Change Terms.Bucket to an interface (#24492)

This commit changes the Terms.Bucket abstract class to an interface, so
that it's easier for the Java High Level Rest Client to provide its own
implementation.

In its current state, the Terms.Bucket abstract class inherits from
InternalMultiBucketAggregation.InternalBucket which forces subclasses to
implement Writeable and exposes a public getProperty() method that relies
on InternalAggregation. This two points make it difficult for the Java
High Level Rest Client to implement the Terms and Terms.Bucket correctly.
This is also different from other MultiBucketsAggregation like Range
which are pure interfaces.

Changing Terms.Bucket to an interface causes a method clashes for the
`getBuckets()` method in InternalTerms. This is because:
 - InternalTerms implements Terms which declared a
 `List<Terms.Bucket> getBuckets()` method
 - InternalTerms extends InternalMultiBucketAggregation which declares a
 `List<? extends InternalBucket> getBuckets()` method
 - both overrides the MultiBucketsAggregation
 `List<? extends Bucket> getBuckets()` method

 There was no clashes before this change because Terms.Bucket extends
 InternalBucket and conformed to both declaration. With Terms.Bucket now
 an interface, the getBuckets() method in the Terms interface is changed
 to avoid method clash. This is a breaking change in the Java API but
 it's a straightforward change and the Terms multi bucket aggregation
 interface is also more coherent with the other Range, Histogram,
 Filters, AdjacencyMatrix etc that all return a `List<? extends Bucket>`.

31 files changed, 107 insertions, 105 deletions

diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/CombiIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/CombiIT.java
index 7517e98ff2..c38552ae25 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/CombiIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/CombiIT.java
@@ -30,7 +30,7 @@ import org.elasticsearch.search.aggregations.bucket.terms.Terms;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.hamcrest.Matchers;
 
-import java.util.Collection;
+import java.util.List;
 
 import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.elasticsearch.search.aggregations.AggregationBuilders.histogram;
@@ -95,7 +95,7 @@ public class CombiIT extends ESIntegTestCase {
 
         Terms terms = aggs.get("values");
         assertNotNull(terms);
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(values.size()));
         for (Terms.Bucket bucket : buckets) {
             values.remove(((Number) bucket.getKey()).intValue());
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/EquivalenceIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/EquivalenceIT.java
index 00f82dfbe4..6c08c16972 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/EquivalenceIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/EquivalenceIT.java
@@ -485,10 +485,10 @@ public class EquivalenceIT extends ESIntegTestCase {
     }
 
     private void assertEquals(Terms t1, Terms t2) {
-        List<Terms.Bucket> t1Buckets = t1.getBuckets();
-        List<Terms.Bucket> t2Buckets = t1.getBuckets();
+        List<? extends Terms.Bucket> t1Buckets = t1.getBuckets();
+        List<? extends Terms.Bucket> t2Buckets = t1.getBuckets();
         assertEquals(t1Buckets.size(), t2Buckets.size());
-        for (Iterator<Terms.Bucket> it1 = t1Buckets.iterator(), it2 = t2Buckets.iterator(); it1.hasNext(); ) {
+        for (Iterator<? extends Terms.Bucket> it1 = t1Buckets.iterator(), it2 = t2Buckets.iterator(); it1.hasNext(); ) {
             final Terms.Bucket b1 = it1.next();
             final Terms.Bucket b2 = it2.next();
             assertEquals(b1.getDocCount(), b2.getDocCount());
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/DiversifiedSamplerIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/DiversifiedSamplerIT.java
index 9af28806fe..c8803b7e79 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/DiversifiedSamplerIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/DiversifiedSamplerIT.java
@@ -32,6 +32,7 @@ import org.elasticsearch.search.aggregations.metrics.max.Max;
 import org.elasticsearch.test.ESIntegTestCase;
 
 import java.util.Collection;
+import java.util.List;
 
