Remove and forbid use of Collections#shuffle(List) and Random#<init>()

This commit removes and now forbids all uses of
Collections#shuffle(List) and Random#<init>() across the codebase. The
rationale for removing and forbidding these methods is to increase test
reproducibility. As these methods use non-reproducible seeds, production
code and tests that rely on these methods contribute to
non-reproducbility of tests.

Instead of Collections#shuffle(List) the method
Collections#shuffle(List, Random) can be used. All that is required then
is a reproducible source of randomness. Consequently, the utility class
Randomness has been added to assist in creating reproducible sources of
randomness.

Instead of Random#<init>(), Random#<init>(long) with a reproducible seed
or the aforementioned Randomess class can be used.

Closes #15287

buildSrc/src/main/resources/forbidden/all-signatures.txt

@@ -123,3 +123,6 @@ java.lang.System#getProperties() @ Use BootstrapInfo.getSystemProperties for a r
 java.util.Collections#EMPTY_LIST
 java.util.Collections#EMPTY_MAP
 java.util.Collections#EMPTY_SET
+
+java.util.Collections#shuffle(java.util.List) @ Use java.util.Collections#shuffle(java.util.List, java.util.Random) with a reproducible source of randomness
+java.util.Random#<init>() @ Use org.elasticsearch.common.random.Randomness#create for reproducible sources of randomness

core/src/main/java/org/elasticsearch/cluster/routing/RoutingNodes.java

@@ -27,18 +27,11 @@ import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.block.ClusterBlocks;
 import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.cluster.node.DiscoveryNode;
+import org.elasticsearch.common.Randomness;
 import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.index.shard.ShardId;
 
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
 import java.util.function.Predicate;
 
 /**
@@ -671,7 +664,7 @@ public class RoutingNodes implements Iterable<RoutingNode> {
         }
 
         public void shuffle() {
-            Collections.shuffle(unassigned);
+            Randomness.shuffle(unassigned);
         }
 
         /**

core/src/main/java/org/elasticsearch/cluster/routing/allocation/AllocationService.java

@@ -39,15 +39,12 @@ import org.elasticsearch.cluster.routing.allocation.allocator.ShardsAllocators;
 import org.elasticsearch.cluster.routing.allocation.command.AllocationCommands;
 import org.elasticsearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.elasticsearch.cluster.routing.allocation.decider.Decision;
+import org.elasticsearch.common.Randomness;
 import org.elasticsearch.common.component.AbstractComponent;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.settings.Settings;
 
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collections;
-import java.util.List;
-import java.util.Objects;
-import java.util.Set;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 

core/src/main/java/org/elasticsearch/common/Randomness.java

@@ -0,0 +1,132 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.common;
+
+import org.elasticsearch.common.settings.Settings;
+
+import java.lang.reflect.Method;
+import java.security.SecureRandom;
+import java.util.Collections;
+import java.util.List;
+import java.util.Random;
+
+/**
+ * Provides factory methods for producing reproducible sources of
+ * randomness. Reproducible sources of randomness contribute to
+ * reproducible tests. When running the Elasticsearch test suite, the
+ * test runner will establish a global random seed accessible via the
+ * system property "tests.seed". By seeding a random number generator
+ * with this global seed, we ensure that instances of Random produced
+ * with this class produce reproducible sources of randomness under
+ * when running under the Elasticsearch test suite. Alternatively,
+ * a reproducible source of randomness can be produced by providing a
+ * setting a reproducible seed. When running the Elasticsearch server
+ * process, non-reproducible sources of randomness are provided (unless
+ * a setting is provided for a module that exposes a seed setting (e.g.,
+ * DiscoveryService#SETTING_DISCOVERY_SEED)).
+ */
+public final class Randomness {
+    private static final SecureRandom SR = new SecureRandom();
+    private static final Method currentMethod;
+    private static final Method getRandomMethod;
+
+    static {
+        Method maybeCurrentMethod;
+        Method maybeGetRandomMethod;
+        try {
+            Class<?> clazz = Class.forName("com.carrotsearch.randomizedtesting.RandomizedContext");
+            maybeCurrentMethod = clazz.getMethod("current");
+            maybeGetRandomMethod = clazz.getMethod("getRandom");
+        } catch (Throwable t) {
+            maybeCurrentMethod = null;
+            maybeGetRandomMethod = null;
+        }
+        currentMethod = maybeCurrentMethod;
+        getRandomMethod = maybeGetRandomMethod;
+    }
+
+    private Randomness() {}
+
+    /**
+     * Provides a reproducible source of randomness seeded by a long
+     * seed in the settings with the key setting.
+     *
+     * @param settings the settings containing the seed
+     * @param setting  the key to access the seed
+     * @return a reproducible source of randomness
+     */
+    public static Random get(Settings settings, String setting) {
+        Long maybeSeed = settings.getAsLong(setting, null);
+        if (maybeSeed != null) {
+            return new Random(maybeSeed);
+        } else {
+            return get();
+        }
+    }
+
+    /**
+     * Provides a source of randomness that is reproducible when
+     * running under the Elasticsearch test suite, and otherwise
+     * produces a non-reproducible source of randomness. Reproducible
+     * sources of randomness are created when the system property
+     * "tests.seed" is set and the security policy allows reading this
+     * system property. Otherwise, non-reproducible sources of
+     * randomness are created.
+     *
+     * @return a source of randomness
+     * @throws IllegalStateException if running tests but was not able
+     *                               to acquire an instance of Random from
+     *                               RandomizedContext or tests are
+     *                               running but tests.seed is not set
+     */
+    public static Random get() {
+        if (currentMethod != null && getRandomMethod != null) {
+            try {
+                Object randomizedContext = currentMethod.invoke(null);
+                return (Random) getRandomMethod.invoke(randomizedContext);
+            } catch (ReflectiveOperationException e) {
+                // unexpected, bail
+                throw new IllegalStateException("running tests but failed to invoke RandomizedContext#getRandom", e);
+            }
+        } else {
+            return getWithoutSeed();
+        }
+    }
+
+    private static ThreadLocal<Random> LOCAL;
+
+    private static Random getWithoutSeed() {
+        assert currentMethod == null && getRandomMethod == null : "running under tests but tried to create non-reproducible random";
+        if (LOCAL.get() == null) {
+            byte[] bytes = SR.generateSeed(8);
+            long accumulator = 0;
+            for (int i = 0; i < bytes.length; i++) {
+                accumulator = (accumulator << 8) + bytes[i] & 0xFFL;
+            }
+            final long seed = accumulator;
+            LOCAL = ThreadLocal.withInitial(() -> new Random(seed));
+        }
+        return LOCAL.get();
+    }
+
+    public static void shuffle(List<?> list) {
+        Collections.shuffle(list, get());
+    }
+}

