Make some ObjectParsers final (#50471)

We have about 800 `ObjectParsers` in Elasticsearch, about 700 of which
are final. This is *probably* the right way to declare them because in
practice we never mutate them after they are built. And we certainly
don't change the static reference. Anyway, this adds `final` to a bunch
of these parsers, mostly the ones in xpack and their "paired" parsers in
the high level rest client. I picked these just to have somewhere to
break the up the change so it wouldn't be huge.

I found the non-final parsers with this:
```
diff \
  <(find . -type f -name '*.java' -exec grep -iHe 'static.*PARSER\s*=' {} \+ | sort) \
  <(find . -type f -name '*.java' -exec grep -iHe 'static.*final.*PARSER\s*=' {} \+ | sort) \
  2>&1 | grep '^<'
```

client/rest-high-level/src/main/java/org/elasticsearch/client/core/MainResponse.java

@@ -27,8 +27,7 @@ import java.util.Objects;
 
 public class MainResponse {
 
-    @SuppressWarnings("unchecked")
-    private static ConstructingObjectParser<MainResponse, Void> PARSER =
+    private static final ConstructingObjectParser<MainResponse, Void> PARSER =
         new ConstructingObjectParser<>(MainResponse.class.getName(), true,
             args -> {
                  return new MainResponse((String) args[0], (Version) args[1], (String) args[2], (String) args[3], (String) args[4]);

client/rest-high-level/src/main/java/org/elasticsearch/client/ilm/LifecyclePolicy.java

@@ -44,7 +44,7 @@ public class LifecyclePolicy implements ToXContentObject {
     static final ParseField PHASES_FIELD = new ParseField("phases");
 
     @SuppressWarnings("unchecked")
-    public static ConstructingObjectParser<LifecyclePolicy, String> PARSER = new ConstructingObjectParser<>("lifecycle_policy", true,
+    public static final ConstructingObjectParser<LifecyclePolicy, String> PARSER = new ConstructingObjectParser<>("lifecycle_policy", true,
         (a, name) -> {
             List<Phase> phases = (List<Phase>) a[0];
             Map<String, Phase> phaseMap = phases.stream().collect(Collectors.toMap(Phase::getName, Function.identity()));

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/dataframe/explain/FieldSelection.java

@@ -57,7 +57,7 @@ public class FieldSelection implements ToXContentObject {
     }
 
     @SuppressWarnings("unchecked")
-    public static ConstructingObjectParser<FieldSelection, Void> PARSER = new ConstructingObjectParser<>("field_selection", true,
+    public static final ConstructingObjectParser<FieldSelection, Void> PARSER = new ConstructingObjectParser<>("field_selection", true,
         a -> new FieldSelection((String) a[0], new HashSet<>((List<String>) a[1]), (boolean) a[2], (boolean) a[3], (FeatureType) a[4],
             (String) a[5]));
 

client/rest-high-level/src/main/java/org/elasticsearch/client/security/CreateApiKeyResponse.java

@@ -89,7 +89,7 @@ public final class CreateApiKeyResponse {
                 && Objects.equals(expiration, other.expiration);
     }
 
-    static ConstructingObjectParser<CreateApiKeyResponse, Void> PARSER = new ConstructingObjectParser<>("create_api_key_response",
+    static final ConstructingObjectParser<CreateApiKeyResponse, Void> PARSER = new ConstructingObjectParser<>("create_api_key_response",
             args -> new CreateApiKeyResponse((String) args[0], (String) args[1], new SecureString((String) args[2]),
                     (args[3] == null) ? null : Instant.ofEpochMilli((Long) args[3])));
     static {

client/rest-high-level/src/main/java/org/elasticsearch/client/security/GetApiKeyResponse.java

@@ -73,9 +73,10 @@ public final class GetApiKeyResponse {
     }
 
     @SuppressWarnings("unchecked")
-    static ConstructingObjectParser<GetApiKeyResponse, Void> PARSER = new ConstructingObjectParser<>("get_api_key_response", args -> {
-        return (args[0] == null) ? GetApiKeyResponse.emptyResponse() : new GetApiKeyResponse((List<ApiKey>) args[0]);
-    });
+    static final ConstructingObjectParser<GetApiKeyResponse, Void> PARSER = new ConstructingObjectParser<>(
+        "get_api_key_response",
+        args -> { return (args[0] == null) ? GetApiKeyResponse.emptyResponse() : new GetApiKeyResponse((List<ApiKey>) args[0]); }
+    );
     static {
         PARSER.declareObjectArray(optionalConstructorArg(), (p, c) -> ApiKey.fromXContent(p), new ParseField("api_keys"));
     }

client/rest-high-level/src/main/java/org/elasticsearch/client/security/InvalidateApiKeyResponse.java

