Minimize the usage of guava classes in interfaces, return types, arguments

Using these classes in interfaces forces downstream users to use shaded APIs.
We should minimize the usage of shaded APIs and keep them internal.

src/main/java/org/elasticsearch/action/admin/cluster/repositories/get/GetRepositoriesResponse.java

@@ -28,6 +28,7 @@ import org.elasticsearch.common.settings.Settings;
 
 import java.io.IOException;
 import java.util.Iterator;
+import java.util.List;
 
 /**
  * Get repositories response
@@ -49,7 +50,7 @@ public class GetRepositoriesResponse extends ActionResponse implements Iterable<
      *
      * @return list or repositories
      */
-    public ImmutableList<RepositoryMetaData> repositories() {
+    public List<RepositoryMetaData> repositories() {
         return repositories;
     }
 

src/main/java/org/elasticsearch/action/admin/cluster/snapshots/get/GetSnapshotsResponse.java

@@ -29,6 +29,7 @@ import org.elasticsearch.common.xcontent.XContentBuilderString;
 import org.elasticsearch.snapshots.SnapshotInfo;
 
 import java.io.IOException;
+import java.util.List;
 
 /**
  * Get snapshots response
@@ -49,7 +50,7 @@ public class GetSnapshotsResponse extends ActionResponse implements ToXContent {
      *
      * @return the list of snapshots
      */
-    public ImmutableList<SnapshotInfo> getSnapshots() {
+    public List<SnapshotInfo> getSnapshots() {
         return snapshots;
     }
 

src/main/java/org/elasticsearch/action/admin/cluster/snapshots/get/TransportGetSnapshotsAction.java

@@ -36,6 +36,8 @@ import org.elasticsearch.snapshots.SnapshotsService;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 
+import java.util.List;
+
 /**
  * Transport Action for get snapshots operation
  */
@@ -69,12 +71,12 @@ public class TransportGetSnapshotsAction extends TransportMasterNodeAction<GetSn
         try {
             ImmutableList.Builder<SnapshotInfo> snapshotInfoBuilder = ImmutableList.builder();
             if (isAllSnapshots(request.snapshots())) {
-                ImmutableList<Snapshot> snapshots = snapshotsService.snapshots(request.repository());
+                List<Snapshot> snapshots = snapshotsService.snapshots(request.repository());
                 for (Snapshot snapshot : snapshots) {
                     snapshotInfoBuilder.add(new SnapshotInfo(snapshot));
                 }
             } else if (isCurrentSnapshots(request.snapshots())) {
-                ImmutableList<Snapshot> snapshots = snapshotsService.currentSnapshots(request.repository());
+                List<Snapshot> snapshots = snapshotsService.currentSnapshots(request.repository());
                 for (Snapshot snapshot : snapshots) {
                     snapshotInfoBuilder.add(new SnapshotInfo(snapshot));
                 }

src/main/java/org/elasticsearch/action/admin/cluster/snapshots/status/TransportSnapshotsStatusAction.java

@@ -41,6 +41,7 @@ import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -81,7 +82,7 @@ public class TransportSnapshotsStatusAction extends TransportMasterNodeAction<Sn
     protected void masterOperation(final SnapshotsStatusRequest request,
                                    final ClusterState state,
                                    final ActionListener<SnapshotsStatusResponse> listener) throws Exception {
-        ImmutableList<SnapshotMetaData.Entry> currentSnapshots = snapshotsService.currentSnapshots(request.repository(), request.snapshots());
+        List<SnapshotMetaData.Entry> currentSnapshots = snapshotsService.currentSnapshots(request.repository(), request.snapshots());
 
         if (currentSnapshots.isEmpty()) {
             listener.onResponse(buildResponse(request, currentSnapshots, null));
@@ -110,7 +111,7 @@ public class TransportSnapshotsStatusAction extends TransportMasterNodeAction<Sn
                         @Override
                         public void onResponse(TransportNodesSnapshotsStatus.NodesSnapshotStatus nodeSnapshotStatuses) {
                             try {
-                                ImmutableList<SnapshotMetaData.Entry> currentSnapshots =
+                                List<SnapshotMetaData.Entry> currentSnapshots =
                                         snapshotsService.currentSnapshots(request.repository(), request.snapshots());
                                 listener.onResponse(buildResponse(request, currentSnapshots, nodeSnapshotStatuses));
                             } catch (Throwable e) {
@@ -130,7 +131,7 @@ public class TransportSnapshotsStatusAction extends TransportMasterNodeAction<Sn
 
     }
 
-    private SnapshotsStatusResponse buildResponse(SnapshotsStatusRequest request, ImmutableList<SnapshotMetaData.Entry> currentSnapshots,
+    private SnapshotsStatusResponse buildResponse(SnapshotsStatusRequest request, List<SnapshotMetaData.Entry> currentSnapshots,
                                                   TransportNodesSnapshotsStatus.NodesSnapshotStatus nodeSnapshotStatuses) throws IOException {
         // First process snapshot that are currently processed
         ImmutableList.Builder<SnapshotStatus> builder = ImmutableList.builder();

src/main/java/org/elasticsearch/client/transport/TransportClient.java

@@ -19,8 +19,6 @@
 
 package org.elasticsearch.client.transport;
 
-import com.google.common.collect.ImmutableList;
-
 import org.elasticsearch.Version;
 import org.elasticsearch.action.Action;
 import org.elasticsearch.action.ActionListener;
@@ -56,6 +54,7 @@ import org.elasticsearch.transport.TransportModule;
 import org.elasticsearch.transport.TransportService;
 import org.elasticsearch.transport.netty.NettyTransport;
 
+import java.util.List;
 import java.util.concurrent.TimeUnit;
 
 import static org.elasticsearch.common.settings.Settings.settingsBuilder;
@@ -180,7 +179,7 @@ public class TransportClient extends AbstractClient {
      * Returns the current registered transport addresses to use (added using
      * {@link #addTransportAddress(org.elasticsearch.common.transport.TransportAddress)}.
      */
-    public ImmutableList<TransportAddress> transportAddresses() {
+    public List<TransportAddress> transportAddresses() {
         return nodesService.transportAddresses();
     }
 
@@ -190,7 +189,7 @@ public class TransportClient extends AbstractClient {
      * <p>The nodes include all the nodes that are currently alive based on the transport
      * addresses provided.
      */
-    public ImmutableList<DiscoveryNode> connectedNodes() {
+    public List<DiscoveryNode> connectedNodes() {
         return nodesService.connectedNodes();
     }
 
@@ -198,14 +197,14 @@ public class TransportClient extends AbstractClient {
      * The list of filtered nodes that were not connected to, for example, due to
      * mismatch in cluster name.
      */
-    public ImmutableList<DiscoveryNode> filteredNodes() {
+    public List<DiscoveryNode> filteredNodes() {
         return nodesService.filteredNodes();
     }
 
     /**
      * Returns the listed nodes in the transport client (ones added to it).
      */
-    public ImmutableList<DiscoveryNode> listedNodes() {
+    public List<DiscoveryNode> listedNodes() {
         return nodesService.listedNodes();
     }
 

src/main/java/org/elasticsearch/client/transport/TransportClientNodesService.java

@@ -77,8 +77,8 @@ public class TransportClientNodesService extends AbstractComponent {
 
     private final Object mutex = new Object();
 