core/src/main/java/org/elasticsearch/discovery/DiscoveryService.java

@@ -23,6 +23,7 @@ import org.elasticsearch.ElasticsearchTimeoutException;
 import org.elasticsearch.cluster.ClusterChangedEvent;
 import org.elasticsearch.cluster.block.ClusterBlock;
 import org.elasticsearch.cluster.node.DiscoveryNode;
+import org.elasticsearch.common.Randomness;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.component.AbstractLifecycleComponent;
 import org.elasticsearch.common.inject.Inject;
@@ -41,7 +42,6 @@ public class DiscoveryService extends AbstractLifecycleComponent<DiscoveryServic
     public static final String SETTING_INITIAL_STATE_TIMEOUT = "discovery.initial_state_timeout";
     public static final String SETTING_DISCOVERY_SEED = "discovery.id.seed";
 
-
     private static class InitialStateListener implements InitialStateDiscoveryListener {
 
         private final CountDownLatch latch = new CountDownLatch(1);
@@ -132,10 +132,7 @@ public class DiscoveryService extends AbstractLifecycleComponent<DiscoveryServic
     }
 
     public static String generateNodeId(Settings settings) {
-        String seed = settings.get(DiscoveryService.SETTING_DISCOVERY_SEED);
+        Random random = Randomness.get(settings, DiscoveryService.SETTING_DISCOVERY_SEED);
-        if (seed != null) {
+        return Strings.randomBase64UUID(random);
-            return Strings.randomBase64UUID(new Random(Long.parseLong(seed)));
-        }
-        return Strings.randomBase64UUID();
     }
 }

core/src/main/java/org/elasticsearch/plugins/PluginManager.java

@@ -22,6 +22,7 @@ package org.elasticsearch.plugins;
 import org.apache.lucene.util.IOUtils;
 import org.elasticsearch.*;
 import org.elasticsearch.bootstrap.JarHell;
+import org.elasticsearch.common.Randomness;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.cli.Terminal;
 import org.elasticsearch.common.collect.Tuple;
@@ -66,7 +67,7 @@ public class PluginManager {
             "plugin",
             "plugin.bat",
             "service.bat"));
-    
+
     static final Set<String> MODULES = unmodifiableSet(newHashSet(
             "lang-expression",
             "lang-groovy"));
@@ -124,7 +125,7 @@ public class PluginManager {
             checkForForbiddenName(pluginHandle.name);
         } else {
             // if we have no name but url, use temporary name that will be overwritten later
-            pluginHandle = new PluginHandle("temp_name" + new Random().nextInt(), null, null);
+            pluginHandle = new PluginHandle("temp_name" + Randomness.get().nextInt(), null, null);
         }
 
         Path pluginFile = download(pluginHandle, terminal);
@@ -224,7 +225,7 @@ public class PluginManager {
         PluginInfo info = PluginInfo.readFromProperties(root);
         terminal.println(VERBOSE, "%s", info);
 
-        // don't let luser install plugin as a module... 
+        // don't let luser install plugin as a module...
         // they might be unavoidably in maven central and are packaged up the same way)
         if (MODULES.contains(info.getName())) {
             throw new IOException("plugin '" + info.getName() + "' cannot be installed like this, it is a system module");

core/src/test/java/org/apache/lucene/queries/BlendedTermQueryTests.java

@@ -23,19 +23,8 @@ import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.FieldType;
 import org.apache.lucene.document.TextField;
-import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.*;
-import org.apache.lucene.index.IndexOptions;
+import org.apache.lucene.search.*;
-import org.apache.lucene.index.IndexWriter;
-import org.apache.lucene.index.MultiReader;
-import org.apache.lucene.index.Term;
-import org.apache.lucene.search.BooleanClause;
-import org.apache.lucene.search.BooleanQuery;
-import org.apache.lucene.search.DisjunctionMaxQuery;
-import org.apache.lucene.search.IndexSearcher;
-import org.apache.lucene.search.QueryUtils;
-import org.apache.lucene.search.ScoreDoc;
-import org.apache.lucene.search.TermQuery;
-import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.search.similarities.BM25Similarity;
 import org.apache.lucene.search.similarities.DefaultSimilarity;
 import org.apache.lucene.search.similarities.Similarity;
@@ -44,11 +33,7 @@ import org.apache.lucene.util.TestUtil;
 import org.elasticsearch.test.ESTestCase;
 
 import java.io.IOException;
-import java.util.Arrays;
+import java.util.*;
-import java.util.Collections;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
 
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.equalTo;

core/src/test/java/org/elasticsearch/action/admin/indices/shards/IndicesShardStoreResponseTests.java

@@ -26,20 +26,12 @@ import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.collect.ImmutableOpenIntMap;
 import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.common.transport.DummyTransportAddress;
-import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.*;
-import org.elasticsearch.common.xcontent.XContentBuilder;
-import org.elasticsearch.common.xcontent.XContentFactory;
-import org.elasticsearch.common.xcontent.XContentParser;
-import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.transport.NodeDisconnectedException;
 
 import java.io.IOException;
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
 
 import static org.hamcrest.Matchers.equalTo;
 
@@ -119,7 +111,7 @@ public class IndicesShardStoreResponseTests extends ESTestCase {
         orderedStoreStatuses.add(new IndicesShardStoresResponse.StoreStatus(node1, 3, IndicesShardStoresResponse.StoreStatus.Allocation.REPLICA, new IOException("corrupted")));
 
         List<IndicesShardStoresResponse.StoreStatus> storeStatuses = new ArrayList<>(orderedStoreStatuses);
-        Collections.shuffle(storeStatuses);
+        Collections.shuffle(storeStatuses, random());
         CollectionUtil.timSort(storeStatuses);
         assertThat(storeStatuses, equalTo(orderedStoreStatuses));
     }

core/src/test/java/org/elasticsearch/bwcompat/OldIndexBackwardsCompatibilityIT.java