 import static org.elasticsearch.cluster.metadata.IndexMetaData.SETTING_NUMBER_OF_REPLICAS;
 import static org.elasticsearch.cluster.metadata.IndexMetaData.SETTING_NUMBER_OF_SHARDS;
@@ -108,7 +109,7 @@ public class DiversifiedSamplerIT extends ESIntegTestCase {
                 ).execute().actionGet();
         assertSearchResponse(response);
         Terms genres = response.getAggregations().get("genres");
-        Collection<Bucket> genreBuckets = genres.getBuckets();
+        Collection<? extends Bucket> genreBuckets = genres.getBuckets();
         // For this test to be useful we need >1 genre bucket to compare
         assertThat(genreBuckets.size(), greaterThan(1));
         double lastMaxPrice = asc ? Double.MIN_VALUE : Double.MAX_VALUE;
@@ -141,7 +142,7 @@ public class DiversifiedSamplerIT extends ESIntegTestCase {
         assertSearchResponse(response);
         Sampler sample = response.getAggregations().get("sample");
         Terms authors = sample.getAggregations().get("authors");
-        Collection<Bucket> testBuckets = authors.getBuckets();
+        List<? extends Bucket> testBuckets = authors.getBuckets();
 
         for (Terms.Bucket testBucket : testBuckets) {
             assertThat(testBucket.getDocCount(), lessThanOrEqualTo((long) NUM_SHARDS * MAX_DOCS_PER_AUTHOR));
@@ -162,11 +163,11 @@ public class DiversifiedSamplerIT extends ESIntegTestCase {
                 .addAggregation(rootTerms).execute().actionGet();
         assertSearchResponse(response);
         Terms genres = response.getAggregations().get("genres");
-        Collection<Bucket> genreBuckets = genres.getBuckets();
+        List<? extends Bucket> genreBuckets = genres.getBuckets();
         for (Terms.Bucket genreBucket : genreBuckets) {
             Sampler sample = genreBucket.getAggregations().get("sample");
             Terms authors = sample.getAggregations().get("authors");
-            Collection<Bucket> testBuckets = authors.getBuckets();
+            List<? extends Bucket> testBuckets = authors.getBuckets();
 
             for (Terms.Bucket testBucket : testBuckets) {
                 assertThat(testBucket.getDocCount(), lessThanOrEqualTo((long) NUM_SHARDS * MAX_DOCS_PER_AUTHOR));
@@ -195,7 +196,7 @@ public class DiversifiedSamplerIT extends ESIntegTestCase {
         Sampler sample = genreSample.getAggregations().get("sample");
 
         Terms genres = sample.getAggregations().get("genres");
-        Collection<Bucket> testBuckets = genres.getBuckets();
+        List<? extends Bucket> testBuckets = genres.getBuckets();
         for (Terms.Bucket testBucket : testBuckets) {
             assertThat(testBucket.getDocCount(), lessThanOrEqualTo((long) NUM_SHARDS * MAX_DOCS_PER_GENRE));
         }
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/DoubleTermsIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/DoubleTermsIT.java
index cf28541121..ca106721fc 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/DoubleTermsIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/DoubleTermsIT.java
@@ -842,7 +842,7 @@ public class DoubleTermsIT extends AbstractTermsTestCase {
         assertThat(tags.getName(), equalTo("num_tags"));
         assertThat(tags.getBuckets().size(), equalTo(2));
 
-        Iterator<Terms.Bucket> iters = tags.getBuckets().iterator();
+        Iterator<? extends Terms.Bucket> iters = tags.getBuckets().iterator();
 
         Terms.Bucket tag = iters.next();
         assertThat(tag, notNullValue());
@@ -883,7 +883,7 @@ public class DoubleTermsIT extends AbstractTermsTestCase {
         assertThat(tags.getName(), equalTo("tags"));
         assertThat(tags.getBuckets().size(), equalTo(2));
 
-        Iterator<Terms.Bucket> iters = tags.getBuckets().iterator();
+        Iterator<? extends Terms.Bucket> iters = tags.getBuckets().iterator();
 
         // the max for "1" is 2
         // the max for "0" is 4
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/LongTermsIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/LongTermsIT.java
index 6793768a91..a54dc3e2f5 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/LongTermsIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/LongTermsIT.java
@@ -854,7 +854,7 @@ public class LongTermsIT extends AbstractTermsTestCase {
         assertThat(tags.getName(), equalTo("num_tags"));
         assertThat(tags.getBuckets().size(), equalTo(2));
 
-        Iterator<Terms.Bucket> iters = tags.getBuckets().iterator();
+        Iterator<? extends Terms.Bucket> iters = tags.getBuckets().iterator();
 