-    private volatile ImmutableList<DiscoveryNode> nodes = ImmutableList.of();
+    private volatile List<DiscoveryNode> nodes = ImmutableList.of();
-    private volatile ImmutableList<DiscoveryNode> filteredNodes = ImmutableList.of();
+    private volatile List<DiscoveryNode> filteredNodes = ImmutableList.of();
 
     private final AtomicInteger tempNodeIdGenerator = new AtomicInteger();
 
@@ -118,7 +118,7 @@ public class TransportClientNodesService extends AbstractComponent {
         this.nodesSamplerFuture = threadPool.schedule(nodesSamplerInterval, ThreadPool.Names.GENERIC, new ScheduledNodeSampler());
     }
 
-    public ImmutableList<TransportAddress> transportAddresses() {
+    public List<TransportAddress> transportAddresses() {
         ImmutableList.Builder<TransportAddress> lstBuilder = ImmutableList.builder();
         for (DiscoveryNode listedNode : listedNodes) {
             lstBuilder.add(listedNode.address());
@@ -126,15 +126,15 @@ public class TransportClientNodesService extends AbstractComponent {
         return lstBuilder.build();
     }
 
-    public ImmutableList<DiscoveryNode> connectedNodes() {
+    public List<DiscoveryNode> connectedNodes() {
         return this.nodes;
     }
 
-    public ImmutableList<DiscoveryNode> filteredNodes() {
+    public List<DiscoveryNode> filteredNodes() {
         return this.filteredNodes;
     }
 
-    public ImmutableList<DiscoveryNode> listedNodes() {
+    public List<DiscoveryNode> listedNodes() {
         return this.listedNodes;
     }
 
@@ -193,7 +193,7 @@ public class TransportClientNodesService extends AbstractComponent {
     }
 
     public <Response> void execute(NodeListenerCallback<Response> callback, ActionListener<Response> listener) {
-        ImmutableList<DiscoveryNode> nodes = this.nodes;
+        List<DiscoveryNode> nodes = this.nodes;
         ensureNodesAreAvailable(nodes);
         int index = getNodeNumber();
         RetryListener<Response> retryListener = new RetryListener<>(callback, listener, nodes, index);
@@ -209,12 +209,12 @@ public class TransportClientNodesService extends AbstractComponent {
     public static class RetryListener<Response> implements ActionListener<Response> {
         private final NodeListenerCallback<Response> callback;
         private final ActionListener<Response> listener;
-        private final ImmutableList<DiscoveryNode> nodes;
+        private final List<DiscoveryNode> nodes;
         private final int index;
 
         private volatile int i;
 
-        public RetryListener(NodeListenerCallback<Response> callback, ActionListener<Response> listener, ImmutableList<DiscoveryNode> nodes, int index) {
+        public RetryListener(NodeListenerCallback<Response> callback, ActionListener<Response> listener, List<DiscoveryNode> nodes, int index) {
             this.callback = callback;
             this.listener = listener;
             this.nodes = nodes;
@@ -274,7 +274,7 @@ public class TransportClientNodesService extends AbstractComponent {
         return index;
     }
 
-    private void ensureNodesAreAvailable(ImmutableList<DiscoveryNode> nodes) {
+    private void ensureNodesAreAvailable(List<DiscoveryNode> nodes) {
         if (nodes.isEmpty()) {
             String message = String.format(Locale.ROOT, "None of the configured nodes are available: %s", nodes);
             throw new NoNodeAvailableException(message);
@@ -297,7 +297,7 @@ public class TransportClientNodesService extends AbstractComponent {
          * validates a set of potentially newly discovered nodes and returns an immutable
          * list of the nodes that has passed.
          */
-        protected ImmutableList<DiscoveryNode> validateNewNodes(Set<DiscoveryNode> nodes) {
+        protected List<DiscoveryNode> validateNewNodes(Set<DiscoveryNode> nodes) {
             for (Iterator<DiscoveryNode> it = nodes.iterator(); it.hasNext(); ) {
                 DiscoveryNode node = it.next();
                 if (!transportService.nodeConnected(node)) {

src/main/java/org/elasticsearch/cluster/metadata/RestoreMetaData.java

@@ -31,6 +31,7 @@ import org.elasticsearch.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.EnumSet;
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -67,7 +68,7 @@ public class RestoreMetaData extends AbstractDiffable<MetaData.Custom> implement
      *
      * @return list of currently running restore processes
      */
-    public ImmutableList<Entry> entries() {
+    public List<Entry> entries() {
         return this.entries;
     }
 

src/main/java/org/elasticsearch/cluster/metadata/SnapshotMetaData.java

@@ -33,6 +33,7 @@ import org.elasticsearch.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.EnumSet;
+import java.util.List;
 import java.util.Map;
 
 import static com.google.common.collect.Maps.newHashMap;
@@ -319,7 +320,7 @@ public class SnapshotMetaData extends AbstractDiffable<Custom> implements MetaDa
         this.entries = ImmutableList.copyOf(entries);
     }
 
-    public ImmutableList<Entry> entries() {
+    public List<Entry> entries() {
         return this.entries;
     }
 

src/main/java/org/elasticsearch/cluster/node/DiscoveryNodes.java

@@ -508,7 +508,7 @@ public class DiscoveryNodes extends AbstractDiffable<DiscoveryNodes> implements
             return !removed.isEmpty();
         }
 
-        public ImmutableList<DiscoveryNode> removedNodes() {
+        public List<DiscoveryNode> removedNodes() {
             return removed;
         }
 
@@ -516,7 +516,7 @@ public class DiscoveryNodes extends AbstractDiffable<DiscoveryNodes> implements
             return !added.isEmpty();
         }
 
-        public ImmutableList<DiscoveryNode> addedNodes() {
+        public List<DiscoveryNode> addedNodes() {
             return added;
         }
 

src/main/java/org/elasticsearch/cluster/routing/IndexShardRoutingTable.java

@@ -63,10 +63,10 @@ public class IndexShardRoutingTable implements Iterable<ShardRouting> {
 
     final boolean primaryAllocatedPostApi;
 
-    IndexShardRoutingTable(ShardId shardId, ImmutableList<ShardRouting> shards, boolean primaryAllocatedPostApi) {
+    IndexShardRoutingTable(ShardId shardId, List<ShardRouting> shards, boolean primaryAllocatedPostApi) {
         this.shardId = shardId;
         this.shuffler = new RotationShardShuffler(ThreadLocalRandom.current().nextInt());
-        this.shards = shards;
+        this.shards = ImmutableList.copyOf(shards);
         this.primaryAllocatedPostApi = primaryAllocatedPostApi;
 
         ShardRouting primary = null;
@@ -173,7 +173,7 @@ public class IndexShardRoutingTable implements Iterable<ShardRouting> {
     }
 
     @Override
-    public UnmodifiableIterator<ShardRouting> iterator() {
+    public Iterator<ShardRouting> iterator() {
         return shards.iterator();
     }
 
@@ -192,56 +192,56 @@ public class IndexShardRoutingTable implements Iterable<ShardRouting> {
     }
 
     /**
-     * Returns a {@link ImmutableList} of shards
+     * Returns a {@link List} of shards
      *
-     * @return a {@link ImmutableList} of shards
+     * @return a {@link List} of shards
      */
-    public ImmutableList<ShardRouting> shards() {
+    public List<ShardRouting> shards() {
         return this.shards;
     }
 
     /**
-     * Returns a {@link ImmutableList} of shards
+     * Returns a {@link List} of shards
      *
-     * @return a {@link ImmutableList} of shards
+     * @return a {@link List} of shards
      */
-    public ImmutableList<ShardRouting> getShards() {
+    public List<ShardRouting> getShards() {
         return shards();
     }
 
