[FLINK-6691][checkstyle] Add separate block for scala imports

flink-metrics/flink-metrics-jmx/src/test/java/org/apache/flink/runtime/jobmanager/JMXJobManagerMetricTest.java

@@ -33,10 +33,6 @@
 
 import org.junit.Assert;
 import org.junit.Test;
-import scala.concurrent.Await;
-import scala.concurrent.Future;
-import scala.concurrent.duration.Deadline;
-import scala.concurrent.duration.FiniteDuration;
 
 import javax.management.MBeanServer;
 import javax.management.ObjectName;
@@ -46,6 +42,11 @@
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
+import scala.concurrent.Await;
+import scala.concurrent.Future;
+import scala.concurrent.duration.Deadline;
+import scala.concurrent.duration.FiniteDuration;
+
 import static org.junit.Assert.assertEquals;
 
 /**

flink-streaming-java/src/main/java/org/apache/flink/streaming/util/typeutils/FieldAccessor.java

@@ -28,15 +28,15 @@
 import org.apache.flink.api.java.typeutils.runtime.FieldSerializer;
 import org.apache.flink.api.java.typeutils.runtime.TupleSerializerBase;
 
-import scala.Product;
-
 import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.io.Serializable;
 import java.lang.reflect.Array;
 import java.lang.reflect.Field;
 
+import scala.Product;
+
 import static org.apache.flink.util.Preconditions.checkNotNull;
 
 

flink-streaming-java/src/test/java/org/apache/flink/streaming/runtime/tasks/OneInputStreamTaskTest.java

@@ -60,8 +60,6 @@
 
 import org.junit.Assert;
 import org.junit.Test;
-import scala.concurrent.duration.Deadline;
-import scala.concurrent.duration.FiniteDuration;
 
 import java.io.Serializable;
 import java.util.ArrayList;
@@ -76,6 +74,9 @@
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.TimeUnit;
 
+import scala.concurrent.duration.Deadline;
+import scala.concurrent.duration.FiniteDuration;
+
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;

flink-streaming-java/src/test/java/org/apache/flink/streaming/runtime/tasks/StreamTaskTest.java

@@ -100,11 +100,6 @@
 import org.powermock.core.classloader.annotations.PowerMockIgnore;
 import org.powermock.core.classloader.annotations.PrepareForTest;
 import org.powermock.modules.junit4.PowerMockRunner;
-import scala.concurrent.Await;
-import scala.concurrent.Future;
-import scala.concurrent.duration.Deadline;
-import scala.concurrent.duration.FiniteDuration;
-import scala.concurrent.impl.Promise;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -122,6 +117,12 @@
 import java.util.concurrent.RunnableFuture;
 import java.util.concurrent.TimeUnit;
 
+import scala.concurrent.Await;
+import scala.concurrent.Future;
+import scala.concurrent.duration.Deadline;
+import scala.concurrent.duration.FiniteDuration;
+import scala.concurrent.impl.Promise;
+
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;

tools/maven/strict-checkstyle.xml

@@ -197,8 +197,8 @@ This file is based on the checkstyle file of Apache Beam.
  <module name="ImportOrder">
  <!-- Checks for out of order import statements. -->
  <property name="severity" value="error"/>
- <!-- Flink imports first, then other imports, then javax and java imports, then static imports. -->
- <property name="groups" value="org.apache.flink,*,javax,java"/>
+ <!-- Flink imports first, then other imports, then javax, java and scala imports, then static imports. -->
+ <property name="groups" value="org.apache.flink,*,javax,java,scala"/>
  <property name="separated" value="true"/>
  <property name="sortStaticImportsAlphabetically" value="true"/>
  <property name="option" value="bottom"/>