         Terms.Bucket tag = iters.next();
         assertThat(tag, notNullValue());
@@ -893,7 +893,7 @@ public class LongTermsIT extends AbstractTermsTestCase {
         assertThat(tags.getName(), equalTo("tags"));
         assertThat(tags.getBuckets().size(), equalTo(2));
 
-        Iterator<Terms.Bucket> iters = tags.getBuckets().iterator();
+        Iterator<? extends Terms.Bucket> iters = tags.getBuckets().iterator();
 
         // the max for "1" is 2
         // the max for "0" is 4
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/MinDocCountIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/MinDocCountIT.java
index 7307b756e3..e1e8f1ba66 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/MinDocCountIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/MinDocCountIT.java
@@ -161,8 +161,8 @@ public class MinDocCountIT extends AbstractTermsTestCase {
     // check that terms2 is a subset of terms1
     private void assertSubset(Terms terms1, Terms terms2, long minDocCount, int size, String include) {
         final Matcher matcher = include == null ? null : Pattern.compile(include).matcher("");;
-        final Iterator<Terms.Bucket> it1 = terms1.getBuckets().iterator();
-        final Iterator<Terms.Bucket> it2 = terms2.getBuckets().iterator();
+        final Iterator<? extends Terms.Bucket> it1 = terms1.getBuckets().iterator();
+        final Iterator<? extends Terms.Bucket> it2 = terms2.getBuckets().iterator();
         int size2 = 0;
         while (it1.hasNext()) {
             final Terms.Bucket bucket1 = it1.next();
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SamplerIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SamplerIT.java
index f87b98bc87..ebd078de67 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SamplerIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SamplerIT.java
@@ -31,6 +31,7 @@ import org.elasticsearch.search.aggregations.metrics.max.Max;
 import org.elasticsearch.test.ESIntegTestCase;
 
 import java.util.Collection;
+import java.util.List;
 
 import static org.elasticsearch.cluster.metadata.IndexMetaData.SETTING_NUMBER_OF_REPLICAS;
 import static org.elasticsearch.cluster.metadata.IndexMetaData.SETTING_NUMBER_OF_SHARDS;
@@ -104,7 +105,7 @@ public class SamplerIT extends ESIntegTestCase {
                 ).execute().actionGet();
         assertSearchResponse(response);
         Terms genres = response.getAggregations().get("genres");
-        Collection<Bucket> genreBuckets = genres.getBuckets();
+        List<? extends Bucket> genreBuckets = genres.getBuckets();
         // For this test to be useful we need >1 genre bucket to compare
         assertThat(genreBuckets.size(), greaterThan(1));
         double lastMaxPrice = asc ? Double.MIN_VALUE : Double.MAX_VALUE;
@@ -130,7 +131,7 @@ public class SamplerIT extends ESIntegTestCase {
         assertSearchResponse(response);
         Sampler sample = response.getAggregations().get("sample");
         Terms authors = sample.getAggregations().get("authors");
-        Collection<Bucket> testBuckets = authors.getBuckets();
+        List<? extends Bucket> testBuckets = authors.getBuckets();
 
         long maxBooksPerAuthor = 0;
         for (Terms.Bucket testBucket : testBuckets) {
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/ShardSizeTermsIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/ShardSizeTermsIT.java
index ecc16b85f1..748c5f886f 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/ShardSizeTermsIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/ShardSizeTermsIT.java
@@ -22,8 +22,8 @@ import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.search.aggregations.Aggregator.SubAggCollectionMode;
 import org.elasticsearch.search.aggregations.bucket.terms.Terms;
 
