HDDS-11544. Improve work with arrays.

hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/security/x509/certificate/utils/CertificateSignRequest.java

@@ -27,13 +27,12 @@
 import java.util.List;
 import java.util.Optional;
 
+import com.google.common.base.Preconditions;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.commons.validator.routines.DomainValidator;
 import org.apache.hadoop.hdds.security.SecurityConfig;
 import org.apache.hadoop.hdds.security.exception.SCMSecurityException;
 import org.apache.hadoop.hdds.security.x509.exception.CertificateException;
-
-import com.google.common.base.Preconditions;
 import org.apache.hadoop.ozone.OzoneSecurityUtil;
 import org.bouncycastle.asn1.ASN1EncodableVector;
 import org.bouncycastle.asn1.ASN1Object;
@@ -390,7 +389,7 @@ private Optional<Extension> getSubjectAltNameExtension() throws
       if (altNames != null) {
         return Optional.of(new Extension(Extension.subjectAlternativeName,
             false, new DEROctetString(new GeneralNames(
-            altNames.toArray(new GeneralName[altNames.size()])))));
+            altNames.toArray(new GeneralName[0])))));
       }
       return Optional.empty();
     }
@@ -414,12 +413,10 @@ private Extensions createExtensions() throws IOException {
 
       // Add subject alternate name extension
       Optional<Extension> san = getSubjectAltNameExtension();
-      if (san.isPresent()) {
-        extensions.add(san.get());
-      }
+      san.ifPresent(extensions::add);
 
       return new Extensions(
-          extensions.toArray(new Extension[extensions.size()]));
+          extensions.toArray(new Extension[0]));
     }
 
     public CertificateSignRequest build() throws SCMSecurityException {

hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/HddsPolicyProvider.java

@@ -24,7 +24,7 @@
 import org.apache.hadoop.security.authorize.Service;
 import org.apache.ratis.util.MemoizedSupplier;
 
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.function.Supplier;
 
@@ -50,7 +50,7 @@ public static HddsPolicyProvider getInstance() {
   }
 
   private static final List<Service> DN_SERVICES =
-      Arrays.asList(
+      Collections.singletonList(
           new Service(
               OZONE_SECURITY_RECONFIGURE_PROTOCOL_ACL,
               ReconfigureProtocol.class)

hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/transport/server/ratis/ContainerStateMachine.java

@@ -41,8 +41,9 @@
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.Consumer;
-import java.util.stream.Collectors;
 
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Preconditions;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
 import org.apache.hadoop.hdds.HddsUtils;
 import org.apache.hadoop.hdds.conf.ConfigurationSource;
@@ -69,21 +70,18 @@
 import org.apache.hadoop.ozone.container.keyvalue.impl.KeyValueStreamDataChannel;
 import org.apache.hadoop.ozone.container.ozoneimpl.ContainerController;
 import org.apache.hadoop.util.Time;
-
-import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Preconditions;
 import org.apache.ratis.proto.RaftProtos;
-import org.apache.ratis.proto.RaftProtos.StateMachineEntryProto;
 import org.apache.ratis.proto.RaftProtos.LogEntryProto;
 import org.apache.ratis.proto.RaftProtos.RaftPeerRole;
 import org.apache.ratis.proto.RaftProtos.RoleInfoProto;
+import org.apache.ratis.proto.RaftProtos.StateMachineEntryProto;
 import org.apache.ratis.proto.RaftProtos.StateMachineLogEntryProto;
 import org.apache.ratis.protocol.Message;
 import org.apache.ratis.protocol.RaftClientRequest;
 import org.apache.ratis.protocol.RaftGroupId;
 import org.apache.ratis.protocol.RaftGroupMemberId;
-import org.apache.ratis.protocol.RaftPeerId;
 import org.apache.ratis.protocol.RaftPeer;
+import org.apache.ratis.protocol.RaftPeerId;
 import org.apache.ratis.protocol.exceptions.StateMachineException;
 import org.apache.ratis.server.RaftServer;
 import org.apache.ratis.server.protocol.TermIndex;
@@ -98,10 +96,10 @@
 import org.apache.ratis.thirdparty.com.google.protobuf.ByteString;
 import org.apache.ratis.thirdparty.com.google.protobuf.InvalidProtocolBufferException;
 import org.apache.ratis.thirdparty.com.google.protobuf.TextFormat;
+import org.apache.ratis.util.JavaUtils;
 import org.apache.ratis.util.LifeCycle;
 import org.apache.ratis.util.TaskQueue;
 import org.apache.ratis.util.function.CheckedSupplier;
-import org.apache.ratis.util.JavaUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -818,11 +816,9 @@ private ByteString readStateMachineData(
    */
   @Override
   public CompletableFuture<Void> flush(long index) {
-    List<CompletableFuture<ContainerCommandResponseProto>> futureList =
-        writeChunkFutureMap.entrySet().stream().filter(x -> x.getKey() <= index)
-            .map(Map.Entry::getValue).collect(Collectors.toList());
     return CompletableFuture.allOf(
-        futureList.toArray(new CompletableFuture[futureList.size()]));
+        writeChunkFutureMap.entrySet().stream().filter(x -> x.getKey() <= index)
+            .map(Map.Entry::getValue).toArray(CompletableFuture[]::new));
   }
 
