/org/apache/flink/test/recovery/ProcessFailureStreamingRecoveryITCase.java
@@ -29,6 +29,7 @@ import java.util.UUID;
 import org.apache.commons.io.FileUtils;
 import org.apache.flink.api.common.functions.MapFunction;
 import org.apache.flink.api.common.functions.RichMapFunction;
+import org.apache.flink.api.common.functions.RuntimeContext;
 import org.apache.flink.configuration.ConfigConstants;
 import org.apache.flink.configuration.Configuration;
 import org.apache.flink.runtime.state.FileStateHandle;
@@ -126,7 +127,7 @@ public class ProcessFailureStreamingRecoveryITCase extends AbstractProcessFailur
 		public void run(SourceContext<Long> sourceCtx) throws Exception {
 			final Object checkpointLock = sourceCtx.getCheckpointLock();
 
-			StreamingRuntimeContext runtimeCtx = (StreamingRuntimeContext) getRuntimeContext();
+			RuntimeContext runtimeCtx = getRuntimeContext();
 
 			final long stepSize = runtimeCtx.getNumberOfParallelSubtasks();
 			final long congruence = runtimeCtx.getIndexOfThisSubtask();