-import java.util.Collection;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import static org.elasticsearch.index.query.QueryBuilders.matchAllQuery;
@@ -43,7 +43,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms  terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3));
         Map<String, Long> expected = new HashMap<>();
         expected.put("1", 8L);
@@ -66,7 +66,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms  terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3));
         Map<String, Long> expected = new HashMap<>();
         expected.put("1", 8L);
@@ -90,7 +90,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3)); // we still only return 3 entries (based on the 'size' param)
         Map<String, Long> expected = new HashMap<>();
         expected.put("1", 8L);
@@ -114,7 +114,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3)); // we still only return 3 entries (based on the 'size' param)
         Map<String, Long> expected = new HashMap<>();
         expected.put("1", 5L);
@@ -137,7 +137,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms  terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3));
         Map<String, Long> expected = new HashMap<>();
         expected.put("1", 8L);
@@ -160,7 +160,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3));
         Map<Integer, Long> expected = new HashMap<>();
         expected.put(1, 8L);
@@ -183,7 +183,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3));
         Map<Integer, Long> expected = new HashMap<>();
         expected.put(1, 8L);
@@ -206,7 +206,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3)); // we still only return 3 entries (based on the 'size' param)
         Map<Integer, Long> expected = new HashMap<>();
         expected.put(1, 8L);
@@ -230,7 +230,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3)); // we still only return 3 entries (based on the 'size' param)
         Map<Integer, Long> expected = new HashMap<>();
         expected.put(1, 5L);
@@ -253,7 +253,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3));
         Map<Integer, Long> expected = new HashMap<>();
         expected.put(1, 8L);
@@ -276,7 +276,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3));
         Map<Integer, Long> expected = new HashMap<>();
         expected.put(1, 8L);
@@ -299,7 +299,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3));
         Map<Integer, Long> expected = new HashMap<>();
         expected.put(1, 8L);
@@ -322,7 +322,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3));
         Map<Integer, Long> expected = new HashMap<>();
         expected.put(1, 8L);
@@ -345,7 +345,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3));
         Map<Integer, Long> expected = new HashMap<>();
         expected.put(1, 5L);
@@ -368,7 +368,7 @@ public class ShardSizeTermsIT extends ShardSizeTestCase {
                 .execute().actionGet();
 
         Terms terms = response.getAggregations().get("keys");
-        Collection<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(3));
         Map<Integer, Long> expected = new HashMap<>();
         expected.put(1, 8L);
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java
index 7fc20908e8..09cec9a458 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java
@@ -438,7 +438,7 @@ public class SignificantTermsSignificanceScoreIT extends ESIntegTestCase {
         assertSearchResponse(response);
         StringTerms classes = response.getAggregations().get("class");
         assertThat(classes.getBuckets().size(), equalTo(2));
-        Iterator<Terms.Bucket> classBuckets = classes.getBuckets().iterator();
+        Iterator<? extends Terms.Bucket> classBuckets = classes.getBuckets().iterator();
 
         Aggregations aggregations = classBuckets.next().getAggregations();
         SignificantTerms sigTerms = aggregations.get("mySignificantTerms");
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/StringTermsIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/StringTermsIT.java
index b5dbcd9085..df69cfcfa9 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/StringTermsIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/StringTermsIT.java
@@ -1012,7 +1012,7 @@ public class StringTermsIT extends AbstractTermsTestCase {
         assertThat(tags.getName(), equalTo("tags"));
         assertThat(tags.getBuckets().size(), equalTo(2));
 
-        Iterator<Terms.Bucket> iters = tags.getBuckets().iterator();
+        Iterator<? extends Terms.Bucket> iters = tags.getBuckets().iterator();
 
         Terms.Bucket tag = iters.next();
         assertThat(tag, notNullValue());
@@ -1054,7 +1054,7 @@ public class StringTermsIT extends AbstractTermsTestCase {
         assertThat(tags.getName(), equalTo("tags"));
         assertThat(tags.getBuckets().size(), equalTo(2));
 
-        Iterator<Terms.Bucket> iters = tags.getBuckets().iterator();
+        Iterator<? extends Terms.Bucket> iters = tags.getBuckets().iterator();
 
         // the max for "more" is 2
         // the max for "less" is 4
@@ -1117,7 +1117,7 @@ public class StringTermsIT extends AbstractTermsTestCase {
         assertThat(tags.getName(), equalTo("tags"));
         assertThat(tags.getBuckets().size(), equalTo(2));
 
-        Iterator<Terms.Bucket> iters = tags.getBuckets().iterator();
+        Iterator<? extends Terms.Bucket> iters = tags.getBuckets().iterator();
 
         // the max for "more" is 2
         // the max for "less" is 4
@@ -1180,7 +1180,7 @@ public class StringTermsIT extends AbstractTermsTestCase {
         assertThat(tags.getName(), equalTo("tags"));
         assertThat(tags.getBuckets().size(), equalTo(2));
 
