Simplified condition (#273)

Signed-off-by: Rahil <rahilrshk@gmail.com>

src/main/java/org/tikv/cdc/CDCEvent.java

@@ -1,14 +1,13 @@
 package org.tikv.cdc;
 
-import java.util.Objects;
 import org.tikv.kvproto.Cdcpb.Event.Row;
 
 class CDCEvent {
   enum CDCEventType {
     ROW,
     RESOLVED_TS,
-    ERROR;
-  };
+    ERROR
+  }
 
   public final long regionId;
 
@@ -57,7 +56,7 @@ class CDCEvent {
         builder.append("resolvedTs=").append(resolvedTs);
         break;
       case ROW:
-        builder.append("row=").append(Objects.toString(row));
+        builder.append("row=").append(row);
         break;
     }
     return builder.append("}").toString();

src/main/java/org/tikv/cdc/RegionCDCClient.java

@@ -42,7 +42,7 @@ class RegionCDCClient implements AutoCloseable, StreamObserver<ChangeDataEvent>
 
   private final AtomicBoolean running = new AtomicBoolean(false);
 
-  private boolean started = false;
+  private final boolean started = false;
 
   public RegionCDCClient(
       final TiRegion region,

src/main/java/org/tikv/common/MetricsServer.java

@@ -30,9 +30,8 @@ public class MetricsServer {
   private static MetricsServer METRICS_SERVER_INSTANCE = null;
   private static int metricsServerRefCount = 0;
 
-  private int port;
-  private HTTPServer server;
-  private CollectorRegistry collectorRegistry;
+  private final int port;
+  private final HTTPServer server;
 
   public static MetricsServer getInstance(TiConfiguration conf) {
     if (!conf.isMetricsEnable()) {
@@ -58,16 +57,16 @@ public class MetricsServer {
 
   private MetricsServer(int port) {
     try {
-      this.collectorRegistry = new CollectorRegistry();
-      this.collectorRegistry.register(RawKVClient.RAW_REQUEST_LATENCY);
-      this.collectorRegistry.register(RawKVClient.RAW_REQUEST_FAILURE);
-      this.collectorRegistry.register(RawKVClient.RAW_REQUEST_SUCCESS);
-      this.collectorRegistry.register(RegionStoreClient.GRPC_RAW_REQUEST_LATENCY);
-      this.collectorRegistry.register(RetryPolicy.GRPC_SINGLE_REQUEST_LATENCY);
-      this.collectorRegistry.register(RegionManager.GET_REGION_BY_KEY_REQUEST_LATENCY);
-      this.collectorRegistry.register(PDClient.PD_GET_REGION_BY_KEY_REQUEST_LATENCY);
+      CollectorRegistry collectorRegistry = new CollectorRegistry();
+      collectorRegistry.register(RawKVClient.RAW_REQUEST_LATENCY);
+      collectorRegistry.register(RawKVClient.RAW_REQUEST_FAILURE);
+      collectorRegistry.register(RawKVClient.RAW_REQUEST_SUCCESS);
+      collectorRegistry.register(RegionStoreClient.GRPC_RAW_REQUEST_LATENCY);
+      collectorRegistry.register(RetryPolicy.GRPC_SINGLE_REQUEST_LATENCY);
+      collectorRegistry.register(RegionManager.GET_REGION_BY_KEY_REQUEST_LATENCY);
+      collectorRegistry.register(PDClient.PD_GET_REGION_BY_KEY_REQUEST_LATENCY);
       this.port = port;
-      this.server = new HTTPServer(new InetSocketAddress(port), this.collectorRegistry, true);
+      this.server = new HTTPServer(new InetSocketAddress(port), collectorRegistry, true);
       logger.info("http server is up " + this.server.getPort());
     } catch (Exception e) {
       logger.error("http server not up");

src/main/java/org/tikv/common/PDClient.java

@@ -188,7 +188,7 @@ public class PDClient extends AbstractGRPCClient<PDBlockingStub, PDStub>
                   "wait scatter region %d at key %s is %s",
                   region.getId(),
                   KeyUtils.formatBytes(resp.getDesc().toByteArray()),
-                  resp.getStatus().toString()));
+                  resp.getStatus()));
         }
       }
     }
@@ -422,11 +422,9 @@ public class PDClient extends AbstractGRPCClient<PDBlockingStub, PDStub>
       logger.info(String.format("can not switch to new leader, try follower forward"));
       List<Pdpb.Member> members = resp.getMembersList();
 