     /**
-     * Returns a {@link ImmutableList} of active shards
+     * Returns a {@link List} of active shards
      *
-     * @return a {@link ImmutableList} of shards
+     * @return a {@link List} of shards
      */
-    public ImmutableList<ShardRouting> activeShards() {
+    public List<ShardRouting> activeShards() {
         return this.activeShards;
     }
 
     /**
-     * Returns a {@link ImmutableList} of active shards
+     * Returns a {@link List} of active shards
      *
-     * @return a {@link ImmutableList} of shards
+     * @return a {@link List} of shards
      */
-    public ImmutableList<ShardRouting> getActiveShards() {
+    public List<ShardRouting> getActiveShards() {
         return activeShards();
     }
 
     /**
-     * Returns a {@link ImmutableList} of assigned shards
+     * Returns a {@link List} of assigned shards
      *
-     * @return a {@link ImmutableList} of shards
+     * @return a {@link List} of shards
      */
-    public ImmutableList<ShardRouting> assignedShards() {
+    public List<ShardRouting> assignedShards() {
         return this.assignedShards;
     }
 
     /**
-     * Returns a {@link ImmutableList} of assigned shards
+     * Returns a {@link List} of assigned shards
      *
-     * @return a {@link ImmutableList} of shards
+     * @return a {@link List} of shards
      */
-    public ImmutableList<ShardRouting> getAssignedShards() {
+    public List<ShardRouting> getAssignedShards() {
         return this.assignedShards;
     }
 

src/main/java/org/elasticsearch/common/blobstore/BlobContainer.java

@@ -24,6 +24,7 @@ import com.google.common.collect.ImmutableMap;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.util.Map;
 
 /**
  *
@@ -59,12 +60,12 @@ public interface BlobContainer {
     /**
      * Lists all blobs in the container
      */
-    ImmutableMap<String, BlobMetaData> listBlobs() throws IOException;
+    Map<String, BlobMetaData> listBlobs() throws IOException;
 
     /**
      * Lists all blobs in the container that match specified prefix
      */
-    ImmutableMap<String, BlobMetaData> listBlobsByPrefix(String blobNamePrefix) throws IOException;
+    Map<String, BlobMetaData> listBlobsByPrefix(String blobNamePrefix) throws IOException;
 
     /**
      * Atomically renames source blob into target blob

src/main/java/org/elasticsearch/common/blobstore/support/AbstractBlobContainer.java

@@ -25,6 +25,7 @@ import org.elasticsearch.common.blobstore.BlobMetaData;
 import org.elasticsearch.common.blobstore.BlobPath;
 
 import java.io.IOException;
+import java.util.Map;
 
 /**
  *
@@ -44,7 +45,7 @@ public abstract class AbstractBlobContainer implements BlobContainer {
 
     @Override
     public void deleteBlobsByPrefix(final String blobNamePrefix) throws IOException {
-        ImmutableMap<String, BlobMetaData> blobs = listBlobsByPrefix(blobNamePrefix);
+        Map<String, BlobMetaData> blobs = listBlobsByPrefix(blobNamePrefix);
         for (BlobMetaData blob : blobs.values()) {
             deleteBlob(blob.name());
         }

src/main/java/org/elasticsearch/common/util/CollectionUtils.java

@@ -24,13 +24,17 @@ import com.carrotsearch.hppc.FloatArrayList;
 import com.carrotsearch.hppc.LongArrayList;
 import com.carrotsearch.hppc.ObjectArrayList;
 import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterators;
+import com.google.common.collect.Lists;
 import org.apache.lucene.util.*;
+import org.elasticsearch.common.inject.Module;
 
 import java.util.*;
 
 /** Collections-related utility methods. */
 public enum CollectionUtils {
-    ;
+    CollectionUtils;
 
     public static void sort(LongArrayList list) {
         sort(list.buffer, list.size());
@@ -357,5 +361,15 @@ public enum CollectionUtils {
 
     }
 
+    /**
+     * Combines multiple iterators into a single iterator.
+     */
+    public static <T> Iterator<T> concat(Iterator<? extends T>... iterators) {
+        return Iterators.concat(iterators);
+    }
+
+    public static <E> ArrayList<E> newArrayList(E... elements) {
+        return Lists.newArrayList(elements);
+    }
 
 }

src/main/java/org/elasticsearch/index/analysis/Analysis.java

@@ -152,7 +152,7 @@ public class Analysis {
             .put("_turkish_", TurkishAnalyzer.getDefaultStopSet())
             .immutableMap();
 
-    public static CharArraySet parseWords(Environment env, Settings settings, String name, CharArraySet defaultWords, ImmutableMap<String, Set<?>> namedWords, boolean ignoreCase) {
+    public static CharArraySet parseWords(Environment env, Settings settings, String name, CharArraySet defaultWords, Map<String, Set<?>> namedWords, boolean ignoreCase) {
         String value = settings.get(name);
         if (value != null) {
             if ("_none_".equals(value)) {
@@ -184,7 +184,7 @@ public class Analysis {
         return parseWords(env, settings, "stopwords", defaultStopWords, namedStopWords, ignoreCase);
     }
 
-    private static CharArraySet resolveNamedWords(Collection<String> words, ImmutableMap<String, Set<?>> namedWords, boolean ignoreCase) {
+    private static CharArraySet resolveNamedWords(Collection<String> words, Map<String, Set<?>> namedWords, boolean ignoreCase) {
         if (namedWords == null) {
             return new CharArraySet(words, ignoreCase);
         }

src/main/java/org/elasticsearch/index/gateway/CommitPoint.java

@@ -105,11 +105,11 @@ public class CommitPoint {
         return this.type;
     }
 
-    public ImmutableList<FileInfo> indexFiles() {
+    public List<FileInfo> indexFiles() {
         return this.indexFiles;
     }
 
-    public ImmutableList<FileInfo> translogFiles() {
+    public List<FileInfo> translogFiles() {
         return this.translogFiles;
     }
 

src/main/java/org/elasticsearch/index/gateway/CommitPoints.java

@@ -49,7 +49,7 @@ public class CommitPoints implements Iterable<CommitPoint> {
         this.commitPoints = ImmutableList.copyOf(commitPoints);
     }
 
-    public ImmutableList<CommitPoint> commits() {
+    public List<CommitPoint> commits() {
         return this.commitPoints;
     }
 

src/main/java/org/elasticsearch/index/mapper/DocumentParser.java

@@ -43,6 +43,7 @@ import org.elasticsearch.index.mapper.object.RootObjectMapper;
 import java.io.Closeable;
 import java.io.IOException;
 import java.util.Collections;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -598,7 +599,7 @@ class DocumentParser implements Closeable {
     }
 
     /** Creates instances of the fields that the current field should be copied to */
-    private static void parseCopyFields(ParseContext context, FieldMapper fieldMapper, ImmutableList<String> copyToFields) throws IOException {
+    private static void parseCopyFields(ParseContext context, FieldMapper fieldMapper, List<String> copyToFields) throws IOException {
         if (!context.isWithinCopyTo() && copyToFields.isEmpty() == false) {
             context = context.createCopyToContext();
             for (String field : copyToFields) {

src/main/java/org/elasticsearch/index/mapper/core/AbstractFieldMapper.java

@@ -891,7 +891,7 @@ public abstract class AbstractFieldMapper implements FieldMapper {
             }
         }
 