@@ -32,8 +32,6 @@ import org.elasticsearch.action.admin.indices.upgrade.UpgradeIT;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.action.search.SearchRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
-import org.elasticsearch.cluster.ClusterState;
-import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.io.FileSystemUtils;
 import org.elasticsearch.common.logging.ESLogger;
 import org.elasticsearch.common.settings.Settings;
@@ -62,23 +60,12 @@ import org.junit.Before;
 
 import java.io.IOException;
 import java.io.InputStream;
-import java.nio.file.DirectoryStream;
+import java.nio.file.*;
-import java.nio.file.FileVisitResult;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.nio.file.SimpleFileVisitor;
 import java.nio.file.attribute.BasicFileAttributes;
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collections;
-import java.util.List;
-import java.util.Locale;
-import java.util.Map;
-import java.util.SortedSet;
-import java.util.TreeSet;
 
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertNoFailures;
-import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
 
 // needs at least 2 nodes since it bumps replicas to 1
@@ -271,7 +258,7 @@ public class OldIndexBackwardsCompatibilityIT extends ESIntegTestCase {
     public void testOldIndexes() throws Exception {
         setupCluster();
 
-        Collections.shuffle(indexes, getRandom());
+        Collections.shuffle(indexes, random());
         for (String index : indexes) {
             long startTime = System.currentTimeMillis();
             logger.info("--> Testing old index " + index);

core/src/test/java/org/elasticsearch/cluster/node/DiscoveryNodeFiltersTests.java

@@ -29,11 +29,7 @@ import org.junit.BeforeClass;
 
 import java.net.InetAddress;
 import java.net.UnknownHostException;
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
@@ -246,7 +242,7 @@ public class DiscoveryNodeFiltersTests extends ESTestCase {
     private Settings shuffleSettings(Settings source) {
         Settings.Builder settings = Settings.settingsBuilder();
         List<String> keys = new ArrayList<>(source.getAsMap().keySet());
-        Collections.shuffle(keys, getRandom());
+        Collections.shuffle(keys, random());
         for (String o : keys) {
             settings.put(o, source.getAsMap().get(o));
         }

core/src/test/java/org/elasticsearch/cluster/routing/DelayedAllocationIT.java

@@ -170,7 +170,7 @@ public class DelayedAllocationIT extends ESIntegTestCase {
     private String findNodeWithShard() {
         ClusterState state = client().admin().cluster().prepareState().get().getState();
         List<ShardRouting> startedShards = state.routingTable().shardsWithState(ShardRoutingState.STARTED);
-        Collections.shuffle(startedShards, getRandom());
+        Collections.shuffle(startedShards,random());
         return state.nodes().get(startedShards.get(0).currentNodeId()).getName();
     }
 }

core/src/test/java/org/elasticsearch/cluster/routing/allocation/AddIncrementallyTests.java

@@ -20,7 +20,6 @@
 package org.elasticsearch.cluster.routing.allocation;
 
 import com.carrotsearch.hppc.cursors.ObjectCursor;
-
 import org.elasticsearch.Version;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
@@ -388,7 +387,7 @@ public class AddIncrementallyTests extends ESAllocationTestCase {
         logger.info("Removing [{}] nodes", numNodes);
         DiscoveryNodes.Builder nodes = DiscoveryNodes.builder(clusterState.nodes());
         ArrayList<DiscoveryNode> discoveryNodes = CollectionUtils.iterableAsArrayList(clusterState.nodes());
-        Collections.shuffle(discoveryNodes, getRandom());
+        Collections.shuffle(discoveryNodes, random());
         for (DiscoveryNode node : discoveryNodes) {
             nodes.remove(node.id());
             numNodes--;

core/src/test/java/org/elasticsearch/cluster/routing/allocation/NodeVersionAllocationDeciderTests.java

@@ -39,15 +39,10 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
-import static org.elasticsearch.cluster.routing.ShardRoutingState.INITIALIZING;
+import static org.elasticsearch.cluster.routing.ShardRoutingState.*;
-import static org.elasticsearch.cluster.routing.ShardRoutingState.STARTED;
-import static org.elasticsearch.cluster.routing.ShardRoutingState.UNASSIGNED;
 import static org.elasticsearch.common.settings.Settings.settingsBuilder;
 import static org.elasticsearch.test.VersionUtils.randomVersion;
-import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.*;
-import static org.hamcrest.Matchers.is;
-import static org.hamcrest.Matchers.notNullValue;
-import static org.hamcrest.Matchers.nullValue;
 
 /**
  *
@@ -199,7 +194,7 @@ public class NodeVersionAllocationDeciderTests extends ESAllocationTestCase {
             DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder();
             int numNodes = between(1, 20);
             if (nodes.size() > numNodes) {
-                Collections.shuffle(nodes, getRandom());
+                Collections.shuffle(nodes, random());
                 nodes = nodes.subList(0, numNodes);
             } else {
                 for (int j = nodes.size(); j < numNodes; j++) {

core/src/test/java/org/elasticsearch/common/lucene/LuceneTests.java

@@ -17,20 +17,14 @@
  * under the License.
  */
 package org.elasticsearch.common.lucene;
+
 import org.apache.lucene.analysis.MockAnalyzer;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.Field.Store;
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.document.TextField;
-import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.*;
-import org.apache.lucene.index.IndexWriter;
-import org.apache.lucene.index.IndexWriterConfig;
-import org.apache.lucene.index.NoDeletionPolicy;
-import org.apache.lucene.index.NoMergePolicy;
-import org.apache.lucene.index.RandomIndexWriter;
-import org.apache.lucene.index.SegmentInfos;
-import org.apache.lucene.index.Term;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.TermQuery;
@@ -41,11 +35,7 @@ import org.apache.lucene.util.Version;
 import org.elasticsearch.test.ESTestCase;
 
 import java.io.IOException;
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collections;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicBoolean;
 

core/src/test/java/org/elasticsearch/common/lucene/index/FreqTermsEnumTests.java

@@ -24,13 +24,7 @@ import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.document.TextField;
-import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.*;
-import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.index.IndexWriter;
-import org.apache.lucene.index.IndexWriterConfig;
-import org.apache.lucene.index.IndexableField;
-import org.apache.lucene.index.NoMergePolicy;
-import org.apache.lucene.index.Term;
 import org.apache.lucene.queries.TermsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
@@ -42,14 +36,7 @@ import org.elasticsearch.test.ESTestCase;
 import org.junit.After;
 import org.junit.Before;
 