-      boolean hasReachNextMember = false;
       // If we have not used follower forward, try the first follower.
-      if (pdClientWrapper != null && pdClientWrapper.getStoreAddress().equals(leaderUrlStr)) {
-        hasReachNextMember = true;
-      }
+      boolean hasReachNextMember =
+          pdClientWrapper != null && pdClientWrapper.getStoreAddress().equals(leaderUrlStr);
 
       for (int i = 0; i < members.size() * 2; i++) {
         Pdpb.Member member = members.get(i % members.size());

src/main/java/org/tikv/common/TiConfiguration.java

@@ -266,7 +266,7 @@ public class TiConfiguration implements Serializable {
   private boolean showRowId = getBoolean(TIKV_SHOW_ROWID);
   private String dbPrefix = get(TIKV_DB_PREFIX);
   private KVMode kvMode = getKvMode(TIKV_KV_MODE);
-  private boolean enableGrpcForward = getBoolean(TIKV_ENABLE_GRPC_FORWARD);
+  private final boolean enableGrpcForward = getBoolean(TIKV_ENABLE_GRPC_FORWARD);
 
   private int kvClientConcurrency = getInt(TIKV_KV_CLIENT_CONCURRENCY);
   private ReplicaRead replicaRead = getReplicaRead(TIKV_REPLICA_READ);
@@ -275,8 +275,8 @@ public class TiConfiguration implements Serializable {
 
   private boolean metricsEnable = getBoolean(TIKV_METRICS_ENABLE);
   private int metricsPort = getInt(TIKV_METRICS_PORT);
-  private int grpcHealthCheckTimeout = getInt(TIKV_GRPC_HEALTH_CHECK_TIMEOUT);
-  private int healthCheckPeriodDuration = getInt(TIKV_HEALTH_CHECK_PERIOD_DURATION);
+  private final int grpcHealthCheckTimeout = getInt(TIKV_GRPC_HEALTH_CHECK_TIMEOUT);
+  private final int healthCheckPeriodDuration = getInt(TIKV_HEALTH_CHECK_PERIOD_DURATION);
 
   private final String networkMappingName = get(TIKV_NETWORK_MAPPING_NAME);
   private HostMapping hostMapping = null;

src/main/java/org/tikv/common/TiSession.java

@@ -73,7 +73,7 @@ public class TiSession implements AutoCloseable {
   private volatile ImporterStoreClient.ImporterStoreClientBuilder importerClientBuilder;
   private volatile boolean isClosed = false;
   private volatile SwitchTiKVModeClient switchTiKVModeClient;
-  private MetricsServer metricsServer;
+  private final MetricsServer metricsServer;
   private static final int MAX_SPLIT_REGION_STACK_DEPTH = 6;
 
   public TiSession(TiConfiguration conf) {

src/main/java/org/tikv/common/expression/RangeColumnPartitionPruner.java

@@ -79,7 +79,7 @@ public class RangeColumnPartitionPruner
     NormalizedPredicate predicate = node.normalize();
     if (predicate == null) {
       throw new UnsupportedOperationException(
-          String.format("ComparisonBinaryExpression %s cannot be normalized", node.toString()));
+          String.format("ComparisonBinaryExpression %s cannot be normalized", node));
     }
     String colRefName = predicate.getColumnRef().getName();
     List<Expression> partExprs = partExprsPerColumnRef.get(colRefName);

src/main/java/org/tikv/common/parser/AstBuilder.java

@@ -117,7 +117,7 @@ public class AstBuilder extends MySqlParserBaseVisitor<Expression> {
       return parseIntOrLongOrDec(val);
     }
 