-        Iterator<Terms.Bucket> iters = tags.getBuckets().iterator();
+        Iterator<? extends Terms.Bucket> iters = tags.getBuckets().iterator();
 
         // the max for "more" is 2
         // the max for "less" is 4
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/TermsDocCountErrorIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/TermsDocCountErrorIT.java
index 9d5ca3afc5..9ed32ca2e7 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/TermsDocCountErrorIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/TermsDocCountErrorIT.java
@@ -177,7 +177,7 @@ public class TermsDocCountErrorIT extends ESIntegTestCase {
         assertThat(testTerms, notNullValue());
         assertThat(testTerms.getName(), equalTo("terms"));
         assertThat(testTerms.getDocCountError(), greaterThanOrEqualTo(0L));
-        Collection<Bucket> testBuckets = testTerms.getBuckets();
+        List<? extends Bucket> testBuckets = testTerms.getBuckets();
         assertThat(testBuckets.size(), lessThanOrEqualTo(size));
         assertThat(accurateTerms.getBuckets().size(), greaterThanOrEqualTo(testBuckets.size()));
 
@@ -211,7 +211,7 @@ public class TermsDocCountErrorIT extends ESIntegTestCase {
         assertThat(testTerms, notNullValue());
         assertThat(testTerms.getName(), equalTo("terms"));
         assertThat(testTerms.getDocCountError(), equalTo(0L));
-        Collection<Bucket> testBuckets = testTerms.getBuckets();
+        List<? extends Bucket> testBuckets = testTerms.getBuckets();
         assertThat(testBuckets.size(), lessThanOrEqualTo(size));
         assertThat(accurateTerms.getBuckets().size(), greaterThanOrEqualTo(testBuckets.size()));
 
@@ -229,7 +229,7 @@ public class TermsDocCountErrorIT extends ESIntegTestCase {
         assertThat(testTerms, notNullValue());
         assertThat(testTerms.getName(), equalTo("terms"));
         assertThat(testTerms.getDocCountError(), equalTo(0L));
-        Collection<Bucket> testBuckets = testTerms.getBuckets();
+        List<? extends Bucket> testBuckets = testTerms.getBuckets();
         assertThat(testBuckets.size(), lessThanOrEqualTo(size));
 
         for (Terms.Bucket testBucket : testBuckets) {
@@ -248,7 +248,7 @@ public class TermsDocCountErrorIT extends ESIntegTestCase {
         assertThat(testTerms, notNullValue());
         assertThat(testTerms.getName(), equalTo("terms"));
         assertThat(testTerms.getDocCountError(),anyOf(equalTo(-1L), equalTo(0L)));
-        Collection<Bucket> testBuckets = testTerms.getBuckets();
+        List<? extends Bucket> testBuckets = testTerms.getBuckets();
         assertThat(testBuckets.size(), lessThanOrEqualTo(size));
         assertThat(accurateTerms.getBuckets().size(), greaterThanOrEqualTo(testBuckets.size()));
 
@@ -988,7 +988,7 @@ public class TermsDocCountErrorIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getDocCountError(), equalTo(46L));
-        List<Bucket> buckets = terms.getBuckets();
+        List<? extends Bucket> buckets = terms.getBuckets();
         assertThat(buckets, notNullValue());
         assertThat(buckets.size(), equalTo(5));
         
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/terms/TermsAggregatorTests.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/terms/TermsAggregatorTests.java
index f2977fd769..1648d8ede9 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/terms/TermsAggregatorTests.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/terms/TermsAggregatorTests.java
@@ -136,7 +136,7 @@ public class TermsAggregatorTests extends AggregatorTestCase {
                 InternalAggregation mergedAggs = internalAgg.doReduce(aggs, ctx);
                 assertTrue(mergedAggs instanceof DoubleTerms);
                 long expected = numLongs + numDoubles;
-                List<Terms.Bucket> buckets = ((DoubleTerms) mergedAggs).getBuckets();
+                List<? extends Terms.Bucket> buckets = ((DoubleTerms) mergedAggs).getBuckets();
                 assertEquals(4, buckets.size());
                 assertEquals("1.0", buckets.get(0).getKeyAsString());
                 assertEquals(expected, buckets.get(0).getDocCount());
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/AvgIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/AvgIT.java
index 2e2aa9657d..b7739d6c81 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/AvgIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/AvgIT.java
@@ -334,7 +334,7 @@ public class AvgIT extends AbstractNumericTestCase {
 