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
 
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
@@ -201,7 +188,7 @@ public class FreqTermsEnumTests extends ESTestCase {
         for (int i = 0; i < cycles; i++) {
             List<String> terms = new ArrayList<>(Arrays.asList(this.terms));
 
-           Collections.shuffle(terms, getRandom());
+           Collections.shuffle(terms, random());
             for (String term : terms) {
                 if (!termsEnum.seekExact(new BytesRef(term))) {
                     assertThat("term : " + term, reference.get(term).docFreq, is(0));

core/src/test/java/org/elasticsearch/common/util/CollectionUtilsTests.java

@@ -25,14 +25,7 @@ import org.apache.lucene.util.BytesRefBuilder;
 import org.apache.lucene.util.Counter;
 import org.elasticsearch.test.ESTestCase;
 
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.HashSet;
-import java.util.Iterator;
-import java.util.List;
-import java.util.SortedSet;
-import java.util.TreeSet;
 
 import static org.elasticsearch.common.util.CollectionUtils.eagerPartition;
 import static org.hamcrest.Matchers.equalTo;
@@ -80,7 +73,7 @@ public class CollectionUtilsTests extends ESTestCase {
             array.append(new BytesRef(s));
         }
         if (randomBoolean()) {
-            Collections.shuffle(tmpList, getRandom());
+            Collections.shuffle(tmpList, random());
             for (BytesRef ref : tmpList) {
                 array.append(ref);
             }
@@ -111,7 +104,7 @@ public class CollectionUtilsTests extends ESTestCase {
             array.append(new BytesRef(s));
         }
         if (randomBoolean()) {
-            Collections.shuffle(values, getRandom());
+            Collections.shuffle(values, random());
         }
         int[] indices = new int[array.size()];
         for (int i = 0; i < indices.length; i++) {

core/src/test/java/org/elasticsearch/common/util/concurrent/PrioritizedExecutorsTests.java

@@ -27,13 +27,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
-import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.*;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.concurrent.PriorityBlockingQueue;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.ScheduledThreadPoolExecutor;
-import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import static org.hamcrest.Matchers.equalTo;
@@ -46,7 +40,7 @@ public class PrioritizedExecutorsTests extends ESTestCase {
     public void testPriorityQueue() throws Exception {
         PriorityBlockingQueue<Priority> queue = new PriorityBlockingQueue<>();
         List<Priority> priorities = Arrays.asList(Priority.values());
-        Collections.shuffle(priorities);
+        Collections.shuffle(priorities, random());
 
         for (Priority priority : priorities) {
             queue.add(priority);

core/src/test/java/org/elasticsearch/discovery/DiscoveryWithServiceDisruptionsIT.java

@@ -473,7 +473,7 @@ public class DiscoveryWithServiceDisruptionsIT extends ESIntegTestCase {
                 docsPerIndexer = 1 + randomInt(5);
                 logger.info("indexing " + docsPerIndexer + " docs per indexer during partition");
                 countDownLatchRef.set(new CountDownLatch(docsPerIndexer * indexers.size()));
-                Collections.shuffle(semaphores);
+                Collections.shuffle(semaphores, random());
                 for (Semaphore semaphore : semaphores) {
                     assertThat(semaphore.availablePermits(), equalTo(0));
                     semaphore.release(docsPerIndexer);
@@ -683,7 +683,7 @@ public class DiscoveryWithServiceDisruptionsIT extends ESIntegTestCase {
         ensureGreen("test");
 
         nodes = new ArrayList<>(nodes);
-        Collections.shuffle(nodes, getRandom());
+        Collections.shuffle(nodes, random());
         String isolatedNode = nodes.get(0);
         String notIsolatedNode = nodes.get(1);
 
@@ -1038,7 +1038,7 @@ public class DiscoveryWithServiceDisruptionsIT extends ESIntegTestCase {
                 new NetworkDisconnectPartition(getRandom()),
                 new SlowClusterStateProcessing(getRandom())
         );
-        Collections.shuffle(list);
+        Collections.shuffle(list, random());
         setDisruptionScheme(list.get(0));
         return list.get(0);
     }

core/src/test/java/org/elasticsearch/discovery/zen/ElectMasterServiceTests.java

@@ -26,11 +26,7 @@ import org.elasticsearch.common.transport.DummyTransportAddress;
 import org.elasticsearch.discovery.zen.elect.ElectMasterService;
 import org.elasticsearch.test.ESTestCase;
 
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
 
 public class ElectMasterServiceTests extends ESTestCase {
 
@@ -53,7 +49,7 @@ public class ElectMasterServiceTests extends ESTestCase {
             nodes.add(node);
         }
 
-        Collections.shuffle(nodes, getRandom());
+        Collections.shuffle(nodes, random());
         return nodes;
     }
 

core/src/test/java/org/elasticsearch/discovery/zen/NodeJoinControllerTests.java

@@ -244,7 +244,7 @@ public class NodeJoinControllerTests extends ESTestCase {
 
         // add
 
-        Collections.shuffle(nodesToJoin);
+        Collections.shuffle(nodesToJoin, random());
         logger.debug("--> joining [{}] unique master nodes. Total of [{}] join requests", initialJoins, nodesToJoin.size());
         for (DiscoveryNode node : nodesToJoin) {
             pendingJoins.add(joinNodeAsync(node));
@@ -269,7 +269,7 @@ public class NodeJoinControllerTests extends ESTestCase {
             }
         }
 
-        Collections.shuffle(nodesToJoin);
+        Collections.shuffle(nodesToJoin, random());
         logger.debug("--> joining [{}] nodes, with repetition a total of [{}]", finalJoins, nodesToJoin.size());
         for (DiscoveryNode node : nodesToJoin) {
             pendingJoins.add(joinNodeAsync(node));
@@ -316,7 +316,7 @@ public class NodeJoinControllerTests extends ESTestCase {
                 nodesToJoin.add(node);
             }
         }
-        Collections.shuffle(nodesToJoin);
+        Collections.shuffle(nodesToJoin, random());
         logger.debug("--> joining [{}] nodes, with repetition a total of [{}]", initialJoins, nodesToJoin.size());
         for (DiscoveryNode node : nodesToJoin) {
             pendingJoins.add(joinNodeAsync(node));

core/src/test/java/org/elasticsearch/discovery/zen/ZenPingTests.java

@@ -62,7 +62,7 @@ public class ZenPingTests extends ESTestCase {
         }
 
         // shuffle
-        Collections.shuffle(pings);
+        Collections.shuffle(pings, random());
 