-    throw new UnsupportedSyntaxException(ctx.toString() + ": it is not supported.");
+    throw new UnsupportedSyntaxException(ctx + ": it is not supported.");
   }
 
   @Override
@@ -135,7 +135,7 @@ public class AstBuilder extends MySqlParserBaseVisitor<Expression> {
       }
       return Constant.create(sb.toString().replace("\"", ""));
     }
-    throw new UnsupportedSyntaxException(ctx.toString() + " is not supported yet");
+    throw new UnsupportedSyntaxException(ctx + " is not supported yet");
   }
 
   @Override
@@ -161,7 +161,7 @@ public class AstBuilder extends MySqlParserBaseVisitor<Expression> {
           Doubles.tryParse(ctx.REAL_LITERAL().getSymbol().getText()), RealType.REAL);
     }
 
-    throw new UnsupportedSyntaxException(ctx.toString() + "not supported constant");
+    throw new UnsupportedSyntaxException(ctx + "not supported constant");
   }
 
   @Override
@@ -187,8 +187,7 @@ public class AstBuilder extends MySqlParserBaseVisitor<Expression> {
         return ComparisonBinaryExpression.greaterEqual(left, right);
     }
 
-    throw new UnsupportedSyntaxException(
-        ctx.toString() + ": it is not possible reach to this line of code");
+    throw new UnsupportedSyntaxException(ctx + ": it is not possible reach to this line of code");
   }
 
   public Expression visitLogicalExpression(MySqlParser.LogicalExpressionContext ctx) {
@@ -203,8 +202,7 @@ public class AstBuilder extends MySqlParserBaseVisitor<Expression> {
         return LogicalBinaryExpression.xor(visitChildren(left), visitChildren(right));
     }
 
-    throw new UnsupportedSyntaxException(
-        ctx.toString() + ": it is not possible reach to this line of code");
+    throw new UnsupportedSyntaxException(ctx + ": it is not possible reach to this line of code");
   }
 
   @Override
@@ -222,6 +220,6 @@ public class AstBuilder extends MySqlParserBaseVisitor<Expression> {
       case "div":
         return ArithmeticBinaryExpression.divide(left, right);
     }
-    throw new UnsupportedSyntaxException(ctx.toString() + ": it is not supported right now");
+    throw new UnsupportedSyntaxException(ctx + ": it is not supported right now");
   }
 }

src/main/java/org/tikv/common/policy/RetryPolicy.java

@@ -41,9 +41,9 @@ public abstract class RetryPolicy<RespT> {
           .register();
 
   // handles PD and TiKV's error.
-  private ErrorHandler<RespT> handler;
+  private final ErrorHandler<RespT> handler;
 
-  private ImmutableSet<Status.Code> unrecoverableStatus =
+  private final ImmutableSet<Status.Code> unrecoverableStatus =
       ImmutableSet.of(
           Status.Code.ALREADY_EXISTS, Status.Code.PERMISSION_DENIED,
           Status.Code.INVALID_ARGUMENT, Status.Code.NOT_FOUND,

src/main/java/org/tikv/common/region/RegionManager.java

@@ -151,7 +151,7 @@ public class RegionManager {
       ByteString key, TiStoreType storeType, BackOffer backOffer) {
     TiRegion region = getRegionByKey(key, backOffer);
     if (!region.isValid()) {
-      throw new TiClientInternalException("Region invalid: " + region.toString());
+      throw new TiClientInternalException("Region invalid: " + region);
     }
 
     TiStore store = null;
@@ -181,7 +181,7 @@ public class RegionManager {
 
     if (store == null) {
       throw new TiClientInternalException(
-          "Cannot find valid store on " + storeType + " for region " + region.toString());
+          "Cannot find valid store on " + storeType + " for region " + region);
     }
 
     return Pair.create(region, store);