-        public ImmutableList<String> copyToFields() {
+        public List<String> copyToFields() {
             return copyToFields;
         }
     }

src/main/java/org/elasticsearch/index/snapshots/blobstore/BlobStoreIndexShardRepository.java

@@ -318,7 +318,7 @@ public class BlobStoreIndexShardRepository extends AbstractComponent implements
          * Delete shard snapshot
          */
         public void delete() {
-            final ImmutableMap<String, BlobMetaData> blobs;
+            final Map<String, BlobMetaData> blobs;
             try {
                 blobs = blobContainer.listBlobs();
             } catch (IOException e) {
@@ -372,7 +372,7 @@ public class BlobStoreIndexShardRepository extends AbstractComponent implements
          * @param fileListGeneration the generation number of the snapshot index file
          * @param blobs     list of blobs in the container
          */
-        protected void finalize(List<SnapshotFiles> snapshots, int fileListGeneration, ImmutableMap<String, BlobMetaData> blobs) {
+        protected void finalize(List<SnapshotFiles> snapshots, int fileListGeneration, Map<String, BlobMetaData> blobs) {
             BlobStoreIndexShardSnapshots newSnapshots = new BlobStoreIndexShardSnapshots(snapshots);
             // delete old index files first
             for (String blobName : blobs.keySet()) {
@@ -437,7 +437,7 @@ public class BlobStoreIndexShardRepository extends AbstractComponent implements
          * @param blobs list of blobs in the repository
          * @return next available blob number
          */
-        protected long findLatestFileNameGeneration(ImmutableMap<String, BlobMetaData> blobs) {
+        protected long findLatestFileNameGeneration(Map<String, BlobMetaData> blobs) {
             long generation = -1;
             for (String name : blobs.keySet()) {
                 if (!name.startsWith(DATA_BLOB_PREFIX)) {
@@ -462,7 +462,7 @@ public class BlobStoreIndexShardRepository extends AbstractComponent implements
          * @param blobs list of blobs in repository
          * @return tuple of BlobStoreIndexShardSnapshots and the last snapshot index generation
          */
-        protected Tuple<BlobStoreIndexShardSnapshots, Integer> buildBlobStoreIndexShardSnapshots(ImmutableMap<String, BlobMetaData> blobs) {
+        protected Tuple<BlobStoreIndexShardSnapshots, Integer> buildBlobStoreIndexShardSnapshots(Map<String, BlobMetaData> blobs) {
             int latest = -1;
             for (String name : blobs.keySet()) {
                 if (name.startsWith(SNAPSHOT_INDEX_PREFIX)) {
@@ -538,7 +538,7 @@ public class BlobStoreIndexShardRepository extends AbstractComponent implements
             logger.debug("[{}] [{}] snapshot to [{}] ...", shardId, snapshotId, repositoryName);
             store.incRef();
             try {
-                final ImmutableMap<String, BlobMetaData> blobs;
+                final Map<String, BlobMetaData> blobs;
                 try {
                     blobs = blobContainer.listBlobs();
                 } catch (IOException e) {
@@ -570,7 +570,7 @@ public class BlobStoreIndexShardRepository extends AbstractComponent implements
                     logger.trace("[{}] [{}] Processing [{}]", shardId, snapshotId, fileName);
                     final StoreFileMetaData md = metadata.get(fileName);
                     FileInfo existingFileInfo = null;
-                    ImmutableList<FileInfo> filesInfo = snapshots.findPhysicalIndexFiles(fileName);
+                    List<FileInfo> filesInfo = snapshots.findPhysicalIndexFiles(fileName);
                     if (filesInfo != null) {
                         for (FileInfo fileInfo : filesInfo) {
                             try {
@@ -696,7 +696,7 @@ public class BlobStoreIndexShardRepository extends AbstractComponent implements
          * @param blobs    list of blobs
          * @return true if file exists in the list of blobs
          */
-        private boolean snapshotFileExistsInBlobs(BlobStoreIndexShardSnapshot.FileInfo fileInfo, ImmutableMap<String, BlobMetaData> blobs) {
+        private boolean snapshotFileExistsInBlobs(BlobStoreIndexShardSnapshot.FileInfo fileInfo, Map<String, BlobMetaData> blobs) {
             BlobMetaData blobMetaData = blobs.get(fileInfo.name());
             if (blobMetaData != null) {
                 return blobMetaData.length() == fileInfo.length();

src/main/java/org/elasticsearch/index/snapshots/blobstore/BlobStoreIndexShardSnapshot.java

@@ -364,7 +364,7 @@ public class BlobStoreIndexShardSnapshot {
      *
      * @return list of files
      */
-    public ImmutableList<FileInfo> indexFiles() {
+    public List<FileInfo> indexFiles() {
         return indexFiles;
     }
 

src/main/java/org/elasticsearch/index/snapshots/blobstore/BlobStoreIndexShardSnapshots.java

@@ -108,7 +108,7 @@ public class BlobStoreIndexShardSnapshots implements Iterable<SnapshotFiles>, To
      *
      * @return list of snapshots
      */
-    public ImmutableList<SnapshotFiles> snapshots() {
+    public List<SnapshotFiles> snapshots() {
         return this.shardSnapshots;
     }
 
@@ -118,7 +118,7 @@ public class BlobStoreIndexShardSnapshots implements Iterable<SnapshotFiles>, To
      * @param physicalName original name
      * @return a list of file infos that match specified physical file or null if the file is not present in any of snapshots
      */
-    public ImmutableList<FileInfo> findPhysicalIndexFiles(String physicalName) {
+    public List<FileInfo> findPhysicalIndexFiles(String physicalName) {
         return physicalFiles.get(physicalName);
     }
 

src/main/java/org/elasticsearch/index/snapshots/blobstore/SnapshotFiles.java

@@ -21,6 +21,7 @@ package org.elasticsearch.index.snapshots.blobstore;
 import com.google.common.collect.ImmutableList;
 import org.elasticsearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshot.FileInfo;
 
+import java.util.List;
 import java.util.Map;
 
 import static com.google.common.collect.Maps.newHashMap;
@@ -32,7 +33,7 @@ public class SnapshotFiles {
 
     private final String snapshot;
 
-    private final ImmutableList<FileInfo> indexFiles;
+    private final List<FileInfo> indexFiles;
 
     private Map<String, FileInfo> physicalFiles = null;
 
@@ -40,7 +41,7 @@ public class SnapshotFiles {
         return snapshot;
     }
 
-    public SnapshotFiles(String snapshot, ImmutableList<FileInfo> indexFiles ) {
+    public SnapshotFiles(String snapshot, List<FileInfo> indexFiles ) {
         this.snapshot = snapshot;
         this.indexFiles = indexFiles;
     }
@@ -48,7 +49,7 @@ public class SnapshotFiles {
     /**
      * Returns a list of file in the snapshot
      */
-    public ImmutableList<FileInfo> indexFiles() {
+    public List<FileInfo> indexFiles() {
         return indexFiles;
     }
 

src/main/java/org/elasticsearch/plugins/PluginsService.java

@@ -415,7 +415,7 @@ public class PluginsService extends AbstractComponent {
         }
     }
 
-    private ImmutableList<Tuple<PluginInfo,Plugin>> loadPluginsFromClasspath(Settings settings) {
+    private List<Tuple<PluginInfo,Plugin>> loadPluginsFromClasspath(Settings settings) {
         ImmutableList.Builder<Tuple<PluginInfo, Plugin>> plugins = ImmutableList.builder();
 