@@ -74,10 +74,12 @@ public final class InvalidateApiKeyResponse {
     }
 
     @SuppressWarnings("unchecked")
-    static ConstructingObjectParser<InvalidateApiKeyResponse, Void> PARSER = new ConstructingObjectParser<>("invalidate_api_key_response",
-            args -> {
-                return new InvalidateApiKeyResponse((List<String>) args[0], (List<String>) args[1], (List<ElasticsearchException>) args[3]);
-            });
+    static final ConstructingObjectParser<InvalidateApiKeyResponse, Void> PARSER = new ConstructingObjectParser<>(
+        "invalidate_api_key_response",
+        args -> {
+            return new InvalidateApiKeyResponse((List<String>) args[0], (List<String>) args[1], (List<ElasticsearchException>) args[3]);
+        }
+    );
     static {
         PARSER.declareStringArray(constructorArg(), new ParseField("invalidated_api_keys"));
         PARSER.declareStringArray(constructorArg(), new ParseField("previously_invalidated_api_keys"));

client/rest-high-level/src/main/java/org/elasticsearch/client/security/support/ApiKey.java

@@ -127,7 +127,7 @@ public final class ApiKey {
                 && Objects.equals(realm, other.realm);
     }
 
-    static ConstructingObjectParser<ApiKey, Void> PARSER = new ConstructingObjectParser<>("api_key", args -> {
+    static final ConstructingObjectParser<ApiKey, Void> PARSER = new ConstructingObjectParser<>("api_key", args -> {
         return new ApiKey((String) args[0], (String) args[1], Instant.ofEpochMilli((Long) args[2]),
                 (args[3] == null) ? null : Instant.ofEpochMilli((Long) args[3]), (Boolean) args[4], (String) args[5], (String) args[6]);
     });

modules/aggs-matrix-stats/src/main/java/org/elasticsearch/search/aggregations/matrix/stats/ParsedMatrixStats.java

@@ -151,7 +151,7 @@ public class ParsedMatrixStats extends ParsedAggregation implements MatrixStats
         return values.get(fieldName);
     }
 
-    private static ObjectParser<ParsedMatrixStats, Void> PARSER =
+    private static final ObjectParser<ParsedMatrixStats, Void> PARSER =
             new ObjectParser<>(ParsedMatrixStats.class.getSimpleName(), true, ParsedMatrixStats::new);
     static {
         declareAggregationFields(PARSER);

x-pack/plugin/ccr/src/main/java/org/elasticsearch/xpack/ccr/action/ShardFollowTask.java

@@ -44,7 +44,7 @@ public class ShardFollowTask extends ImmutableFollowParameters implements Persis
     private static final ParseField HEADERS = new ParseField("headers");
 
     @SuppressWarnings("unchecked")
-    private static ConstructingObjectParser<ShardFollowTask, Void> PARSER = new ConstructingObjectParser<>(NAME,
+    private static final ConstructingObjectParser<ShardFollowTask, Void> PARSER = new ConstructingObjectParser<>(NAME,
             (a) -> new ShardFollowTask((String) a[0],
                 new ShardId((String) a[1], (String) a[2], (int) a[3]), new ShardId((String) a[4], (String) a[5], (int) a[6]),
                 (Integer) a[7], (Integer) a[8], (Integer) a[9], (Integer) a[10], (ByteSizeValue) a[11], (ByteSizeValue) a[12],

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ilm/LifecyclePolicy.java

@@ -47,7 +47,7 @@ public class LifecyclePolicy extends AbstractDiffable<LifecyclePolicy>
     public static final ParseField PHASES_FIELD = new ParseField("phases");
 
     @SuppressWarnings("unchecked")
-    public static ConstructingObjectParser<LifecyclePolicy, String> PARSER = new ConstructingObjectParser<>("lifecycle_policy", false,
+    public static final ConstructingObjectParser<LifecyclePolicy, String> PARSER = new ConstructingObjectParser<>("lifecycle_policy", false,
             (a, name) -> {
                 List<Phase> phases = (List<Phase>) a[0];
                 Map<String, Phase> phaseMap = phases.stream().collect(Collectors.toMap(Phase::getName, Function.identity()));

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/action/CloseJobAction.java

@@ -40,7 +40,7 @@ public class CloseJobAction extends ActionType<CloseJobAction.Response> {
         public static final ParseField TIMEOUT = new ParseField("timeout");
         public static final ParseField FORCE = new ParseField("force");
         public static final ParseField ALLOW_NO_JOBS = new ParseField("allow_no_jobs");
-        public static ObjectParser<Request, Void> PARSER = new ObjectParser<>(NAME, Request::new);
+        public static final ObjectParser<Request, Void> PARSER = new ObjectParser<>(NAME, Request::new);
 
         static {
             PARSER.declareString(Request::setJobId, Job.ID);