src/main/java/org/tikv/common/region/StoreHealthyChecker.java

@@ -19,12 +19,12 @@ import org.tikv.kvproto.Metapb;
 public class StoreHealthyChecker implements Runnable {
   private static final Logger logger = LoggerFactory.getLogger(StoreHealthyChecker.class);
   private static final long MAX_CHECK_STORE_TOMBSTONE_TICK = 60;
-  private BlockingQueue<TiStore> taskQueue;
+  private final BlockingQueue<TiStore> taskQueue;
   private final ChannelFactory channelFactory;
   private final ReadOnlyPDClient pdClient;
   private final RegionCache cache;
   private long checkTombstoneTick;
-  private long timeout;
+  private final long timeout;
 
   public StoreHealthyChecker(
       ChannelFactory channelFactory, ReadOnlyPDClient pdClient, RegionCache cache, long timeout) {
@@ -37,11 +37,8 @@ public class StoreHealthyChecker implements Runnable {
   }
 
   public boolean scheduleStoreHealthCheck(TiStore store) {
-    if (!this.taskQueue.add(store)) {
-      // add queue false, mark it reachable so that it can be put again.
-      return false;
-    }
-    return true;
+    // add queue false, mark it reachable so that it can be put again.
+    return this.taskQueue.add(store);
   }
 
   private List<TiStore> getValidStores() {
@@ -68,11 +65,7 @@ public class StoreHealthyChecker implements Runnable {
           HealthGrpc.newBlockingStub(channel).withDeadlineAfter(timeout, TimeUnit.MILLISECONDS);
       HealthCheckRequest req = HealthCheckRequest.newBuilder().build();
       HealthCheckResponse resp = stub.check(req);
-      if (resp.getStatus() == HealthCheckResponse.ServingStatus.SERVING) {
-        return true;
-      } else {
-        return false;
-      }
+      return resp.getStatus() == HealthCheckResponse.ServingStatus.SERVING;
     } catch (Exception e) {
       return false;
     }

src/main/java/org/tikv/common/region/TiStore.java

@@ -6,13 +6,13 @@ import java.util.concurrent.atomic.AtomicLong;
 import org.tikv.kvproto.Metapb;
 
 public class TiStore implements Serializable {
-  private static long MAX_FAIL_FORWARD_TIMES = 4;
+  private static final long MAX_FAIL_FORWARD_TIMES = 4;
   private final Metapb.Store store;
   private final Metapb.Store proxyStore;
-  private AtomicBoolean reachable;
-  private AtomicBoolean valid;
-  private AtomicLong failForwardCount;
-  private AtomicBoolean canForward;
+  private final AtomicBoolean reachable;
+  private final AtomicBoolean valid;
+  private final AtomicLong failForwardCount;
+  private final AtomicBoolean canForward;
 
   public TiStore(Metapb.Store store) {
     this.store = store;

src/main/java/org/tikv/common/streaming/StreamingResponse.java

@@ -25,8 +25,8 @@ import org.tikv.kvproto.Coprocessor;
 import org.tikv.kvproto.Errorpb;
 
 public class StreamingResponse implements Iterable {
-  private Iterator<Coprocessor.Response> resultIterator;
-  private List<Coprocessor.Response> responseList;
+  private final Iterator<Coprocessor.Response> resultIterator;
+  private final List<Coprocessor.Response> responseList;
 
   @SuppressWarnings("unchecked")
   public StreamingResponse(Iterator resultIterator) {

src/main/java/org/tikv/raw/RawKVClient.java

@@ -1097,9 +1097,9 @@ public class RawKVClient implements AutoCloseable {
 
     private Iterator<KvPair> iterator;
 
-    private ByteString startKey;
-    private ByteString endKey;
-    private boolean keyOnly;
+    private final ByteString startKey;
+    private final ByteString endKey;
+    private final boolean keyOnly;
 
     private KvPair last;
 

src/main/java/org/tikv/txn/LockResolverClientV4.java

@@ -244,7 +244,7 @@ public class LockResolverClientV4 extends AbstractRegionStoreClient
         logger.warn(
             String.format(
                 "lock txn not found, lock has expired, CallerStartTs=%d lock str=%s",
-                callerStartTS, lock.toString()));
+                callerStartTS, lock));
         if (lock.getLockType() == Kvrpcpb.Op.PessimisticLock) {
           return new TxnStatus();
         }