         ZenPing.PingCollection collection = new ZenPing.PingCollection();
         collection.addPings(pings.toArray(new ZenPing.PingResponse[pings.size()]));

core/src/test/java/org/elasticsearch/discovery/zen/publish/PublishClusterStateActionTests.java

@@ -21,17 +21,14 @@ package org.elasticsearch.discovery.zen.publish;
 
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.Version;
-import org.elasticsearch.cluster.ClusterChangedEvent;
+import org.elasticsearch.cluster.*;
-import org.elasticsearch.cluster.ClusterName;
-import org.elasticsearch.cluster.ClusterState;
-import org.elasticsearch.cluster.ClusterStateListener;
-import org.elasticsearch.cluster.Diff;
 import org.elasticsearch.cluster.block.ClusterBlocks;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.node.DiscoveryNodes;
 import org.elasticsearch.common.Nullable;
+import org.elasticsearch.common.Randomness;
 import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
@@ -47,35 +44,20 @@ import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.test.junit.annotations.TestLogging;
 import org.elasticsearch.test.transport.MockTransportService;
 import org.elasticsearch.threadpool.ThreadPool;
-import org.elasticsearch.transport.BytesTransportRequest;
+import org.elasticsearch.transport.*;
-import org.elasticsearch.transport.TransportChannel;
-import org.elasticsearch.transport.TransportConnectionListener;
-import org.elasticsearch.transport.TransportResponse;
-import org.elasticsearch.transport.TransportResponseOptions;
-import org.elasticsearch.transport.TransportService;
 import org.elasticsearch.transport.local.LocalTransport;
 import org.junit.After;
 import org.junit.Before;
 
 import java.io.IOException;
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 
-import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.*;
-import static org.hamcrest.Matchers.emptyIterable;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.not;
-import static org.hamcrest.Matchers.notNullValue;
-import static org.hamcrest.Matchers.nullValue;
 
 @TestLogging("discovery.zen.publish:TRACE")
 public class PublishClusterStateActionTests extends ESTestCase {
@@ -675,7 +657,7 @@ public class PublishClusterStateActionTests extends ESTestCase {
 
         logger.info("--> committing states");
 
-        Collections.shuffle(states, random());
+        Randomness.shuffle(states);
         for (ClusterState state : states) {
             node.action.handleCommitRequest(new PublishClusterStateAction.CommitClusterStateRequest(state.stateUUID()), channel);
             assertThat(channel.response.get(), equalTo((TransportResponse) TransportResponse.Empty.INSTANCE));

core/src/test/java/org/elasticsearch/gateway/MetaDataStateFormatTests.java

@@ -19,12 +19,7 @@
 package org.elasticsearch.gateway;
 
 import org.apache.lucene.codecs.CodecUtil;
-import org.apache.lucene.store.ChecksumIndexInput;
+import org.apache.lucene.store.*;
-import org.apache.lucene.store.Directory;
-import org.apache.lucene.store.IOContext;
-import org.apache.lucene.store.IndexInput;
-import org.apache.lucene.store.MockDirectoryWrapper;
-import org.apache.lucene.store.SimpleFSDirectory;
 import org.apache.lucene.util.LuceneTestCase;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.Version;
@@ -33,11 +28,7 @@ import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.common.io.FileSystemUtils;
 import org.elasticsearch.common.logging.ESLogger;
-import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.*;
-import org.elasticsearch.common.xcontent.XContentBuilder;
-import org.elasticsearch.common.xcontent.XContentFactory;
-import org.elasticsearch.common.xcontent.XContentParser;
-import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESTestCase;
 
 import java.io.IOException;
@@ -50,20 +41,10 @@ import java.nio.file.DirectoryStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
 import java.util.stream.StreamSupport;
 
-import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.*;
-import static org.hamcrest.Matchers.instanceOf;
-import static org.hamcrest.Matchers.is;
-import static org.hamcrest.Matchers.not;
-import static org.hamcrest.Matchers.notNullValue;
-import static org.hamcrest.Matchers.startsWith;
 
 @LuceneTestCase.SuppressFileSystems("ExtrasFS") // TODO: fix test to work with ExtrasFS
 public class MetaDataStateFormatTests extends ESTestCase {
@@ -349,7 +330,7 @@ public class MetaDataStateFormatTests extends ESTestCase {
 
         }
         List<Path> dirList = Arrays.asList(dirs);
-        Collections.shuffle(dirList, getRandom());
+        Collections.shuffle(dirList, random());
         MetaData loadedMetaData = format.loadLatestState(logger, dirList.toArray(new Path[0]));
         MetaData latestMetaData = meta.get(numStates-1);
         assertThat(loadedMetaData.clusterUUID(), not(equalTo("_na_")));

core/src/test/java/org/elasticsearch/index/mapper/all/SimpleAllMapperTests.java

@@ -49,21 +49,12 @@ import org.elasticsearch.test.ESSingleNodeTestCase;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
 
 import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.elasticsearch.test.StreamsUtils.copyToBytesFromClasspath;
 import static org.elasticsearch.test.StreamsUtils.copyToStringFromClasspath;
-import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.*;
-import static org.hamcrest.Matchers.empty;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.hasItem;
-import static org.hamcrest.Matchers.hasSize;
-import static org.hamcrest.Matchers.nullValue;
 
 public class SimpleAllMapperTests extends ESSingleNodeTestCase {
 
@@ -251,7 +242,7 @@ public class SimpleAllMapperTests extends ESSingleNodeTestCase {
             if (randomBoolean()) {
                 booleanOptionList.add(new Tuple<>("store_term_vector_payloads", tv_payloads = randomBoolean()));
             }
-            Collections.shuffle(booleanOptionList, getRandom());
+            Collections.shuffle(booleanOptionList, random());
             for (Tuple<String, Boolean> option : booleanOptionList) {
                 mappingBuilder.field(option.v1(), option.v2().booleanValue());
             }

core/src/test/java/org/elasticsearch/index/mapper/core/TokenCountFieldMapperTests.java

@@ -19,11 +19,7 @@
 
 package org.elasticsearch.index.mapper.core;
 