         // Trying JVM plugins: looking for es-plugin.properties files

src/main/java/org/elasticsearch/repositories/Repository.java

@@ -26,6 +26,7 @@ import org.elasticsearch.snapshots.Snapshot;
 import org.elasticsearch.snapshots.SnapshotShardFailure;
 
 import java.io.IOException;
+import java.util.List;
 
 /**
  * Snapshot repository interface.
@@ -36,7 +37,7 @@ import java.io.IOException;
  * <p/>
  * Typical snapshot usage pattern:
  * <ul>
- * <li>Master calls {@link #initializeSnapshot(org.elasticsearch.cluster.metadata.SnapshotId, com.google.common.collect.ImmutableList, org.elasticsearch.cluster.metadata.MetaData)}
+ * <li>Master calls {@link #initializeSnapshot(org.elasticsearch.cluster.metadata.SnapshotId, List, org.elasticsearch.cluster.metadata.MetaData)}
  * with list of indices that will be included into the snapshot</li>
  * <li>Data nodes call {@link org.elasticsearch.index.snapshots.IndexShardRepository#snapshot(org.elasticsearch.cluster.metadata.SnapshotId, org.elasticsearch.index.shard.ShardId, org.elasticsearch.index.deletionpolicy.SnapshotIndexCommit, org.elasticsearch.index.snapshots.IndexShardSnapshotStatus)} for each shard</li>
  * <li>When all shard calls return master calls {@link #finalizeSnapshot}
@@ -62,14 +63,14 @@ public interface Repository extends LifecycleComponent<Repository> {
      * @param indices    list of indices
      * @return information about snapshot
      */
-    MetaData readSnapshotMetaData(SnapshotId snapshotId, ImmutableList<String> indices) throws IOException;
+    MetaData readSnapshotMetaData(SnapshotId snapshotId, List<String> indices) throws IOException;
 
     /**
      * Returns the list of snapshots currently stored in the repository
      *
      * @return snapshot list
      */
-    ImmutableList<SnapshotId> snapshots();
+    List<SnapshotId> snapshots();
 
     /**
      * Starts snapshotting process
@@ -78,7 +79,7 @@ public interface Repository extends LifecycleComponent<Repository> {
      * @param indices    list of indices to be snapshotted
      * @param metaData   cluster metadata
      */
-    void initializeSnapshot(SnapshotId snapshotId, ImmutableList<String> indices, MetaData metaData);
+    void initializeSnapshot(SnapshotId snapshotId, List<String> indices, MetaData metaData);
 
     /**
      * Finalizes snapshotting process
@@ -91,7 +92,7 @@ public interface Repository extends LifecycleComponent<Repository> {
      * @param shardFailures list of shard failures
      * @return snapshot description
      */
-    Snapshot finalizeSnapshot(SnapshotId snapshotId, ImmutableList<String> indices, long startTime, String failure, int totalShards, ImmutableList<SnapshotShardFailure> shardFailures);
+    Snapshot finalizeSnapshot(SnapshotId snapshotId, List<String> indices, long startTime, String failure, int totalShards, List<SnapshotShardFailure> shardFailures);
 
     /**
      * Deletes snapshot

src/main/java/org/elasticsearch/repositories/blobstore/BlobStoreRepository.java

@@ -75,6 +75,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.file.NoSuchFileException;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
@@ -235,7 +236,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent<Rep
      * {@inheritDoc}
      */
     @Override
-    public void initializeSnapshot(SnapshotId snapshotId, ImmutableList<String> indices, MetaData metaData) {
+    public void initializeSnapshot(SnapshotId snapshotId, List<String> indices, MetaData metaData) {
         try {
             String snapshotBlobName = snapshotBlobName(snapshotId);
             if (snapshotsBlobContainer.blobExists(snapshotBlobName)) {
@@ -268,7 +269,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent<Rep
      */
     @Override
     public void deleteSnapshot(SnapshotId snapshotId) {
-        ImmutableList<String> indices = ImmutableList.of();
+        List<String> indices = Collections.EMPTY_LIST;
         try {
             indices = readSnapshot(snapshotId).indices();
         } catch (SnapshotMissingException ex) {
@@ -288,7 +289,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent<Rep
             snapshotsBlobContainer.deleteBlob(blobName);
             snapshotsBlobContainer.deleteBlob(metaDataBlobName(snapshotId));
             // Delete snapshot from the snapshot list
-            ImmutableList<SnapshotId> snapshotIds = snapshots();
+            List<SnapshotId> snapshotIds = snapshots();
             if (snapshotIds.contains(snapshotId)) {
                 ImmutableList.Builder<SnapshotId> builder = ImmutableList.builder();
                 for (SnapshotId id : snapshotIds) {
@@ -352,7 +353,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent<Rep
      * {@inheritDoc}
      */
     @Override
-    public Snapshot finalizeSnapshot(SnapshotId snapshotId, ImmutableList<String> indices, long startTime, String failure, int totalShards, ImmutableList<SnapshotShardFailure> shardFailures) {
+    public Snapshot finalizeSnapshot(SnapshotId snapshotId, List<String> indices, long startTime, String failure, int totalShards, List<SnapshotShardFailure> shardFailures) {
         try {
             String tempBlobName = tempSnapshotBlobName(snapshotId);
             String blobName = snapshotBlobName(snapshotId);
@@ -361,7 +362,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent<Rep
                 writeSnapshot(blobStoreSnapshot, output);
             }
             snapshotsBlobContainer.move(tempBlobName, blobName);
-            ImmutableList<SnapshotId> snapshotIds = snapshots();
+            List<SnapshotId> snapshotIds = snapshots();
             if (!snapshotIds.contains(snapshotId)) {
                 snapshotIds = ImmutableList.<SnapshotId>builder().addAll(snapshotIds).add(snapshotId).build();
             }
@@ -376,10 +377,10 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent<Rep
      * {@inheritDoc}
      */
     @Override
-    public ImmutableList<SnapshotId> snapshots() {
+    public List<SnapshotId> snapshots() {
         try {
             List<SnapshotId> snapshots = newArrayList();
-            ImmutableMap<String, BlobMetaData> blobs;
+            Map<String, BlobMetaData> blobs;
             try {
                 blobs = snapshotsBlobContainer.listBlobsByPrefix(SNAPSHOT_PREFIX);
             } catch (UnsupportedOperationException ex) {
@@ -401,7 +402,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent<Rep
      * {@inheritDoc}
      */
     @Override
-    public MetaData readSnapshotMetaData(SnapshotId snapshotId, ImmutableList<String> indices) throws IOException {
+    public MetaData readSnapshotMetaData(SnapshotId snapshotId, List<String> indices) throws IOException {
         return readSnapshotMetaData(snapshotId, indices, false);
     }
 
@@ -421,7 +422,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent<Rep
         }
     }
 