src/test/java/org/tikv/common/PDClientTest.java

@@ -15,11 +15,18 @@
 
 package org.tikv.common;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 import static org.tikv.common.GrpcUtils.encodeKey;
 
 import com.google.protobuf.ByteString;
-import java.util.concurrent.*;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 import org.junit.Test;
 import org.tikv.common.exception.GrpcException;
 import org.tikv.common.meta.TiTimestamp;
@@ -31,31 +38,33 @@ import org.tikv.kvproto.Metapb.Store;
 import org.tikv.kvproto.Metapb.StoreState;
 
 public class PDClientTest extends PDMockServerTest {
+
   private static final String LOCAL_ADDR_IPV6 = "[::]";
+  public static final String HTTP = "http://";
 
   @Test
   public void testCreate() throws Exception {
     try (PDClient client = session.getPDClient()) {
-      assertEquals(client.getPdClientWrapper().getLeaderInfo(), LOCAL_ADDR + ":" + pdServer.port);
-      assertEquals(client.getHeader().getClusterId(), CLUSTER_ID);
+      assertEquals(LOCAL_ADDR + ":" + pdServer.port, client.getPdClientWrapper().getLeaderInfo());
+      assertEquals(CLUSTER_ID, client.getHeader().getClusterId());
     }
   }
 
   @Test
   public void testSwitchLeader() throws Exception {
     try (PDClient client = session.getPDClient()) {
-      client.trySwitchLeader("http://" + LOCAL_ADDR + ":" + (pdServer.port + 1));
+      client.trySwitchLeader(HTTP + LOCAL_ADDR + ":" + (pdServer.port + 1));
       assertEquals(
           client.getPdClientWrapper().getLeaderInfo(),
-          "http://" + LOCAL_ADDR + ":" + (pdServer.port + 1));
+          HTTP + LOCAL_ADDR + ":" + (pdServer.port + 1));
     }
     tearDown();
     setUp(LOCAL_ADDR_IPV6);
     try (PDClient client = session.getPDClient()) {
-      client.trySwitchLeader("http://" + LOCAL_ADDR_IPV6 + ":" + (pdServer.port + 2));
+      client.trySwitchLeader(HTTP + LOCAL_ADDR_IPV6 + ":" + (pdServer.port + 2));
       assertEquals(
           client.getPdClientWrapper().getLeaderInfo(),
-          "http://" + LOCAL_ADDR_IPV6 + ":" + (pdServer.port + 2));
+          HTTP + LOCAL_ADDR_IPV6 + ":" + (pdServer.port + 2));
     }
   }
 
@@ -93,8 +102,8 @@ public class PDClientTest extends PDMockServerTest {
       assertEquals(r.getEndKey(), ByteString.copyFrom(endKey));
       assertEquals(r.getRegionEpoch().getConfVer(), confVer);
       assertEquals(r.getRegionEpoch().getVersion(), ver);
-      assertEquals(l.getId(), 1);
-      assertEquals(l.getStoreId(), 10);
+      assertEquals(1, l.getId());
+      assertEquals(10, l.getStoreId());
     }
   }
 
@@ -119,12 +128,12 @@ public class PDClientTest extends PDMockServerTest {
       Pair<Metapb.Region, Metapb.Peer> rl = client.getRegionByID(defaultBackOff(), 0);
       Metapb.Region r = rl.first;
       Metapb.Peer l = rl.second;
-      assertEquals(r.getStartKey(), ByteString.copyFrom(startKey));
-      assertEquals(r.getEndKey(), ByteString.copyFrom(endKey));
-      assertEquals(r.getRegionEpoch().getConfVer(), confVer);
-      assertEquals(r.getRegionEpoch().getVersion(), ver);
-      assertEquals(l.getId(), 1);
-      assertEquals(l.getStoreId(), 10);
+      assertEquals(ByteString.copyFrom(startKey), r.getStartKey());
+      assertEquals(ByteString.copyFrom(endKey), r.getEndKey());
+      assertEquals(confVer, r.getRegionEpoch().getConfVer());
+      assertEquals(ver, r.getRegionEpoch().getVersion());
+      assertEquals(1, l.getId());
+      assertEquals(10, l.getStoreId());
     }
   }
 