-import org.apache.lucene.analysis.Analyzer;
+import org.apache.lucene.analysis.*;
-import org.apache.lucene.analysis.CannedTokenStream;
-import org.apache.lucene.analysis.MockTokenizer;
-import org.apache.lucene.analysis.Token;
-import org.apache.lucene.analysis.TokenStream;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.index.mapper.DocumentMapper;
 import org.elasticsearch.index.mapper.DocumentMapperParser;
@@ -85,7 +81,7 @@ public class TokenCountFieldMapperTests extends ESSingleNodeTestCase {
         t2.setPositionIncrement(2);  // Count funny tokens with more than one increment
         int finalTokenIncrement = 4; // Count the final token increment on the rare token streams that have them
         Token[] tokens = new Token[] {t1, t2, t3};
-        Collections.shuffle(Arrays.asList(tokens), getRandom());
+        Collections.shuffle(Arrays.asList(tokens), random());
         final TokenStream tokenStream = new CannedTokenStream(finalTokenIncrement, 0, tokens);
         // TODO: we have no CannedAnalyzer?
         Analyzer analyzer = new Analyzer() {

core/src/test/java/org/elasticsearch/index/mapper/multifield/MultiFieldTests.java

@@ -479,7 +479,7 @@ public class MultiFieldTests extends ESSingleNodeTestCase {
             .startObject("my_field").field("type", "string").startObject("fields").startObject(MY_MULTI_FIELD)
             .field("type", "string").startObject("fielddata");
         String[] keys = possibleSettings.keySet().toArray(new String[]{});
-        Collections.shuffle(Arrays.asList(keys));
+        Collections.shuffle(Arrays.asList(keys), random());
         for(int i = randomIntBetween(0, possibleSettings.size()-1); i >= 0; --i)
             builder.field(keys[i], possibleSettings.get(keys[i]));
         builder.endObject().endObject().endObject().endObject().endObject().endObject().endObject();

core/src/test/java/org/elasticsearch/index/store/CorruptedFileIT.java

@@ -19,26 +19,21 @@
 package org.elasticsearch.index.store;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
-
 import org.apache.lucene.index.CheckIndex;
 import org.apache.lucene.index.IndexFileNames;
 import org.elasticsearch.action.admin.cluster.health.ClusterHealthResponse;
-import org.elasticsearch.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.action.admin.cluster.node.stats.NodeStats;
 import org.elasticsearch.action.admin.cluster.node.stats.NodesStatsResponse;
 import org.elasticsearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.elasticsearch.action.admin.cluster.state.ClusterStateResponse;
-import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.index.IndexRequestBuilder;
+import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.client.Requests;
 import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.node.DiscoveryNode;
-import org.elasticsearch.cluster.routing.GroupShardsIterator;
+import org.elasticsearch.cluster.routing.*;
-import org.elasticsearch.cluster.routing.IndexShardRoutingTable;
-import org.elasticsearch.cluster.routing.ShardIterator;
-import org.elasticsearch.cluster.routing.ShardRouting;
-import org.elasticsearch.cluster.routing.ShardRoutingState;
 import org.elasticsearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.elasticsearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
 import org.elasticsearch.common.Nullable;
@@ -48,7 +43,6 @@ import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.ByteSizeUnit;
-import org.elasticsearch.discovery.Discovery;
 import org.elasticsearch.gateway.PrimaryShardAllocator;
 import org.elasticsearch.index.shard.*;
 import org.elasticsearch.indices.recovery.RecoveryFileChunkRequest;
@@ -75,14 +69,7 @@ import java.nio.charset.StandardCharsets;
 import java.nio.file.DirectoryStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-import java.util.TreeSet;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutionException;
@@ -91,16 +78,8 @@ import java.util.concurrent.atomic.AtomicBoolean;
 
 import static org.elasticsearch.common.settings.Settings.settingsBuilder;
 import static org.elasticsearch.common.util.CollectionUtils.iterableAsArrayList;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
+import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.*;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAllSuccessful;
+import static org.hamcrest.Matchers.*;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertHitCount;
-import static org.hamcrest.Matchers.anyOf;
-import static org.hamcrest.Matchers.empty;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.greaterThanOrEqualTo;
-import static org.hamcrest.Matchers.is;
-import static org.hamcrest.Matchers.not;
-import static org.hamcrest.Matchers.notNullValue;
 
 @ESIntegTestCase.ClusterScope(scope = ESIntegTestCase.Scope.SUITE)
 public class CorruptedFileIT extends ESIntegTestCase {
@@ -320,7 +299,7 @@ public class CorruptedFileIT extends ESIntegTestCase {
         }
 
         assertThat(dataNodeStats.size(), greaterThanOrEqualTo(2));
-        Collections.shuffle(dataNodeStats, getRandom());
+        Collections.shuffle(dataNodeStats, random());
         NodeStats primariesNode = dataNodeStats.get(0);
         NodeStats unluckyNode = dataNodeStats.get(1);
         assertAcked(prepareCreate("test").setSettings(Settings.builder()
@@ -380,7 +359,7 @@ public class CorruptedFileIT extends ESIntegTestCase {
         }
 
         assertThat(dataNodeStats.size(), greaterThanOrEqualTo(2));
-        Collections.shuffle(dataNodeStats, getRandom());
+        Collections.shuffle(dataNodeStats, random());
         NodeStats primariesNode = dataNodeStats.get(0);
         NodeStats unluckyNode = dataNodeStats.get(1);
 

core/src/test/java/org/elasticsearch/indices/recovery/RecoveryStateTests.java

@@ -26,13 +26,7 @@ import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.Streamable;
 import org.elasticsearch.common.transport.DummyTransportAddress;
 import org.elasticsearch.index.shard.ShardId;
-import org.elasticsearch.indices.recovery.RecoveryState.File;
+import org.elasticsearch.indices.recovery.RecoveryState.*;
-import org.elasticsearch.indices.recovery.RecoveryState.Index;
-import org.elasticsearch.indices.recovery.RecoveryState.Stage;
-import org.elasticsearch.indices.recovery.RecoveryState.Timer;
-import org.elasticsearch.indices.recovery.RecoveryState.Translog;
-import org.elasticsearch.indices.recovery.RecoveryState.Type;
-import org.elasticsearch.indices.recovery.RecoveryState.VerifyIndex;
 import org.elasticsearch.test.ESTestCase;
 
 import java.io.IOException;
@@ -43,14 +37,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 
 import static org.elasticsearch.test.VersionUtils.randomVersion;
-import static org.hamcrest.Matchers.arrayContainingInAnyOrder;
+import static org.hamcrest.Matchers.*;
-import static org.hamcrest.Matchers.closeTo;
-import static org.hamcrest.Matchers.either;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.greaterThan;
-import static org.hamcrest.Matchers.greaterThanOrEqualTo;
-import static org.hamcrest.Matchers.lessThan;
-import static org.hamcrest.Matchers.lessThanOrEqualTo;
 
 public class RecoveryStateTests extends ESTestCase {
     abstract class Streamer<T extends Streamable> extends Thread {
@@ -201,7 +188,7 @@ public class RecoveryStateTests extends ESTestCase {
             }
         }
 