   /**

hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/ec/reconstruction/ECContainerOperationClient.java

@@ -18,11 +18,13 @@
 package org.apache.hadoop.ozone.container.ec.reconstruction;
 
 import com.google.common.collect.ImmutableList;
+import jakarta.annotation.Nonnull;
 import org.apache.commons.collections.map.SingletonMap;
 import org.apache.hadoop.hdds.client.ECReplicationConfig;
 import org.apache.hadoop.hdds.conf.ConfigurationSource;
 import org.apache.hadoop.hdds.protocol.DatanodeDetails;
 import org.apache.hadoop.hdds.protocol.datanode.proto.ContainerProtos;
+import org.apache.hadoop.hdds.protocol.datanode.proto.ContainerProtos.ContainerDataProto.State;
 import org.apache.hadoop.hdds.scm.XceiverClientManager;
 import org.apache.hadoop.hdds.scm.XceiverClientSpi;
 import org.apache.hadoop.hdds.scm.client.ClientTrustManager;
@@ -34,8 +36,6 @@
 import org.apache.hadoop.ozone.container.common.helpers.BlockData;
 import org.apache.hadoop.security.token.Token;
 import org.apache.hadoop.security.token.TokenIdentifier;
-import org.apache.hadoop.hdds.protocol.datanode.proto.ContainerProtos.ContainerDataProto.State;
-import jakarta.annotation.Nonnull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -44,7 +44,6 @@
 import java.util.List;
 import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 /**
  * This class wraps necessary container-level rpc calls
@@ -93,14 +92,11 @@ public BlockData[] listBlock(long containerId, DatanodeDetails dn,
         try {
           return BlockData.getFromProtoBuf(i);
         } catch (IOException e) {
-          LOG.debug("Failed while converting to protobuf BlockData. Returning"
-                  + " null for listBlock from DN: " + dn,
-              e);
+          LOG.debug("Failed while converting to protobuf BlockData. Returning null for listBlock from DN: {}", dn, e);
           // TODO: revisit here.
           return null;
         }
-      }).collect(Collectors.toList())
-          .toArray(new BlockData[blockDataList.size()]);
+      }).toArray(BlockData[]::new);
     } finally {
       this.xceiverClientManager.releaseClient(xceiverClient, false);
     }

hadoop-hdds/erasurecode/src/main/java/org/apache/ozone/erasurecode/CodecRegistry.java