         Terms terms = searchResponse.getAggregations().get("terms");
         assertThat(terms, notNullValue());
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets, notNullValue());
         assertThat(buckets.size(), equalTo(10));
 
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/ExtendedStatsIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/ExtendedStatsIT.java
index 7de7bb0f31..3903dd8b0b 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/ExtendedStatsIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/ExtendedStatsIT.java
@@ -604,7 +604,7 @@ public class ExtendedStatsIT extends AbstractNumericTestCase {
 
         Terms terms = searchResponse.getAggregations().get("terms");
         assertThat(terms, notNullValue());
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets, notNullValue());
         assertThat(buckets.size(), equalTo(10));
 
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/GeoBoundsIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/GeoBoundsIT.java
index e4444571a3..1a97cb4916 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/GeoBoundsIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/GeoBoundsIT.java
@@ -233,7 +233,7 @@ public class GeoBoundsIT extends AbstractGeoTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Bucket> buckets = terms.getBuckets();
+        List<? extends Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(10));
         for (int i = 0; i < 10; i++) {
             Bucket bucket = buckets.get(i);
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/HDRPercentileRanksIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/HDRPercentileRanksIT.java
index 0aef20bca6..5b56e6b7ef 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/HDRPercentileRanksIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/HDRPercentileRanksIT.java
@@ -515,7 +515,7 @@ public class HDRPercentileRanksIT extends AbstractNumericTestCase {
 
         Terms terms = searchResponse.getAggregations().get("terms");
         assertThat(terms, notNullValue());
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets, notNullValue());
         assertThat(buckets.size(), equalTo(10));
 
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/HDRPercentilesIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/HDRPercentilesIT.java
index d3531da925..56fb14402a 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/HDRPercentilesIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/HDRPercentilesIT.java
@@ -506,7 +506,7 @@ public class HDRPercentilesIT extends AbstractNumericTestCase {
 
         Terms terms = searchResponse.getAggregations().get("terms");
         assertThat(terms, notNullValue());
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets, notNullValue());
         assertThat(buckets.size(), equalTo(10));
 
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/MaxIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/MaxIT.java
index 5c9e14c345..03eb9a0923 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/MaxIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/MaxIT.java
@@ -336,7 +336,7 @@ public class MaxIT extends AbstractNumericTestCase {
 
         Terms terms = searchResponse.getAggregations().get("terms");
         assertThat(terms, notNullValue());
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets, notNullValue());
         assertThat(buckets.size(), equalTo(10));
 
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/MinIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/MinIT.java
index 2b517b64fa..cba2ba9eb9 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/MinIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/MinIT.java
@@ -348,7 +348,7 @@ public class MinIT extends AbstractNumericTestCase {
 
         Terms terms = searchResponse.getAggregations().get("terms");
         assertThat(terms, notNullValue());
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets, notNullValue());
         assertThat(buckets.size(), equalTo(10));
 
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/StatsIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/StatsIT.java
index 85db616630..9231f09396 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/StatsIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/StatsIT.java
@@ -455,7 +455,7 @@ public class StatsIT extends AbstractNumericTestCase {
 
         Terms terms = searchResponse.getAggregations().get("terms");
         assertThat(terms, notNullValue());
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets, notNullValue());
         assertThat(buckets.size(), equalTo(10));
 
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/SumIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/SumIT.java
index 1591e6df93..16d345c7b8 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/SumIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/SumIT.java
@@ -333,7 +333,7 @@ public class SumIT extends AbstractNumericTestCase {
 
         Terms terms = searchResponse.getAggregations().get("terms");
         assertThat(terms, notNullValue());
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets, notNullValue());
         assertThat(buckets.size(), equalTo(10));
 
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/TDigestPercentileRanksIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/TDigestPercentileRanksIT.java
index 057731e275..f1943747ce 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/TDigestPercentileRanksIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/TDigestPercentileRanksIT.java
@@ -466,7 +466,7 @@ public class TDigestPercentileRanksIT extends AbstractNumericTestCase {
 
