diff --git a/plugin/src/main/java/org/elasticsearch/xpack/graph/action/TransportGraphExploreAction.java b/plugin/src/main/java/org/elasticsearch/xpack/graph/action/TransportGraphExploreAction.java
index 5275a01b516..ce51762d3a4 100644
--- a/plugin/src/main/java/org/elasticsearch/xpack/graph/action/TransportGraphExploreAction.java
+++ b/plugin/src/main/java/org/elasticsearch/xpack/graph/action/TransportGraphExploreAction.java
@@ -351,7 +351,7 @@ public class TransportGraphExploreAction extends HandledTransportAction<GraphExp
                             // There were no terms from the previous phase that needed pursuing
                             continue;
                         }
-                        List<org.elasticsearch.search.aggregations.bucket.terms.Terms.Bucket> buckets = lastWaveTerms.getBuckets();
+                        List<? extends Terms.Bucket> buckets = lastWaveTerms.getBuckets();
                         for (org.elasticsearch.search.aggregations.bucket.terms.Terms.Bucket lastWaveTerm : buckets) {
                             Vertex fromVertex = getVertex(lastVr.fieldName(), lastWaveTerm.getKeyAsString());
                             for (int k = 0; k < currentHop.getNumberVertexRequests(); k++) {
@@ -469,7 +469,7 @@ public class TransportGraphExploreAction extends HandledTransportAction<GraphExp
                         if (lastWaveTerms == null) {
                             continue;
                         }
-                        List<org.elasticsearch.search.aggregations.bucket.terms.Terms.Bucket> buckets = lastWaveTerms.getBuckets();
+                        List<? extends Terms.Bucket> buckets = lastWaveTerms.getBuckets();
                         for (org.elasticsearch.search.aggregations.bucket.terms.Terms.Bucket lastWaveTerm : buckets) {
                             for (int k = 0; k < currentHop.getNumberVertexRequests(); k++) {
                                 VertexRequest vr = currentHop.getVertexRequest(k);
@@ -676,7 +676,7 @@ public class TransportGraphExploreAction extends HandledTransportAction<GraphExp
                                 }
                             } else {
                                 Terms terms = sample.getAggregations().get("field" + j);
-                                List<org.elasticsearch.search.aggregations.bucket.terms.Terms.Bucket> buckets = terms.getBuckets();
+                                List<? extends Terms.Bucket> buckets = terms.getBuckets();
                                 for (org.elasticsearch.search.aggregations.bucket.terms.Terms.Bucket bucket : buckets) {
                                     double signalWeight = bucket.getDocCount() / totalSignalStrength;
                                     addVertex(vr.fieldName(), bucket.getKeyAsString(), signalWeight, currentHopNumber, 0, 0);
@@ -702,7 +702,7 @@ public class TransportGraphExploreAction extends HandledTransportAction<GraphExp
                             } else {
                                 // Signal is based on popularity (number of documents)
                                 Terms terms = sample.getAggregations().get("field" + i);
-                                List<org.elasticsearch.search.aggregations.bucket.terms.Terms.Bucket> buckets = terms.getBuckets();
+                                List<? extends Terms.Bucket> buckets = terms.getBuckets();
                                 for (org.elasticsearch.search.aggregations.bucket.terms.Terms.Bucket bucket : buckets) {
                                     totalSignalStrength += bucket.getDocCount();
                                 }
diff --git a/plugin/src/test/java/org/elasticsearch/xpack/ml/datafeed/extractor/aggregation/AggregationTestUtils.java b/plugin/src/test/java/org/elasticsearch/xpack/ml/datafeed/extractor/aggregation/AggregationTestUtils.java
index 55d09a63d8b..7c6dd937bdd 100644
--- a/plugin/src/test/java/org/elasticsearch/xpack/ml/datafeed/extractor/aggregation/AggregationTestUtils.java
+++ b/plugin/src/test/java/org/elasticsearch/xpack/ml/datafeed/extractor/aggregation/AggregationTestUtils.java
@@ -61,6 +61,7 @@ public final class AggregationTestUtils {
         return singleValue;
     }
 
+    @SuppressWarnings("unchecked")
     static Terms createTerms(String name, Term... terms) {
         Terms termsAgg = mock(Terms.class);
         when(termsAgg.getName()).thenReturn(name);
@@ -79,7 +80,7 @@ public final class AggregationTestUtils {
             }
             buckets.add(bucket);
         }
-        when(termsAgg.getBuckets()).thenReturn(buckets);
+        when((List<Terms.Bucket>) termsAgg.getBuckets()).thenReturn(buckets);
         return termsAgg;
     }