-        Collections.shuffle(Arrays.asList(files));
+        Collections.shuffle(Arrays.asList(files), random());
         final RecoveryState.Index index = new RecoveryState.Index();
 
         if (randomBoolean()) {

core/src/test/java/org/elasticsearch/recovery/TruncatedRecoveryIT.java

@@ -29,7 +29,6 @@ import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.ByteSizeUnit;
 import org.elasticsearch.common.unit.ByteSizeValue;
-import org.elasticsearch.discovery.Discovery;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.indices.recovery.IndexRecoveryIT;
 import org.elasticsearch.indices.recovery.RecoveryFileChunkRequest;
@@ -84,7 +83,7 @@ public class TruncatedRecoveryIT extends ESIntegTestCase {
             }
         }
         assertThat(dataNodeStats.size(), greaterThanOrEqualTo(2));
-        Collections.shuffle(dataNodeStats, getRandom());
+        Collections.shuffle(dataNodeStats, random());
         // we use 2 nodes a lucky and unlucky one
         // the lucky one holds the primary
         // the unlucky one gets the replica and the truncated leftovers

core/src/test/java/org/elasticsearch/search/suggest/CompletionSuggestSearchIT.java

@@ -942,13 +942,13 @@ public class CompletionSuggestSearchIT extends ESIntegTestCase {
 
     }
     public void assertSuggestions(String suggestion, String... suggestions) {
-        String suggestionName = RandomStrings.randomAsciiOfLength(new Random(), 10);
+        String suggestionName = RandomStrings.randomAsciiOfLength(random(), 10);
         CompletionSuggestionBuilder suggestionBuilder = SuggestBuilders.completionSuggestion(suggestionName).field(FIELD).text(suggestion).size(10);
         assertSuggestions(suggestionName, suggestionBuilder, suggestions);
     }
 
     public void assertSuggestionsNotInOrder(String suggestString, String... suggestions) {
-        String suggestionName = RandomStrings.randomAsciiOfLength(new Random(), 10);
+        String suggestionName = RandomStrings.randomAsciiOfLength(random(), 10);
         SuggestResponse suggestResponse = client().prepareSuggest(INDEX).addSuggestion(
                 SuggestBuilders.completionSuggestion(suggestionName).field(FIELD).text(suggestString).size(10)
         ).execute().actionGet();

modules/lang-groovy/src/test/java/org/elasticsearch/messy/tests/SimpleSortTests.java

@@ -48,58 +48,24 @@ import org.elasticsearch.script.groovy.GroovyPlugin;
 import org.elasticsearch.search.SearchHit;
 import org.elasticsearch.search.SearchHitField;
 import org.elasticsearch.search.builder.SearchSourceBuilder;
-import org.elasticsearch.search.sort.FieldSortBuilder;
+import org.elasticsearch.search.sort.*;
-import org.elasticsearch.search.sort.GeoDistanceSortBuilder;
-import org.elasticsearch.search.sort.ScriptSortBuilder;
-import org.elasticsearch.search.sort.SortBuilders;
-import org.elasticsearch.search.sort.SortOrder;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.VersionUtils;
 import org.elasticsearch.test.junit.annotations.TestLogging;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Locale;
 import java.util.Map.Entry;
-import java.util.Random;
-import java.util.Set;
-import java.util.TreeMap;
 import java.util.concurrent.ExecutionException;
 
+import static org.apache.lucene.util.GeoUtils.TOLERANCE;
 import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
-import static org.elasticsearch.index.query.QueryBuilders.functionScoreQuery;
+import static org.elasticsearch.index.query.QueryBuilders.*;
-import static org.elasticsearch.index.query.QueryBuilders.matchAllQuery;
-import static org.elasticsearch.index.query.QueryBuilders.termQuery;
 import static org.elasticsearch.index.query.functionscore.ScoreFunctionBuilders.fieldValueFactorFunction;
 import static org.elasticsearch.search.sort.SortBuilders.fieldSort;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
+import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.*;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertFirstHit;
+import static org.hamcrest.Matchers.*;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertHitCount;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertNoFailures;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertOrderedSearchHits;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertSearchResponse;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertSecondHit;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertSortValues;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.hasId;
-import static org.hamcrest.Matchers.closeTo;
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.greaterThan;
-import static org.hamcrest.Matchers.greaterThanOrEqualTo;
-import static org.hamcrest.Matchers.is;
-import static org.hamcrest.Matchers.lessThan;
-import static org.hamcrest.Matchers.lessThanOrEqualTo;
-import static org.hamcrest.Matchers.not;
-import static org.hamcrest.Matchers.notNullValue;
-import static org.hamcrest.Matchers.nullValue;
-
-import static org.apache.lucene.util.GeoUtils.TOLERANCE;
 
 /**
  *
@@ -530,7 +496,7 @@ public class SimpleSortTests extends ESIntegTestCase {
                     .endObject());
             builders.add(builder);
         }
-        Collections.shuffle(builders, random);
+        Randomness.shuffle(builders);
         for (IndexRequestBuilder builder : builders) {
             builder.execute().actionGet();
             if (random.nextBoolean()) {

plugins/discovery-ec2/src/main/java/org/elasticsearch/cloud/aws/AwsEc2ServiceImpl.java

@@ -32,6 +32,7 @@ import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.cloud.aws.network.Ec2NameResolver;
 import org.elasticsearch.cloud.aws.node.Ec2CustomNodeAttributes;
 import org.elasticsearch.cluster.node.DiscoveryNodeService;
+import org.elasticsearch.common.Randomness;
 import org.elasticsearch.common.component.AbstractLifecycleComponent;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.network.NetworkService;
@@ -119,7 +120,7 @@ public class AwsEc2ServiceImpl extends AbstractLifecycleComponent<AwsEc2Service>
         }
 