@@ -19,9 +19,9 @@
 
 import com.google.common.annotations.VisibleForTesting;
 import org.apache.hadoop.hdds.annotation.InterfaceAudience;
-import org.apache.ozone.erasurecode.rawcoder.RawErasureCoderFactory;
 import org.apache.ozone.erasurecode.rawcoder.NativeRSRawErasureCoderFactory;
 import org.apache.ozone.erasurecode.rawcoder.NativeXORRawErasureCoderFactory;
+import org.apache.ozone.erasurecode.rawcoder.RawErasureCoderFactory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -31,7 +31,6 @@
 import java.util.Map;
 import java.util.ServiceLoader;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 /**
  * This class registers all coder implementations.
@@ -108,8 +107,8 @@ void updateCoders(Iterable<RawErasureCoderFactory> coderFactories) {
       String codecName = entry.getKey();
       List<RawErasureCoderFactory> coders = entry.getValue();
       coderNameMap.put(codecName, coders.stream().
-          map(RawErasureCoderFactory::getCoderName).
-          collect(Collectors.toList()).toArray(new String[0]));
+          map(RawErasureCoderFactory::getCoderName)
+          .toArray(String[]::new));
     }
   }
 

hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/utils/DBCheckpointServlet.java

@@ -41,22 +41,20 @@
 import org.apache.commons.fileupload.servlet.ServletFileUpload;
 import org.apache.commons.fileupload.util.Streams;
 import org.apache.commons.io.FileUtils;
+import org.apache.commons.lang3.StringUtils;
 import org.apache.hadoop.hdds.server.OzoneAdmins;
 import org.apache.hadoop.hdds.utils.db.DBCheckpoint;
 import org.apache.hadoop.hdds.utils.db.DBStore;
-
-import org.apache.commons.lang3.StringUtils;
+import org.apache.hadoop.ozone.lock.BootstrapStateHandler;
+import org.apache.hadoop.security.UserGroupInformation;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import static org.apache.hadoop.hdds.utils.HddsServerUtil.writeDBCheckpointToStream;
 import static org.apache.hadoop.ozone.OzoneConsts.OZONE_DB_CHECKPOINT_REQUEST_FLUSH;
 import static org.apache.hadoop.ozone.OzoneConsts.OZONE_DB_CHECKPOINT_REQUEST_TO_EXCLUDE_SST;
 import static org.apache.hadoop.ozone.OzoneConsts.ROCKSDB_SST_SUFFIX;
 
-import org.apache.hadoop.ozone.lock.BootstrapStateHandler;
-import org.apache.hadoop.security.UserGroupInformation;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 /**
  * Provides the current checkpoint Snapshot of the OM/SCM DB. (tar)
  */
@@ -287,7 +285,7 @@ private static String[] parseFormDataParameters(HttpServletRequest request) {
       LOG.warn("Exception occured during form data parsing {}", e.getMessage());
     }
 
-    return sstParam.size() == 0 ? null : sstParam.toArray(new String[0]);
+    return sstParam.isEmpty() ? null : sstParam.toArray(new String[0]);
   }
 
   /**

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/container/balancer/ContainerBalancerTask.java

@@ -691,7 +691,7 @@ private void checkIterationMoveResults() {
         moveSelectionToFutureMap.values();
     if (!futures.isEmpty()) {
       CompletableFuture<Void> allFuturesResult = CompletableFuture.allOf(
-          futures.toArray(new CompletableFuture[futures.size()]));
+          futures.toArray(new CompletableFuture[0]));
       try {
         allFuturesResult.get(config.getMoveTimeout().toMillis(),
             TimeUnit.MILLISECONDS);

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/container/placement/algorithms/SCMContainerPlacementRackAware.java