         Terms terms = searchResponse.getAggregations().get("terms");
         assertThat(terms, notNullValue());
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets, notNullValue());
         assertThat(buckets.size(), equalTo(10));
 
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/TDigestPercentilesIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/TDigestPercentilesIT.java
index d81ca004b9..2589e9977a 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/TDigestPercentilesIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/TDigestPercentilesIT.java
@@ -451,7 +451,7 @@ public class TDigestPercentilesIT extends AbstractNumericTestCase {
 
         Terms terms = searchResponse.getAggregations().get("terms");
         assertThat(terms, notNullValue());
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets, notNullValue());
         assertThat(buckets.size(), equalTo(10));
 
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/TopHitsIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/TopHitsIT.java
index aeef44d627..e9b9ae2040 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/TopHitsIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/TopHitsIT.java
@@ -519,9 +519,9 @@ public class TopHitsIT extends ESIntegTestCase {
             SearchHits hits = topHits.getHits();
             assertThat(hits.getTotalHits(), equalTo(10L));
             assertThat(hits.getHits().length, equalTo(3));
-            assertThat((Long) hits.getAt(0).getSortValues()[0], equalTo(higestSortValue));
-            assertThat((Long) hits.getAt(1).getSortValues()[0], equalTo(higestSortValue - 1));
-            assertThat((Long) hits.getAt(2).getSortValues()[0], equalTo(higestSortValue - 2));
+            assertThat(hits.getAt(0).getSortValues()[0], equalTo(higestSortValue));
+            assertThat(hits.getAt(1).getSortValues()[0], equalTo(higestSortValue - 1));
+            assertThat(hits.getAt(2).getSortValues()[0], equalTo(higestSortValue - 2));
             Max max = bucket.getAggregations().get("max_sort");
             assertThat(max.getValue(), equalTo(((Long) higestSortValue).doubleValue()));
             higestSortValue -= 10;
@@ -544,7 +544,7 @@ public class TopHitsIT extends ESIntegTestCase {
         assertThat(terms.getName(), equalTo("terms"));
         assertThat(terms.getBuckets().size(), equalTo(3));
 
-        Iterator<Terms.Bucket> bucketIterator = terms.getBuckets().iterator();
+        Iterator<? extends Terms.Bucket> bucketIterator = terms.getBuckets().iterator();
         Terms.Bucket bucket = bucketIterator.next();
         assertThat(key(bucket), equalTo("b"));
         TopHits topHits = bucket.getAggregations().get("hits");
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/AvgBucketIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/AvgBucketIT.java
index d62e93fa5e..4f6ff0e32e 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/AvgBucketIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/AvgBucketIT.java
@@ -140,7 +140,7 @@ public class AvgBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -182,7 +182,7 @@ public class AvgBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(interval));
 
         double bucketSum = 0;
@@ -223,7 +223,7 @@ public class AvgBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -277,7 +277,7 @@ public class AvgBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -322,7 +322,7 @@ public class AvgBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(0));
 
         InternalSimpleValue avgBucketValue = response.getAggregations().get("avg_bucket");
@@ -349,7 +349,7 @@ public class AvgBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         double aggTermsSum = 0;
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/ExtendedStatsBucketIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/ExtendedStatsBucketIT.java
index d4310e581c..607124ecb1 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/ExtendedStatsBucketIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/ExtendedStatsBucketIT.java
@@ -211,7 +211,7 @@ public class ExtendedStatsBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -262,7 +262,7 @@ public class ExtendedStatsBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(interval));
 
         double bucketSum = 0;
@@ -312,7 +312,7 @@ public class ExtendedStatsBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -375,7 +375,7 @@ public class ExtendedStatsBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -429,7 +429,7 @@ public class ExtendedStatsBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(0));
 
         ExtendedStatsBucket extendedStatsBucketValue = response.getAggregations().get("extended_stats_bucket");
@@ -487,7 +487,7 @@ public class ExtendedStatsBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         double aggTermsSum = 0;
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/MaxBucketIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/MaxBucketIT.java
index aba941ebb4..632f11f7ec 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/MaxBucketIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/MaxBucketIT.java
@@ -149,7 +149,7 @@ public class MaxBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -196,7 +196,7 @@ public class MaxBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(interval));
 
