diff --git a/indexing-service/src/main/java/io/druid/indexing/common/task/AppendTask.java b/indexing-service/src/main/java/io/druid/indexing/common/task/AppendTask.java
index d2a3c93594c..51fb358ac8c 100644
--- a/indexing-service/src/main/java/io/druid/indexing/common/task/AppendTask.java
+++ b/indexing-service/src/main/java/io/druid/indexing/common/task/AppendTask.java
@@ -115,7 +115,7 @@ public class AppendTask extends MergeTaskBase
     return "append";
   }
 
-  private class SegmentToMergeHolder
+  private static class SegmentToMergeHolder
   {
     private final DataSegment segment;
     private final Interval interval;
diff --git a/processing/src/main/java/io/druid/query/groupby/GroupByQueryEngine.java b/processing/src/main/java/io/druid/query/groupby/GroupByQueryEngine.java
index a3cc06c0b9a..341090f3176 100644
--- a/processing/src/main/java/io/druid/query/groupby/GroupByQueryEngine.java
+++ b/processing/src/main/java/io/druid/query/groupby/GroupByQueryEngine.java
@@ -236,7 +236,7 @@ public class GroupByQueryEngine
     }
   }
 
-  private class PositionMaintainer
+  private static class PositionMaintainer
   {
     private final int[] increments;
     private final int increment;
@@ -284,7 +284,7 @@ public class GroupByQueryEngine
     }
   }
 
-  private class RowIterator implements CloseableIterator<Row>
+  private static class RowIterator implements CloseableIterator<Row>
   {
     private final GroupByQuery query;
     private final Cursor cursor;
diff --git a/server/src/main/java/io/druid/server/coordinator/LoadQueuePeon.java b/server/src/main/java/io/druid/server/coordinator/LoadQueuePeon.java
index 7a591862d11..73cdad0726a 100644
--- a/server/src/main/java/io/druid/server/coordinator/LoadQueuePeon.java
+++ b/server/src/main/java/io/druid/server/coordinator/LoadQueuePeon.java
@@ -384,7 +384,7 @@ public class LoadQueuePeon
     }
   }
 
-  private class SegmentHolder
+  private static class SegmentHolder
   {
     private final DataSegment segment;
     private final DataSegmentChangeRequest changeRequest;
@@ -457,4 +457,4 @@ public class LoadQueuePeon
       return changeRequest.toString();
     }
   }
-}
\ No newline at end of file
+}
diff --git a/server/src/main/java/io/druid/server/log/EmittingRequestLogger.java b/server/src/main/java/io/druid/server/log/EmittingRequestLogger.java
index 798978d6d2f..21a8bde1599 100644
--- a/server/src/main/java/io/druid/server/log/EmittingRequestLogger.java
+++ b/server/src/main/java/io/druid/server/log/EmittingRequestLogger.java
@@ -125,7 +125,7 @@ public class EmittingRequestLogger implements RequestLogger
     }
   }
 
-  private class RequestLogEventBuilder implements ServiceEventBuilder
+  private static class RequestLogEventBuilder implements ServiceEventBuilder
   {
     private final String feed;
     private final RequestLogLine requestLogLine;