-    private MetaData readSnapshotMetaData(SnapshotId snapshotId, ImmutableList<String> indices, boolean ignoreIndexErrors) throws IOException {
+    private MetaData readSnapshotMetaData(SnapshotId snapshotId, List<String> indices, boolean ignoreIndexErrors) throws IOException {
         MetaData metaData;
         try (InputStream blob = snapshotsBlobContainer.openInput(metaDataBlobName(snapshotId))) {
             byte[] data = ByteStreams.toByteArray(blob);
@@ -597,7 +598,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent<Rep
      * @param snapshots list of snapshot ids
      * @throws IOException I/O errors
      */
-    protected void writeSnapshotList(ImmutableList<SnapshotId> snapshots) throws IOException {
+    protected void writeSnapshotList(List<SnapshotId> snapshots) throws IOException {
         BytesStreamOutput bStream = new BytesStreamOutput();
         StreamOutput stream = compressIfNeeded(bStream);
         XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON, stream);
@@ -623,7 +624,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent<Rep
      * @return list of snapshots in the repository
      * @throws IOException I/O errors
      */
-    protected ImmutableList<SnapshotId> readSnapshotList() throws IOException {
+    protected List<SnapshotId> readSnapshotList() throws IOException {
         try (InputStream blob = snapshotsBlobContainer.openInput(SNAPSHOTS_FILE)) {
             final byte[] data = ByteStreams.toByteArray(blob);
             ArrayList<SnapshotId> snapshots = new ArrayList<>();

src/main/java/org/elasticsearch/repositories/uri/URLRepository.java

@@ -33,6 +33,7 @@ import org.elasticsearch.repositories.blobstore.BlobStoreRepository;
 
 import java.io.IOException;
 import java.net.URL;
+import java.util.List;
 
 /**
  * Read-only URL-based implementation of the BlobStoreRepository
@@ -90,7 +91,7 @@ public class URLRepository extends BlobStoreRepository {
     }
 
     @Override
-    public ImmutableList<SnapshotId> snapshots() {
+    public List<SnapshotId> snapshots() {
         if (listDirectories) {
             return super.snapshots();
         } else {

src/main/java/org/elasticsearch/snapshots/RestoreInfo.java

@@ -28,6 +28,7 @@ import org.elasticsearch.common.xcontent.XContentBuilderString;
 import org.elasticsearch.rest.RestStatus;
 
 import java.io.IOException;
+import java.util.List;
 
 /**
  * Information about successfully completed restore operation.
@@ -69,7 +70,7 @@ public class RestoreInfo implements ToXContent, Streamable {
      *
      * @return list of restored indices
      */
-    public ImmutableList<String> indices() {
+    public List<String> indices() {
         return indices;
     }
 

src/main/java/org/elasticsearch/snapshots/RestoreService.java

@@ -156,7 +156,7 @@ public class RestoreService extends AbstractComponent implements ClusterStateLis
             Repository repository = repositoriesService.repository(request.repository());
             final SnapshotId snapshotId = new SnapshotId(request.repository(), request.name());
             final Snapshot snapshot = repository.readSnapshot(snapshotId);
-            ImmutableList<String> filteredIndices = SnapshotUtils.filterIndices(snapshot.indices(), request.indices(), request.indicesOptions());
+            List<String> filteredIndices = SnapshotUtils.filterIndices(snapshot.indices(), request.indices(), request.indicesOptions());
             MetaData metaDataIn = repository.readSnapshotMetaData(snapshotId, filteredIndices);
 
             final MetaData metaData;
@@ -658,7 +658,7 @@ public class RestoreService extends AbstractComponent implements ClusterStateLis
         return failedShards;
     }
 
-    private Map<String, String> renamedIndices(RestoreRequest request, ImmutableList<String> filteredIndices) {
+    private Map<String, String> renamedIndices(RestoreRequest request, List<String> filteredIndices) {
         Map<String, String> renamedIndices = newHashMap();
         for (String index : filteredIndices) {
             String renamedIndex = index;

src/main/java/org/elasticsearch/snapshots/Snapshot.java

@@ -28,6 +28,7 @@ import org.elasticsearch.common.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.List;
 
 /**
  * Represent information about snapshot
@@ -42,7 +43,7 @@ public class Snapshot implements Comparable<Snapshot>, ToXContent {
 
     private final String reason;
 
-    private final ImmutableList<String> indices;
+    private final List<String> indices;
 
     private final long startTime;
 
@@ -52,12 +53,12 @@ public class Snapshot implements Comparable<Snapshot>, ToXContent {
 
     private final int successfulShards;
 
-    private final ImmutableList<SnapshotShardFailure> shardFailures;
+    private final List<SnapshotShardFailure> shardFailures;
 
-    private final static ImmutableList<SnapshotShardFailure> NO_FAILURES = ImmutableList.of();
+    private final static List<SnapshotShardFailure> NO_FAILURES = ImmutableList.of();
 
-    private Snapshot(String name, ImmutableList<String> indices, SnapshotState state, String reason, Version version, long startTime, long endTime,
+    private Snapshot(String name, List<String> indices, SnapshotState state, String reason, Version version, long startTime, long endTime,
-                              int totalShard, int successfulShards, ImmutableList<SnapshotShardFailure> shardFailures) {
+                              int totalShard, int successfulShards, List<SnapshotShardFailure> shardFailures) {
         assert name != null;
         assert indices != null;
         assert state != null;
@@ -75,17 +76,17 @@ public class Snapshot implements Comparable<Snapshot>, ToXContent {
     }
 
 
-    public Snapshot(String name, ImmutableList<String> indices, long startTime) {
+    public Snapshot(String name, List<String> indices, long startTime) {
         this(name, indices, SnapshotState.IN_PROGRESS, null, Version.CURRENT, startTime, 0L, 0, 0, NO_FAILURES);
     }
 
-    public Snapshot(String name, ImmutableList<String> indices, long startTime, String reason, long endTime,
+    public Snapshot(String name, List<String> indices, long startTime, String reason, long endTime,
-                             int totalShard, ImmutableList<SnapshotShardFailure> shardFailures) {
+                             int totalShard, List<SnapshotShardFailure> shardFailures) {
         this(name, indices, snapshotState(reason, shardFailures), reason, Version.CURRENT,
                 startTime, endTime, totalShard, totalShard - shardFailures.size(), shardFailures);
     }
 
-    private static SnapshotState snapshotState(String reason, ImmutableList<SnapshotShardFailure> shardFailures) {
+    private static SnapshotState snapshotState(String reason, List<SnapshotShardFailure> shardFailures) {
         if (reason == null) {
             if (shardFailures.isEmpty()) {
                 return SnapshotState.SUCCESS;
@@ -138,7 +139,7 @@ public class Snapshot implements Comparable<Snapshot>, ToXContent {
      *
      * @return list of indices
      */
-    public ImmutableList<String> indices() {
+    public List<String> indices() {
         return indices;
     }
 
@@ -183,7 +184,7 @@ public class Snapshot implements Comparable<Snapshot>, ToXContent {
     /**
      * Returns shard failures
      */
-    public ImmutableList<SnapshotShardFailure> shardFailures() {
+    public List<SnapshotShardFailure> shardFailures() {
         return shardFailures;
     }
 
@@ -275,7 +276,7 @@ public class Snapshot implements Comparable<Snapshot>, ToXContent {
         long endTime = 0;
         int totalShard = 0;
         int successfulShards = 0;
-        ImmutableList<SnapshotShardFailure> shardFailures = NO_FAILURES;
+        List<SnapshotShardFailure> shardFailures = NO_FAILURES;
 
         XContentParser.Token token = parser.currentToken();
         if (token == XContentParser.Token.START_OBJECT) {

src/main/java/org/elasticsearch/snapshots/SnapshotInfo.java

@@ -19,6 +19,8 @@
 package org.elasticsearch.snapshots;
 
 import java.io.IOException;
+import java.util.List;
+
 import org.elasticsearch.action.ShardOperationFailedException;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
@@ -44,7 +46,7 @@ public class SnapshotInfo implements ToXContent, Streamable {
 
     private String reason;
 