         List<String> maxKeys = new ArrayList<>();
@@ -242,7 +242,7 @@ public class MaxBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -348,7 +348,7 @@ public class MaxBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -397,7 +397,7 @@ public class MaxBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(0));
 
         InternalBucketMetricValue maxBucketValue = response.getAggregations().get("max_bucket");
@@ -425,7 +425,7 @@ public class MaxBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         List<String> maxTermsKeys = new ArrayList<>();
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/MinBucketIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/MinBucketIT.java
index cbd6824b3a..04fdd0c313 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/MinBucketIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/MinBucketIT.java
@@ -146,7 +146,7 @@ public class MinBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -193,7 +193,7 @@ public class MinBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(interval));
 
         List<String> minKeys = new ArrayList<>();
@@ -239,7 +239,7 @@ public class MinBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -298,7 +298,7 @@ public class MinBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -347,7 +347,7 @@ public class MinBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(0));
 
         InternalBucketMetricValue minBucketValue = response.getAggregations().get("min_bucket");
@@ -375,7 +375,7 @@ public class MinBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         List<String> minTermsKeys = new ArrayList<>();
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/PercentilesBucketIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/PercentilesBucketIT.java
index c582c76bd8..e23e544143 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/PercentilesBucketIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/PercentilesBucketIT.java
@@ -145,7 +145,7 @@ public class PercentilesBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -187,7 +187,7 @@ public class PercentilesBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(interval));
 
         double[] values = new double[interval];
@@ -220,7 +220,7 @@ public class PercentilesBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(interval));
 
         double[] values = new double[interval];
@@ -261,7 +261,7 @@ public class PercentilesBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -316,7 +316,7 @@ public class PercentilesBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -361,7 +361,7 @@ public class PercentilesBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(0));
 
         PercentilesBucket percentilesBucketValue = response.getAggregations().get("percentiles_bucket");
@@ -384,7 +384,7 @@ public class PercentilesBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(0));
 
         PercentilesBucket percentilesBucketValue = response.getAggregations().get("percentiles_bucket");
@@ -479,7 +479,7 @@ public class PercentilesBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         double[] values = new double[termsBuckets.size()];
@@ -539,7 +539,7 @@ public class PercentilesBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         double[] values = new double[termsBuckets.size()];
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/StatsBucketIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/StatsBucketIT.java
index c38dc99bdf..231005f1b5 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/StatsBucketIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/StatsBucketIT.java
@@ -147,7 +147,7 @@ public class StatsBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -195,7 +195,7 @@ public class StatsBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(interval));
 
         double bucketSum = 0;
@@ -242,7 +242,7 @@ public class StatsBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -302,7 +302,7 @@ public class StatsBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -353,7 +353,7 @@ public class StatsBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(0));
 
         StatsBucket statsBucketValue = response.getAggregations().get("stats_bucket");
@@ -380,7 +380,7 @@ public class StatsBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         double aggTermsSum = 0;
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/SumBucketIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/SumBucketIT.java
index 0958243004..048dfac864 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/SumBucketIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/SumBucketIT.java
@@ -137,7 +137,7 @@ public class SumBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -176,7 +176,7 @@ public class SumBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(interval));
 
         double bucketSum = 0;
@@ -214,7 +214,7 @@ public class SumBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -265,7 +265,7 @@ public class SumBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         for (int i = 0; i < interval; ++i) {
@@ -307,7 +307,7 @@ public class SumBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> buckets = terms.getBuckets();
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
         assertThat(buckets.size(), equalTo(0));
 
         InternalSimpleValue sumBucketValue = response.getAggregations().get("sum_bucket");
@@ -334,7 +334,7 @@ public class SumBucketIT extends ESIntegTestCase {
         Terms terms = response.getAggregations().get("terms");
         assertThat(terms, notNullValue());
         assertThat(terms.getName(), equalTo("terms"));
-        List<Terms.Bucket> termsBuckets = terms.getBuckets();
+        List<? extends Terms.Bucket> termsBuckets = terms.getBuckets();
         assertThat(termsBuckets.size(), equalTo(interval));
 
         double aggTermsSum = 0;