@@ -346,8 +346,7 @@ protected List<DatanodeDetails> chooseDatanodesInternalLegacy(
       return chooseNodes(null, chosenNodes, mutableFavoredNodes,
           mutableUsedNodes, favorIndex, nodesRequired, mapSizeRequired);
     } else {
-      List<DatanodeDetails> mutableExcludedNodes = new ArrayList<>();
-      mutableExcludedNodes.addAll(excludedNodes);
+      List<DatanodeDetails> mutableExcludedNodes = new ArrayList<>(excludedNodes);
       // choose node to meet replication requirement
       // case 1: one excluded node, choose one on the same rack as the excluded
       // node, choose others on different racks.

hadoop-hdds/server-scm/src/test/java/org/apache/hadoop/hdds/scm/block/TestBlockManager.java

@@ -22,15 +22,15 @@
 import java.time.Clock;
 import java.time.ZoneId;
 import java.time.ZoneOffset;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
-import java.util.ArrayList;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.ExecutorService;
 
 import org.apache.hadoop.hdds.HddsConfigKeys;
 import org.apache.hadoop.hdds.client.RatisReplicationConfig;
@@ -39,30 +39,30 @@
 import org.apache.hadoop.hdds.protocol.proto.HddsProtos;
 import org.apache.hadoop.hdds.protocol.proto.HddsProtos.ReplicationFactor;
 import org.apache.hadoop.hdds.protocol.proto.StorageContainerDatanodeProtocolProtos.SCMCommandProto;
-import org.apache.hadoop.hdds.scm.ScmConfigKeys;
 import org.apache.hadoop.hdds.scm.HddsTestUtils;
-import org.apache.hadoop.hdds.scm.container.replication.ContainerReplicaPendingOps;
-import org.apache.hadoop.hdds.scm.ha.SCMHAManagerStub;
-import org.apache.hadoop.hdds.scm.ha.SequenceIdGenerator;
-import org.apache.hadoop.hdds.scm.ha.SCMServiceManager;
-import org.apache.hadoop.hdds.scm.ha.SCMContext;
-import org.apache.hadoop.hdds.scm.ha.SCMHAManager;
-import org.apache.hadoop.hdds.scm.node.NodeStatus;
+import org.apache.hadoop.hdds.scm.ScmConfigKeys;
 import org.apache.hadoop.hdds.scm.container.CloseContainerEventHandler;
 import org.apache.hadoop.hdds.scm.container.ContainerID;
-import org.apache.hadoop.hdds.scm.container.ContainerManagerImpl;
 import org.apache.hadoop.hdds.scm.container.ContainerManager;
+import org.apache.hadoop.hdds.scm.container.ContainerManagerImpl;
 import org.apache.hadoop.hdds.scm.container.MockNodeManager;
 import org.apache.hadoop.hdds.scm.container.common.helpers.AllocatedBlock;
 import org.apache.hadoop.hdds.scm.container.common.helpers.ExcludeList;
+import org.apache.hadoop.hdds.scm.container.replication.ContainerReplicaPendingOps;
 import org.apache.hadoop.hdds.scm.events.SCMEvents;
+import org.apache.hadoop.hdds.scm.ha.SCMContext;
+import org.apache.hadoop.hdds.scm.ha.SCMHAManager;
+import org.apache.hadoop.hdds.scm.ha.SCMHAManagerStub;
+import org.apache.hadoop.hdds.scm.ha.SCMServiceManager;
+import org.apache.hadoop.hdds.scm.ha.SequenceIdGenerator;
 import org.apache.hadoop.hdds.scm.metadata.SCMMetadataStore;
 import org.apache.hadoop.hdds.scm.metadata.SCMMetadataStoreImpl;
+import org.apache.hadoop.hdds.scm.node.NodeStatus;
 import org.apache.hadoop.hdds.scm.pipeline.MockRatisPipelineProvider;
 import org.apache.hadoop.hdds.scm.pipeline.Pipeline;
 import org.apache.hadoop.hdds.scm.pipeline.PipelineID;
-import org.apache.hadoop.hdds.scm.pipeline.PipelineProvider;
 import org.apache.hadoop.hdds.scm.pipeline.PipelineManagerImpl;
+import org.apache.hadoop.hdds.scm.pipeline.PipelineProvider;
 import org.apache.hadoop.hdds.scm.safemode.SCMSafeModeManager;
 import org.apache.hadoop.hdds.scm.safemode.SCMSafeModeManager.SafeModeStatus;
 import org.apache.hadoop.hdds.scm.server.SCMConfigurator;
@@ -76,21 +76,19 @@
 import org.apache.hadoop.ozone.protocol.commands.CommandForDatanode;
 import org.apache.hadoop.ozone.protocol.commands.CreatePipelineCommand;
 import org.apache.ozone.test.GenericTestUtils;
-
-import static org.apache.hadoop.ozone.OzoneConsts.GB;
-import static org.apache.hadoop.ozone.OzoneConsts.MB;
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotEquals;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.Timeout;
 import org.junit.jupiter.api.io.TempDir;
 