@@ -142,20 +151,20 @@ public class PDClientTest extends PDMockServerTest {
                 GrpcUtils.makeStoreLabel("k1", "v1"),
                 GrpcUtils.makeStoreLabel("k2", "v2"))));
     try (PDClient client = session.getPDClient()) {
-      Store r = client.getStore(defaultBackOff(), 0);
-      assertEquals(r.getId(), storeId);
-      assertEquals(r.getAddress(), testAddress);
-      assertEquals(r.getState(), Metapb.StoreState.Up);
-      assertEquals(r.getLabels(0).getKey(), "k1");
-      assertEquals(r.getLabels(1).getKey(), "k2");
-      assertEquals(r.getLabels(0).getValue(), "v1");
-      assertEquals(r.getLabels(1).getValue(), "v2");
+      Store r = client.getStore(defaultBackOff(), storeId);
+      assertEquals(storeId, r.getId());
+      assertEquals(testAddress, r.getAddress());
+      assertEquals(Metapb.StoreState.Up, r.getState());
+      assertEquals("k1", r.getLabels(0).getKey());
+      assertEquals("k2", r.getLabels(1).getKey());
+      assertEquals("v1", r.getLabels(0).getValue());
+      assertEquals("v2", r.getLabels(1).getValue());
 
       pdServer.addGetStoreResp(
           GrpcUtils.makeGetStoreResponse(
               pdServer.getClusterId(),
               GrpcUtils.makeStore(storeId, testAddress, Metapb.StoreState.Tombstone)));
-      assertEquals(StoreState.Tombstone, client.getStore(defaultBackOff(), 0).getState());
+      assertEquals(StoreState.Tombstone, client.getStore(defaultBackOff(), storeId).getState());
     }
   }
 

src/test/java/org/tikv/common/RegionManagerTest.java

@@ -15,7 +15,9 @@
 
 package org.tikv.common;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.fail;
 
 import com.google.common.collect.RangeMap;
 import com.google.common.collect.TreeRangeMap;
@@ -53,7 +55,7 @@ public class RegionManagerTest extends PDMockServerTest {
   }
 
   @Test
-  public void getRegionByKey() throws Exception {
+  public void getRegionByKey() {
     ByteString startKey = ByteString.copyFrom(new byte[] {1});
     ByteString endKey = ByteString.copyFrom(new byte[] {10});
     ByteString searchKey = ByteString.copyFrom(new byte[] {5});
@@ -96,7 +98,7 @@ public class RegionManagerTest extends PDMockServerTest {
   }
 
   @Test
-  public void getStoreByKey() throws Exception {
+  public void getStoreByKey() {
     ByteString startKey = ByteString.copyFrom(new byte[] {1});
     ByteString endKey = ByteString.copyFrom(new byte[] {10});
     ByteString searchKey = ByteString.copyFrom(new byte[] {5});
@@ -133,7 +135,7 @@ public class RegionManagerTest extends PDMockServerTest {
   }
 
   @Test
-  public void getStoreById() throws Exception {
+  public void getStoreById() {
     long storeId = 234;
     String testAddress = "testAddress";
     pdServer.addGetStoreResp(

src/test/java/org/tikv/common/RegionStoreClientTest.java

@@ -15,7 +15,9 @@
 
 package org.tikv.common;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 import com.google.common.collect.ImmutableList;
 import com.google.protobuf.ByteString;
@@ -62,11 +64,11 @@ public class RegionStoreClientTest extends MockServerTest {
   }
 
   @Test
-  public void rawGetTest() throws Exception {
+  public void rawGetTest() {
     doRawGetTest(createClientV3());
   }
 
-  public void doRawGetTest(RegionStoreClient client) throws Exception {
+  public void doRawGetTest(RegionStoreClient client) {
     server.put("key1", "value1");
     Optional<ByteString> value = client.rawGet(defaultBackOff(), ByteString.copyFromUtf8("key1"));
     assertEquals(ByteString.copyFromUtf8("value1"), value.get());
@@ -93,7 +95,7 @@ public class RegionStoreClientTest extends MockServerTest {
     doGetTest(createClientV3());
   }
 