-    private ImmutableList<String> indices;
+    private List<String> indices;
 
     private long startTime;
 
@@ -54,7 +56,7 @@ public class SnapshotInfo implements ToXContent, Streamable {
 
     private int successfulShards;
 
-    private ImmutableList<SnapshotShardFailure> shardFailures;
+    private List<SnapshotShardFailure> shardFailures;
 
     SnapshotInfo() {
 
@@ -109,7 +111,7 @@ public class SnapshotInfo implements ToXContent, Streamable {
      *
      * @return list of indices
      */
-    public ImmutableList<String> indices() {
+    public List<String> indices() {
         return indices;
     }
 
@@ -165,7 +167,7 @@ public class SnapshotInfo implements ToXContent, Streamable {
      *
      * @return shard failures
      */
-    public ImmutableList<SnapshotShardFailure> shardFailures() {
+    public List<SnapshotShardFailure> shardFailures() {
         return shardFailures;
     }
 

src/main/java/org/elasticsearch/snapshots/SnapshotUtils.java

@@ -25,6 +25,7 @@ import org.elasticsearch.index.Index;
 import org.elasticsearch.indices.IndexMissingException;
 
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
 
 /**
@@ -40,7 +41,7 @@ public class SnapshotUtils {
      * @param indicesOptions    ignore indices flag
      * @return filtered out indices
      */
-    public static ImmutableList<String> filterIndices(ImmutableList<String> availableIndices, String[] selectedIndices, IndicesOptions indicesOptions) {
+    public static List<String> filterIndices(List<String> availableIndices, String[] selectedIndices, IndicesOptions indicesOptions) {
         if (selectedIndices == null || selectedIndices.length == 0) {
             return availableIndices;
         }

src/main/java/org/elasticsearch/snapshots/SnapshotsService.java

@@ -80,7 +80,7 @@ import static com.google.common.collect.Sets.newHashSet;
  * <li>When cluster state is updated the {@link #beginSnapshot(ClusterState, SnapshotMetaData.Entry, boolean, CreateSnapshotListener)} method
  * kicks in and initializes the snapshot in the repository and then populates list of shards that needs to be snapshotted in cluster state</li>
  * <li>Each data node is watching for these shards and when new shards scheduled for snapshotting appear in the cluster state, data nodes
- * start processing them through {@link #processIndexShardSnapshots(SnapshotMetaData)} method</li>
+ * start processing them through {@link SnapshotsService#processIndexShardSnapshots(ClusterChangedEvent)} method</li>
  * <li>Once shard snapshot is created data node updates state of the shard in the cluster state using the {@link #updateIndexShardSnapshotStatus(UpdateIndexShardSnapshotStatusRequest)} method</li>
  * <li>When last shard is completed master node in {@link #innerUpdateSnapshotState} method marks the snapshot as completed</li>
  * <li>After cluster state is updated, the {@link #endSnapshot(SnapshotMetaData.Entry)} finalizes snapshot in the repository,
@@ -135,7 +135,7 @@ public class SnapshotsService extends AbstractLifecycleComponent<SnapshotsServic
      * @throws SnapshotMissingException if snapshot is not found
      */
     public Snapshot snapshot(SnapshotId snapshotId) {
-        ImmutableList<SnapshotMetaData.Entry> entries = currentSnapshots(snapshotId.getRepository(), new String[]{snapshotId.getSnapshot()});
+        List<SnapshotMetaData.Entry> entries = currentSnapshots(snapshotId.getRepository(), new String[]{snapshotId.getSnapshot()});
         if (!entries.isEmpty()) {
             return inProgressSnapshot(entries.iterator().next());
         }
@@ -148,14 +148,14 @@ public class SnapshotsService extends AbstractLifecycleComponent<SnapshotsServic
      * @param repositoryName repository name
      * @return list of snapshots
      */
-    public ImmutableList<Snapshot> snapshots(String repositoryName) {
+    public List<Snapshot> snapshots(String repositoryName) {
         Set<Snapshot> snapshotSet = newHashSet();
-        ImmutableList<SnapshotMetaData.Entry> entries = currentSnapshots(repositoryName, null);
+        List<SnapshotMetaData.Entry> entries = currentSnapshots(repositoryName, null);
         for (SnapshotMetaData.Entry entry : entries) {
             snapshotSet.add(inProgressSnapshot(entry));
         }
         Repository repository = repositoriesService.repository(repositoryName);
-        ImmutableList<SnapshotId> snapshotIds = repository.snapshots();
+        List<SnapshotId> snapshotIds = repository.snapshots();
         for (SnapshotId snapshotId : snapshotIds) {
             snapshotSet.add(repository.readSnapshot(snapshotId));
         }
@@ -170,9 +170,9 @@ public class SnapshotsService extends AbstractLifecycleComponent<SnapshotsServic
      * @param repositoryName repository name
      * @return list of snapshots
      */
-    public ImmutableList<Snapshot> currentSnapshots(String repositoryName) {
+    public List<Snapshot> currentSnapshots(String repositoryName) {
         List<Snapshot> snapshotList = newArrayList();
-        ImmutableList<SnapshotMetaData.Entry> entries = currentSnapshots(repositoryName, null);
+        List<SnapshotMetaData.Entry> entries = currentSnapshots(repositoryName, null);
         for (SnapshotMetaData.Entry entry : entries) {
             snapshotList.add(inProgressSnapshot(entry));
         }
@@ -421,7 +421,7 @@ public class SnapshotsService extends AbstractLifecycleComponent<SnapshotsServic
      * @param snapshots  optional list of snapshots that will be used as a filter
      * @return list of metadata for currently running snapshots
      */
-    public ImmutableList<SnapshotMetaData.Entry> currentSnapshots(String repository, String[] snapshots) {
+    public List<SnapshotMetaData.Entry> currentSnapshots(String repository, String[] snapshots) {
         MetaData metaData = clusterService.state().metaData();
         SnapshotMetaData snapshotMetaData = metaData.custom(SnapshotMetaData.TYPE);
         if (snapshotMetaData == null || snapshotMetaData.entries().isEmpty()) {
@@ -524,7 +524,7 @@ public class SnapshotsService extends AbstractLifecycleComponent<SnapshotsServic
     }
 
 
-    private SnapshotShardFailure findShardFailure(ImmutableList<SnapshotShardFailure> shardFailures, ShardId shardId) {
+    private SnapshotShardFailure findShardFailure(List<SnapshotShardFailure> shardFailures, ShardId shardId) {
         for (SnapshotShardFailure shardFailure : shardFailures) {
             if (shardId.getIndex().equals(shardFailure.index()) && shardId.getId() == shardFailure.shardId()) {
                 return shardFailure;

src/test/java/org/elasticsearch/common/blobstore/BlobStoreTest.java

@@ -90,7 +90,7 @@ public class BlobStoreTest extends ElasticsearchTestCase {
         generatedBlobs.put(name, (long) length);
         byte[] data = createRandomBlob(container, name, length);
 