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/action/IsolateDatafeedAction.java

@@ -46,8 +46,7 @@ public class IsolateDatafeedAction extends ActionType<IsolateDatafeedAction.Resp
 
     public static class Request extends BaseTasksRequest<Request> implements ToXContentObject {
 
-        public static ObjectParser<Request, Void> PARSER = new ObjectParser<>(NAME, Request::new);
-
+        public static final ObjectParser<Request, Void> PARSER = new ObjectParser<>(NAME, Request::new);
         static {
             PARSER.declareString((request, datafeedId) -> request.datafeedId = datafeedId, DatafeedConfig.ID);
         }

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/action/OpenJobAction.java

@@ -124,7 +124,7 @@ public class OpenJobAction extends ActionType<AcknowledgedResponse> {
         public static final ParseField TIMEOUT = new ParseField("timeout");
         public static final ParseField JOB = new ParseField("job");
 
-        public static ObjectParser<JobParams, Void> PARSER = new ObjectParser<>(MlTasks.JOB_TASK_NAME, true, JobParams::new);
+        public static final ObjectParser<JobParams, Void> PARSER = new ObjectParser<>(MlTasks.JOB_TASK_NAME, true, JobParams::new);
         static {
             PARSER.declareString(JobParams::setJobId, Job.ID);
             PARSER.declareString((params, val) ->

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/action/RevertModelSnapshotAction.java

@@ -42,8 +42,7 @@ public class RevertModelSnapshotAction extends ActionType<RevertModelSnapshotAct
         public static final ParseField SNAPSHOT_ID = new ParseField("snapshot_id");
         public static final ParseField DELETE_INTERVENING = new ParseField("delete_intervening_results");
 
-        private static ObjectParser<Request, Void> PARSER = new ObjectParser<>(NAME, Request::new);
-
+        private static final ObjectParser<Request, Void> PARSER = new ObjectParser<>(NAME, Request::new);
         static {
             PARSER.declareString((request, jobId) -> request.jobId = jobId, Job.ID);
             PARSER.declareString((request, snapshotId) -> request.snapshotId = snapshotId, SNAPSHOT_ID);

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/action/StartDataFrameAnalyticsAction.java

@@ -157,7 +157,7 @@ public class StartDataFrameAnalyticsAction extends ActionType<AcknowledgedRespon
         private static final ParseField PROGRESS_ON_START = new ParseField("progress_on_start");
 
         @SuppressWarnings("unchecked")
-        public static ConstructingObjectParser<TaskParams, Void> PARSER = new ConstructingObjectParser<>(
+        public static final ConstructingObjectParser<TaskParams, Void> PARSER = new ConstructingObjectParser<>(
             MlTasks.DATA_FRAME_ANALYTICS_TASK_NAME, true,
             a -> new TaskParams((String) a[0], (String) a[1], (List<PhaseProgress>) a[2], (Boolean) a[3]));
 

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/action/StartDatafeedAction.java

@@ -136,7 +136,11 @@ public class StartDatafeedAction extends ActionType<AcknowledgedResponse> {
 
         public static final ParseField INDICES = new ParseField("indices");
 
-        public static ObjectParser<DatafeedParams, Void> PARSER = new ObjectParser<>(MlTasks.DATAFEED_TASK_NAME, true, DatafeedParams::new);
+        public static final ObjectParser<DatafeedParams, Void> PARSER = new ObjectParser<>(
+            MlTasks.DATAFEED_TASK_NAME,
+            true,
+            DatafeedParams::new
+        );
         static {
             PARSER.declareString((params, datafeedId) -> params.datafeedId = datafeedId, DatafeedConfig.ID);
             PARSER.declareString((params, startTime) -> params.startTime = parseDateOrThrow(

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/action/StopDatafeedAction.java

@@ -44,8 +44,7 @@ public class StopDatafeedAction extends ActionType<StopDatafeedAction.Response>
         public static final ParseField FORCE = new ParseField("force");
         public static final ParseField ALLOW_NO_DATAFEEDS = new ParseField("allow_no_datafeeds");
 
-        public static ObjectParser<Request, Void> PARSER = new ObjectParser<>(NAME, Request::new);
-
+        public static final ObjectParser<Request, Void> PARSER = new ObjectParser<>(NAME, Request::new);
         static {
             PARSER.declareString((request, datafeedId) -> request.datafeedId = datafeedId, DatafeedConfig.ID);
             PARSER.declareString((request, val) ->

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/dataframe/explain/FieldSelection.java