-  public void doGetTest(RegionStoreClient client) throws Exception {
+  public void doGetTest(RegionStoreClient client) {
     server.put("key1", "value1");
     ByteString value = client.get(defaultBackOff(), ByteString.copyFromUtf8("key1"), 1);
     assertEquals(ByteString.copyFromUtf8("value1"), value);
@@ -110,11 +112,11 @@ public class RegionStoreClientTest extends MockServerTest {
   }
 
   @Test
-  public void batchGetTest() throws Exception {
+  public void batchGetTest() {
     doBatchGetTest(createClientV3());
   }
 
-  public void doBatchGetTest(RegionStoreClient client) throws Exception {
+  public void doBatchGetTest(RegionStoreClient client) {
     server.put("key1", "value1");
     server.put("key2", "value2");
     server.put("key4", "value4");
@@ -145,11 +147,11 @@ public class RegionStoreClientTest extends MockServerTest {
   }
 
   @Test
-  public void scanTest() throws Exception {
+  public void scanTest() {
     doScanTest(createClientV3());
   }
 
-  public void doScanTest(RegionStoreClient client) throws Exception {
+  public void doScanTest(RegionStoreClient client) {
     server.put("key1", "value1");
     server.put("key2", "value2");
     server.put("key4", "value4");

src/test/java/org/tikv/common/codec/CodecTest.java

@@ -23,7 +23,7 @@ import org.tikv.common.codec.Codec.*;
 
 public class CodecTest {
   @Test
-  public void readNWriteLongTest() throws Exception {
+  public void readNWriteLongTest() {
     CodecDataOutput cdo = new CodecDataOutput();
     IntegerCodec.writeLongFully(cdo, 9999L, true);
     IntegerCodec.writeLongFully(cdo, -2333L, false);
@@ -62,7 +62,7 @@ public class CodecTest {
   }
 
   @Test
-  public void readNWriteUnsignedLongTest() throws Exception {
+  public void readNWriteUnsignedLongTest() {
     CodecDataOutput cdo = new CodecDataOutput();
     IntegerCodec.writeULongFully(cdo, 0xffffffffffffffffL, true);
     IntegerCodec.writeULongFully(cdo, Long.MIN_VALUE, false);
@@ -156,7 +156,7 @@ public class CodecTest {
   }
 
   @Test
-  public void writeBytesTest() throws Exception {
+  public void writeBytesTest() {
     CodecDataOutput cdo = new CodecDataOutput();
     Codec.BytesCodec.writeBytes(cdo, "abcdefghijk".getBytes());
     byte[] result = cdo.toBytes();

src/test/java/org/tikv/common/codec/MyDecimalTest.java

@@ -57,17 +57,17 @@ public class MyDecimalTest {
 
   @Test
   public void readWordTest() {
-    assertEquals(MyDecimal.readWord(new int[] {250}, 1, 0), -6);
-    assertEquals(MyDecimal.readWord(new int[] {50}, 1, 0), 50);
+    assertEquals(-6, MyDecimal.readWord(new int[] {250}, 1, 0));
+    assertEquals(50, MyDecimal.readWord(new int[] {50}, 1, 0));
 
-    assertEquals(MyDecimal.readWord(new int[] {250, 250}, 2, 0), -1286);
-    assertEquals(MyDecimal.readWord(new int[] {50, 50}, 2, 0), 12850);
+    assertEquals(-1286, MyDecimal.readWord(new int[] {250, 250}, 2, 0));
+    assertEquals(12850, MyDecimal.readWord(new int[] {50, 50}, 2, 0));
 
-    assertEquals(MyDecimal.readWord(new int[] {250, 250, 250}, 3, 0), -328966);
-    assertEquals(MyDecimal.readWord(new int[] {50, 50, 50}, 3, 0), 3289650);
+    assertEquals(-328966, MyDecimal.readWord(new int[] {250, 250, 250}, 3, 0));
+    assertEquals(3289650, MyDecimal.readWord(new int[] {50, 50, 50}, 3, 0));
 