         // Increase the number of retries in case of 5xx API responses
-        final Random rand = new Random();
+        final Random rand = Randomness.get();
         RetryPolicy retryPolicy = new RetryPolicy(
                 RetryPolicy.RetryCondition.NO_RETRY_CONDITION,
                 new RetryPolicy.BackoffStrategy() {

qa/evil-tests/src/test/java/org/elasticsearch/tribe/TribeUnitTests.java

@@ -24,6 +24,7 @@ import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.common.SuppressForbidden;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.discovery.DiscoveryService;
 import org.elasticsearch.node.Node;
 import org.elasticsearch.node.internal.InternalSettingsPreparer;
 import org.elasticsearch.test.ESIntegTestCase;
@@ -57,8 +58,20 @@ public class TribeUnitTests extends ESTestCase {
             .put("node.mode", NODE_MODE)
             .put("path.home", createTempDir()).build();
 
-        tribe1 = new TribeClientNode(Settings.builder().put(baseSettings).put("cluster.name", "tribe1").put("name", "tribe1_node").build()).start();
+        tribe1 = new TribeClientNode(
-        tribe2 = new TribeClientNode(Settings.builder().put(baseSettings).put("cluster.name", "tribe2").put("name", "tribe2_node").build()).start();
+            Settings.builder()
+                .put(baseSettings)
+                .put("cluster.name", "tribe1")
+                .put("node.name", "tribe1_node")
+                .put(DiscoveryService.SETTING_DISCOVERY_SEED, random().nextLong())
+                .build()).start();
+        tribe2 = new TribeClientNode(
+            Settings.builder()
+                .put(baseSettings)
+                .put("cluster.name", "tribe2")
+                .put("node.name", "tribe2_node")
+                .put(DiscoveryService.SETTING_DISCOVERY_SEED, random().nextLong())
+                .build()).start();
     }
 
     @AfterClass
@@ -73,6 +86,8 @@ public class TribeUnitTests extends ESTestCase {
         System.setProperty("es.cluster.name", "tribe_node_cluster");
         System.setProperty("es.tribe.t1.cluster.name", "tribe1");
         System.setProperty("es.tribe.t2.cluster.name", "tribe2");
+        System.setProperty("es.tribe.t1.discovery.id.seed", Long.toString(random().nextLong()));
+        System.setProperty("es.tribe.t2.discovery.id.seed", Long.toString(random().nextLong()));
 
         try {
             assertTribeNodeSuccesfullyCreated(Settings.EMPTY);
@@ -80,6 +95,8 @@ public class TribeUnitTests extends ESTestCase {
             System.clearProperty("es.cluster.name");
             System.clearProperty("es.tribe.t1.cluster.name");
             System.clearProperty("es.tribe.t2.cluster.name");
+            System.clearProperty("es.tribe.t1.discovery.id.seed");
+            System.clearProperty("es.tribe.t2.discovery.id.seed");
         }
     }
 

qa/evil-tests/src/test/resources/org/elasticsearch/tribe/elasticsearch.yml

@@ -1,3 +1,5 @@
 cluster.name: tribe_node_cluster
 tribe.t1.cluster.name: tribe1
-tribe.t2.cluster.name: tribe2
+tribe.t2.cluster.name: tribe2
+tribe.t1.discovery.id.seed: 1
+tribe.t2.discovery.id.seed: 2

test-framework/src/main/java/org/elasticsearch/test/ESAllocationTestCase.java

@@ -36,6 +36,7 @@ import org.elasticsearch.cluster.routing.allocation.allocator.ShardsAllocators;
 import org.elasticsearch.cluster.routing.allocation.decider.AllocationDecider;
 import org.elasticsearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.elasticsearch.cluster.routing.allocation.decider.Decision;
+import org.elasticsearch.common.Randomness;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.transport.DummyTransportAddress;
 import org.elasticsearch.common.transport.TransportAddress;
@@ -111,7 +112,7 @@ public abstract class ESAllocationTestCase extends ESTestCase {
         for (AllocationDecider d : list) {
             assertThat(defaultAllocationDeciders.contains(d.getClass()), is(true));
         }
-        Collections.shuffle(list, random);
+        Randomness.shuffle(list);
         return new AllocationDeciders(settings, list.toArray(new AllocationDecider[0]));
 
     }

test-framework/src/main/java/org/elasticsearch/test/ESIntegTestCase.java

@@ -533,7 +533,7 @@ public abstract class ESIntegTestCase extends ESTestCase {
     }
 
     private TestCluster buildWithPrivateContext(final Scope scope, final long seed) throws Exception {
-        return RandomizedContext.current().runWithPrivateRandomness(new Randomness(seed), new Callable<TestCluster>() {
+        return RandomizedContext.current().runWithPrivateRandomness(new com.carrotsearch.randomizedtesting.Randomness(seed), new Callable<TestCluster>() {
             @Override
             public TestCluster call() throws Exception {
                 return buildTestCluster(scope, seed);
@@ -1388,7 +1388,7 @@ public abstract class ESIntegTestCase extends ESTestCase {
             }
         }
         final String[] indices = indicesSet.toArray(new String[indicesSet.size()]);
-        Collections.shuffle(builders, random);
+        Collections.shuffle(builders, random());
         final CopyOnWriteArrayList<Tuple<IndexRequestBuilder, Throwable>> errors = new CopyOnWriteArrayList<>();
         List<CountDownLatch> inFlightAsyncOperations = new ArrayList<>();
         // If you are indexing just a few documents then frequently do it one at a time.  If many then frequently in bulk.

test-framework/src/main/java/org/elasticsearch/test/ESTestCase.java

@@ -566,7 +566,7 @@ public abstract class ESTestCase extends LuceneTestCase {
             throw new IllegalArgumentException("Can\'t pick " + size + " random objects from a list of " + values.length + " objects");
         }
         List<T> list = arrayAsArrayList(values);
-        Collections.shuffle(list);
+        Collections.shuffle(list, random());
         return list.subList(0, size);
     }
 
@@ -615,7 +615,7 @@ public abstract class ESTestCase extends LuceneTestCase {
         sb.append("]");
         assertThat(count + " files exist that should have been cleaned:\n" + sb.toString(), count, equalTo(0));
     }
-    
+
     /** Returns the suite failure marker: internal use only! */
     public static TestRuleMarkFailure getSuiteFailureMarker() {
         return suiteFailureMarker;