@@ -46,7 +46,8 @@ public class FieldSelection implements ToXContentObject, Writeable {
         }
     }
 
-    public static ConstructingObjectParser<FieldSelection, Void> PARSER = new ConstructingObjectParser<>("field_selection",
+    @SuppressWarnings("unchecked")
+    public static final ConstructingObjectParser<FieldSelection, Void> PARSER = new ConstructingObjectParser<>("field_selection",
         a -> new FieldSelection((String) a[0], new HashSet<>((List<String>) a[1]), (boolean) a[2], (boolean) a[3], (FeatureType) a[4],
             (String) a[5]));
 

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/security/action/ApiKey.java

@@ -147,7 +147,7 @@ public final class ApiKey implements ToXContentObject, Writeable {
                 && Objects.equals(realm, other.realm);
     }
 
-    static ConstructingObjectParser<ApiKey, Void> PARSER = new ConstructingObjectParser<>("api_key", args -> {
+    static final ConstructingObjectParser<ApiKey, Void> PARSER = new ConstructingObjectParser<>("api_key", args -> {
         return new ApiKey((String) args[0], (String) args[1], Instant.ofEpochMilli((Long) args[2]),
                 (args[3] == null) ? null : Instant.ofEpochMilli((Long) args[3]), (Boolean) args[4], (String) args[5], (String) args[6]);
     });

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/security/action/CreateApiKeyResponse.java

@@ -31,7 +31,7 @@ import static org.elasticsearch.common.xcontent.ConstructingObjectParser.optiona
  */
 public final class CreateApiKeyResponse extends ActionResponse implements ToXContentObject {
 
-    static ConstructingObjectParser<CreateApiKeyResponse, Void> PARSER = new ConstructingObjectParser<>("create_api_key_response",
+    static final ConstructingObjectParser<CreateApiKeyResponse, Void> PARSER = new ConstructingObjectParser<>("create_api_key_response",
             args -> new CreateApiKeyResponse((String) args[0], (String) args[1], new SecureString((String) args[2]),
                     (args[3] == null) ? null : Instant.ofEpochMilli((Long) args[3])));
     static {

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/security/action/GetApiKeyResponse.java

@@ -63,7 +63,7 @@ public final class GetApiKeyResponse extends ActionResponse implements ToXConten
     }
 
     @SuppressWarnings("unchecked")
-    static ConstructingObjectParser<GetApiKeyResponse, Void> PARSER = new ConstructingObjectParser<>("get_api_key_response", args -> {
+    static final ConstructingObjectParser<GetApiKeyResponse, Void> PARSER = new ConstructingObjectParser<>("get_api_key_response", args -> {
         return (args[0] == null) ? GetApiKeyResponse.emptyResponse() : new GetApiKeyResponse((List<ApiKey>) args[0]);
     });
     static {

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/security/action/InvalidateApiKeyResponse.java

@@ -109,10 +109,13 @@ public final class InvalidateApiKeyResponse extends ActionResponse implements To
         out.writeCollection(errors, StreamOutput::writeException);
     }
 
-    static ConstructingObjectParser<InvalidateApiKeyResponse, Void> PARSER = new ConstructingObjectParser<>("invalidate_api_key_response",
-            args -> {
-                return new InvalidateApiKeyResponse((List<String>) args[0], (List<String>) args[1], (List<ElasticsearchException>) args[3]);
-            });
+    @SuppressWarnings("unchecked")
+    static final ConstructingObjectParser<InvalidateApiKeyResponse, Void> PARSER = new ConstructingObjectParser<>(
+        "invalidate_api_key_response",
+        args -> {
+            return new InvalidateApiKeyResponse((List<String>) args[0], (List<String>) args[1], (List<ElasticsearchException>) args[3]);
+        }
+    );
     static {
         PARSER.declareStringArray(constructorArg(), new ParseField("invalidated_api_keys"));
         PARSER.declareStringArray(constructorArg(), new ParseField("previously_invalidated_api_keys"));

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/transform/action/PreviewTransformAction.java

@@ -145,7 +145,7 @@ public class PreviewTransformAction extends ActionType<PreviewTransformAction.Re
         public static ParseField PREVIEW = new ParseField("preview");
         public static ParseField MAPPINGS = new ParseField("mappings");
 
-        static ObjectParser<Response, Void> PARSER = new ObjectParser<>("data_frame_transform_preview", Response::new);
+        static final ObjectParser<Response, Void> PARSER = new ObjectParser<>("data_frame_transform_preview", Response::new);
         static {
             PARSER.declareObjectArray(Response::setDocs, (p, c) -> p.mapOrdered(), PREVIEW);
             PARSER.declareObject(Response::setMappings, (p, c) -> p.mapOrdered(), MAPPINGS);