-    assertEquals(MyDecimal.readWord(new int[] {250, 250, 250, 250}, 4, 0), -84215046);
-    assertEquals(MyDecimal.readWord(new int[] {50, 50, 50, 50}, 4, 0), 842150450);
+    assertEquals(-84215046, MyDecimal.readWord(new int[] {250, 250, 250, 250}, 4, 0));
+    assertEquals(842150450, MyDecimal.readWord(new int[] {50, 50, 50, 50}, 4, 0));
   }
 
   @Test
@@ -113,11 +113,6 @@ public class MyDecimalTest {
     int precision;
     int frac;
 
-    MyDecimalTestStruct(String in, String out) {
-      this.in = in;
-      this.out = out;
-    }
-
     MyDecimalTestStruct(String in, String out, int precision, int frac) {
       this.in = in;
       this.out = out;

src/test/java/org/tikv/common/importer/SwitchTiKVModeTest.java

@@ -24,7 +24,7 @@ public class SwitchTiKVModeTest {
   }
 
   @Test
-  public void swithTiKVModeTest() throws InterruptedException {
+  public void switchTiKVModeTest() throws InterruptedException {
     SwitchTiKVModeClient switchTiKVModeClient = session.getSwitchTiKVModeClient();
     switchTiKVModeClient.keepTiKVToImportMode();
     Thread.sleep(6000);

src/test/java/org/tikv/common/importer/TxnKVIngestTest.java

@@ -38,7 +38,7 @@ public class TxnKVIngestTest {
   }
 
   @Ignore
-  public void txnIngestTest() throws InterruptedException {
+  public void txnIngestTest() {
     KVClient client = session.createKVClient();
 
     // gen test data

src/test/java/org/tikv/common/key/KeyTest.java

@@ -24,7 +24,7 @@ import org.junit.Test;
 public class KeyTest {
 
   @Test
-  public void nextPrefixTest() throws Exception {
+  public void nextPrefixTest() {
     Key k1 = toRawKey(new byte[] {1, 2, 3});
     assertEquals(toRawKey(new byte[] {1, 2, 4}), k1.nextPrefix());
 

src/test/java/org/tikv/raw/MetricsTest.java

@@ -13,7 +13,7 @@ import org.tikv.common.TiConfiguration;
 import org.tikv.common.TiSession;
 
 public class MetricsTest {
-  private List<TiSession> sessionList = new ArrayList<>();
+  private final List<TiSession> sessionList = new ArrayList<>();
 
   @After
   public void tearDown() throws Exception {
@@ -35,7 +35,7 @@ public class MetricsTest {
     client.put(ByteString.copyFromUtf8("k"), ByteString.copyFromUtf8("v"));
     Optional<ByteString> result = client.get(ByteString.copyFromUtf8("k"));
     assertTrue(result.isPresent());
-    assertEquals(result.get().toStringUtf8(), "v");
+    assertEquals("v", result.get().toStringUtf8());
     client.close();
     session.close();
   }
@@ -61,7 +61,7 @@ public class MetricsTest {
 
     Optional<ByteString> result = client2.get(ByteString.copyFromUtf8("k2"));
     assertTrue(result.isPresent());
-    assertEquals(result.get().toStringUtf8(), "v2");
+    assertEquals("v2", result.get().toStringUtf8());
 
     client2.close();
     session2.close();
@@ -82,7 +82,6 @@ public class MetricsTest {
     conf2.setMetricsPort(54321);
     try {
       TiSession.create(conf2);
-      assertEquals(1, 2);
     } catch (IllegalArgumentException e) {
       assertEquals(
           "Do dot support multiple tikv.metrics.port, which are 54321 and 12345", e.getMessage());

src/test/java/org/tikv/util/ReflectionWrapper.java

@@ -22,7 +22,7 @@ public class ReflectionWrapper {
     this.obj = obj;
   }
 
-  private Object obj;
+  private final Object obj;
 
   public Object call(String methodName, Object... args) {
     try {