-        ImmutableMap<String, BlobMetaData> blobs = container.listBlobs();
+        Map<String, BlobMetaData> blobs = container.listBlobs();
         assertThat(blobs.size(), equalTo(numberOfFooBlobs + numberOfBarBlobs));
         for (Map.Entry<String, Long> generated : generatedBlobs.entrySet()) {
             BlobMetaData blobMetaData = blobs.get(generated.getKey());

src/test/java/org/elasticsearch/index/mapper/copyto/CopyToMapperTests.java

@@ -220,7 +220,7 @@ public class CopyToMapperTests extends ElasticsearchSingleNodeTest {
         DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
         DocumentMapper docMapperBefore = parser.parse(mappingBefore);
 
-        ImmutableList<String> fields = docMapperBefore.mappers().getMapper("copy_test").copyTo().copyToFields();
+        List<String> fields = docMapperBefore.mappers().getMapper("copy_test").copyTo().copyToFields();
 
         assertThat(fields.size(), equalTo(2));
         assertThat(fields.get(0), equalTo("foo"));

src/test/java/org/elasticsearch/snapshots/AbstractSnapshotTests.java

@@ -41,6 +41,7 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.SimpleFileVisitor;
 import java.nio.file.attribute.BasicFileAttributes;
+import java.util.List;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -100,7 +101,7 @@ public abstract class AbstractSnapshotTests extends ElasticsearchIntegrationTest
         long start = System.currentTimeMillis();
         SnapshotId snapshotId = new SnapshotId(repository, snapshot);
         while (System.currentTimeMillis() - start < timeout.millis()) {
-            ImmutableList<SnapshotInfo> snapshotInfos = client().admin().cluster().prepareGetSnapshots(repository).setSnapshots(snapshot).get().getSnapshots();
+            List<SnapshotInfo> snapshotInfos = client().admin().cluster().prepareGetSnapshots(repository).setSnapshots(snapshot).get().getSnapshots();
             assertThat(snapshotInfos.size(), equalTo(1));
             if (snapshotInfos.get(0).state().completed()) {
                 // Make sure that snapshot clean up operations are finished

src/test/java/org/elasticsearch/snapshots/RepositoriesTests.java

@@ -39,6 +39,7 @@ import org.elasticsearch.test.ElasticsearchIntegrationTest;
 import org.junit.Test;
 
 import java.nio.file.Path;
+import java.util.List;
 
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertThrows;
@@ -116,7 +117,7 @@ public class RepositoriesTests extends AbstractSnapshotTests {
         assertThat(repositoriesResponse.repositories().size(), equalTo(0));
     }
 
-    private RepositoryMetaData findRepository(ImmutableList<RepositoryMetaData> repositories, String name) {
+    private RepositoryMetaData findRepository(List<RepositoryMetaData> repositories, String name) {
         for (RepositoryMetaData repository : repositories) {
             if (repository.name().equals(name)) {
                 return repository;

src/test/java/org/elasticsearch/snapshots/SharedClusterSnapshotRestoreTests.java

@@ -1135,7 +1135,7 @@ public class SharedClusterSnapshotRestoreTests extends AbstractSnapshotTests {
         logger.info("Number of failed shards [{}]", snapshotInfo.shardFailures().size());
         logger.info("--> done");
 
-        ImmutableList<SnapshotInfo> snapshotInfos = client().admin().cluster().prepareGetSnapshots("test-repo").setSnapshots("test-snap").get().getSnapshots();
+        List<SnapshotInfo> snapshotInfos = client().admin().cluster().prepareGetSnapshots("test-repo").setSnapshots("test-snap").get().getSnapshots();
 
         assertThat(snapshotInfos.size(), equalTo(1));
         assertThat(snapshotInfos.get(0).state(), equalTo(SnapshotState.SUCCESS));
@@ -1218,7 +1218,7 @@ public class SharedClusterSnapshotRestoreTests extends AbstractSnapshotTests {
         logger.info("Number of failed shards [{}]", snapshotInfo.shardFailures().size());
         logger.info("--> done");
 
-        ImmutableList<SnapshotInfo> snapshotInfos = client().admin().cluster().prepareGetSnapshots("test-repo").setSnapshots("test-snap").get().getSnapshots();
+        List<SnapshotInfo> snapshotInfos = client().admin().cluster().prepareGetSnapshots("test-repo").setSnapshots("test-snap").get().getSnapshots();
 
         assertThat(snapshotInfos.size(), equalTo(1));
         assertThat(snapshotInfos.get(0).state(), equalTo(SnapshotState.SUCCESS));

src/test/java/org/elasticsearch/snapshots/SnapshotUtilsTests.java

@@ -23,6 +23,8 @@ import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.test.ElasticsearchTestCase;
 import org.junit.Test;
 
+import java.util.List;
+
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.containsInAnyOrder;
 
@@ -50,8 +52,8 @@ public class SnapshotUtilsTests extends ElasticsearchTestCase {
     }
 
     private void assertIndexNameFiltering(String[] indices, String[] filter, IndicesOptions indicesOptions, String[] expected) {
-        ImmutableList<String> indicesList = ImmutableList.copyOf(indices);
+        List<String> indicesList = ImmutableList.copyOf(indices);
-        ImmutableList<String> actual = SnapshotUtils.filterIndices(indicesList, filter, indicesOptions);
+        List<String> actual = SnapshotUtils.filterIndices(indicesList, filter, indicesOptions);
         assertThat(actual, containsInAnyOrder(expected));
     }
 }

src/test/java/org/elasticsearch/snapshots/mockstore/BlobContainerWrapper.java

@@ -26,6 +26,7 @@ import org.elasticsearch.common.blobstore.BlobPath;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.util.Map;
 
 /**
  *
@@ -68,12 +69,12 @@ public class BlobContainerWrapper implements BlobContainer {
     }
 
     @Override
-    public ImmutableMap<String, BlobMetaData> listBlobs() throws IOException {
+    public Map<String, BlobMetaData> listBlobs() throws IOException {
         return delegate.listBlobs();
     }
 
     @Override
-    public ImmutableMap<String, BlobMetaData> listBlobsByPrefix(String blobNamePrefix) throws IOException {
+    public Map<String, BlobMetaData> listBlobsByPrefix(String blobNamePrefix) throws IOException {
         return delegate.listBlobsByPrefix(blobNamePrefix);
     }
 

src/test/java/org/elasticsearch/snapshots/mockstore/MockRepository.java

@@ -46,6 +46,8 @@ import java.io.UnsupportedEncodingException;
 import java.nio.file.Path;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
+import java.util.List;
+import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.atomic.AtomicLong;
@@ -95,7 +97,7 @@ public class MockRepository extends FsRepository {
     }
 
     @Override
-    public void initializeSnapshot(SnapshotId snapshotId, ImmutableList<String> indices, MetaData metaData) {
+    public void initializeSnapshot(SnapshotId snapshotId, List<String> indices, MetaData metaData) {
         if (blockOnInitialization ) {
             blockExecution();
         }
@@ -292,13 +294,13 @@ public class MockRepository extends FsRepository {
             }
 
             @Override
-            public ImmutableMap<String, BlobMetaData> listBlobs() throws IOException {
+            public Map<String, BlobMetaData> listBlobs() throws IOException {
                 maybeIOExceptionOrBlock("");
                 return super.listBlobs();
             }
 
             @Override
-            public ImmutableMap<String, BlobMetaData> listBlobsByPrefix(String blobNamePrefix) throws IOException {
+            public Map<String, BlobMetaData> listBlobsByPrefix(String blobNamePrefix) throws IOException {
                 maybeIOExceptionOrBlock(blobNamePrefix);
                 return super.listBlobsByPrefix(blobNamePrefix);
             }