+import static org.apache.hadoop.ozone.OzoneConsts.GB;
+import static org.apache.hadoop.ozone.OzoneConsts.MB;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
  * Tests for SCM Block Manager.
@@ -273,7 +271,7 @@ void testAllocateBlockInParallel() throws Exception {
     }
 
     CompletableFuture
-        .allOf(futureList.toArray(new CompletableFuture[futureList.size()]))
+        .allOf(futureList.toArray(new CompletableFuture[0]))
         .get();
   }
 

hadoop-hdds/server-scm/src/test/java/org/apache/hadoop/hdds/scm/block/TestDeletedBlockLog.java

@@ -265,7 +265,7 @@ private void commitTransactions(
       List<DeleteBlockTransactionResult> transactionResults)
       throws IOException {
     commitTransactions(transactionResults,
-        dnList.toArray(new DatanodeDetails[3]));
+        dnList.toArray(new DatanodeDetails[0]));
   }
 
   private void commitTransactions(

hadoop-hdds/server-scm/src/test/java/org/apache/hadoop/hdds/scm/container/TestIncrementalContainerReportHandler.java

@@ -644,7 +644,7 @@ public void testECReplicaIndexValidation() throws NodeNotFoundException,
           IOException, TimeoutException {
     List<DatanodeDetails> dns = IntStream.range(0, 5)
         .mapToObj(i -> randomDatanodeDetails()).collect(Collectors.toList());
-    dns.stream().forEach(dn -> nodeManager.register(dn, null, null));
+    dns.forEach(dn -> nodeManager.register(dn, null, null));
     ECReplicationConfig replicationConfig = new ECReplicationConfig(3, 2);
     final ContainerInfo container = getECContainer(LifeCycleState.CLOSED,
             PipelineID.randomId(), replicationConfig);

hadoop-ozone/client/src/test/java/org/apache/hadoop/ozone/client/TestOzoneECClient.java

@@ -153,7 +153,7 @@ public void testPutECKeyAndCheckDNStoredData() throws IOException {
     Map<DatanodeDetails, MockDatanodeStorage> storages =
         factoryStub.getStorages();
     DatanodeDetails[] dnDetails =
-        storages.keySet().toArray(new DatanodeDetails[storages.size()]);
+        storages.keySet().toArray(new DatanodeDetails[0]);
     Arrays.sort(dnDetails);
     for (int i = 0; i < inputChunks.length; i++) {
       MockDatanodeStorage datanodeStorage = storages.get(dnDetails[i]);
@@ -182,7 +182,7 @@ public void testPutECKeyAndCheckParityData() throws IOException {
     Map<DatanodeDetails, MockDatanodeStorage> storages =
         factoryStub.getStorages();
     DatanodeDetails[] dnDetails =
-        storages.keySet().toArray(new DatanodeDetails[storages.size()]);
+        storages.keySet().toArray(new DatanodeDetails[0]);
     Arrays.sort(dnDetails);
 
     for (int i = dataBlocks; i < parityBlocks + dataBlocks; i++) {