Add PMD and prohibit unnecessary fully qualified class names in code (a…

…pache#4350)

* Add PMD and prohibit unnecessary fully qualified class names in code

* Extra fixes

* Remove extra unnecessary fully-qualified names

* Remove qualifiers

* Remove qualifier

api/src/main/java/io/druid/guice/JsonConfigProvider.java

@@ -48,7 +48,7 @@
  * <h3>Implementation</h3>
  * <br/>
  * The state of {@code <T>} is defined by the value of the property {@code propertyBase}.
- * This value is a json structure, decoded via {@link JsonConfigurator#configurate(java.util.Properties, String, Class)}.
+ * This value is a json structure, decoded via {@link JsonConfigurator#configurate(Properties, String, Class)}.
  * <br/>
  *
  * An example might be if DruidServerConfig.class were

api/src/main/java/io/druid/guice/LifecycleModule.java

@@ -49,8 +49,8 @@ public class LifecycleModule implements Module
    * scope.  That is, they are generally eagerly loaded because the loading operation will produce some beneficial
    * side-effect even if nothing actually directly depends on the instance.
    *
-   * This mechanism exists to allow the {@link io.druid.java.util.common.lifecycle.Lifecycle} to be the primary entry point from the injector, not to
-   * auto-register things with the {@link io.druid.java.util.common.lifecycle.Lifecycle}.  It is also possible to just bind things eagerly with Guice,
+   * This mechanism exists to allow the {@link Lifecycle} to be the primary entry point from the injector, not to
+   * auto-register things with the {@link Lifecycle}.  It is also possible to just bind things eagerly with Guice,
    * it is not clear which is actually the best approach.  This is more explicit, but eager bindings inside of modules
    * is less error-prone.
    *
@@ -70,8 +70,8 @@ public static void register(Binder binder, Class<?> clazz)
    * scope.  That is, they are generally eagerly loaded because the loading operation will produce some beneficial
    * side-effect even if nothing actually directly depends on the instance.
    *
-   * This mechanism exists to allow the {@link io.druid.java.util.common.lifecycle.Lifecycle} to be the primary entry point from the injector, not to
-   * auto-register things with the {@link io.druid.java.util.common.lifecycle.Lifecycle}.  It is also possible to just bind things eagerly with Guice,
+   * This mechanism exists to allow the {@link Lifecycle} to be the primary entry point from the injector, not to
+   * auto-register things with the {@link Lifecycle}.  It is also possible to just bind things eagerly with Guice,
    * it is not clear which is actually the best approach.  This is more explicit, but eager bindings inside of modules
    * is less error-prone.
    *
@@ -92,8 +92,8 @@ public static void register(Binder binder, Class<?> clazz, Annotation annotation
    * scope.  That is, they are generally eagerly loaded because the loading operation will produce some beneficial
    * side-effect even if nothing actually directly depends on the instance.
    *
-   * This mechanism exists to allow the {@link io.druid.java.util.common.lifecycle.Lifecycle} to be the primary entry point from the injector, not to
-   * auto-register things with the {@link io.druid.java.util.common.lifecycle.Lifecycle}.  It is also possible to just bind things eagerly with Guice,
+   * This mechanism exists to allow the {@link Lifecycle} to be the primary entry point from the injector, not to
+   * auto-register things with the {@link Lifecycle}.  It is also possible to just bind things eagerly with Guice,
    * it is not clear which is actually the best approach.  This is more explicit, but eager bindings inside of modules
    * is less error-prone.
    *
@@ -107,15 +107,15 @@ public static void register(Binder binder, Class<?> clazz, Class<? extends Annot
   }
 
   /**
-   * Registers a key to instantiate eagerly.  {@link com.google.inject.Key}s mentioned here will be pulled out of
+   * Registers a key to instantiate eagerly.  {@link Key}s mentioned here will be pulled out of
    * the injector with an injector.getInstance() call when the lifecycle is created.
    *
    * Eagerly loaded classes will *not* be automatically added to the Lifecycle unless they are bound to the proper
    * scope.  That is, they are generally eagerly loaded because the loading operation will produce some beneficial
    * side-effect even if nothing actually directly depends on the instance.
    *
-   * This mechanism exists to allow the {@link io.druid.java.util.common.lifecycle.Lifecycle} to be the primary entry point
-   * from the injector, not to auto-register things with the {@link io.druid.java.util.common.lifecycle.Lifecycle}.  It is
+   * This mechanism exists to allow the {@link Lifecycle} to be the primary entry point
+   * from the injector, not to auto-register things with the {@link Lifecycle}.  It is
    * also possible to just bind things eagerly with Guice, it is not clear which is actually the best approach.
    * This is more explicit, but eager bindings inside of modules is less error-prone.
    *

api/src/main/java/io/druid/guice/ManageLifecycle.java

@@ -29,7 +29,7 @@
 /**
  * Marks the object to be managed by {@link io.druid.java.util.common.lifecycle.Lifecycle}
  *
- * This Scope gets defined by {@link io.druid.guice.LifecycleModule}
+ * This Scope gets defined by {@link LifecycleModule}
  */
 @Target({ ElementType.TYPE, ElementType.METHOD })
 @Retention(RetentionPolicy.RUNTIME)

api/src/main/java/io/druid/guice/ManageLifecycleLast.java

@@ -29,7 +29,7 @@
 /**
  * Marks the object to be managed by {@link io.druid.java.util.common.lifecycle.Lifecycle} and set to be on Stage.LAST
  *
- * This Scope gets defined by {@link io.druid.guice.LifecycleModule}
+ * This Scope gets defined by {@link LifecycleModule}
  */
 @Target({ ElementType.TYPE, ElementType.METHOD })
 @Retention(RetentionPolicy.RUNTIME)

api/src/main/java/io/druid/guice/PolyBind.java

@@ -69,7 +69,7 @@ public static <T> ScopedBindingBuilder createChoice(
   }
 
   /**
-   * @deprecated use {@link #createChoiceWithDefault(com.google.inject.Binder, String, com.google.inject.Key, String)}
+   * @deprecated use {@link #createChoiceWithDefault(Binder, String, Key, String)}
    * instead. {@code defaultKey} argument is ignored.
    */
   @Deprecated

api/src/main/java/io/druid/timeline/DataSegmentUtils.java

@@ -67,8 +67,7 @@ public Interval apply(String identifier)
    *
    * @param dataSource the dataSource corresponding to this identifier
    * @param identifier segment identifier
-   * @return a {@link io.druid.timeline.DataSegmentUtils.SegmentIdentifierParts} object if the identifier could be
-   *         parsed, null otherwise
+   * @return a {@link DataSegmentUtils.SegmentIdentifierParts} object if the identifier could be parsed, null otherwise
    */
   public static SegmentIdentifierParts valueOf(String dataSource, String identifier)
   {

aws-common/src/main/java/io/druid/common/aws/ConfigDrivenAwsCredentialsConfigProvider.java

@@ -20,6 +20,7 @@
 package io.druid.common.aws;
 
 import com.amazonaws.AmazonClientException;
+import com.amazonaws.auth.AWSCredentials;
 import com.amazonaws.auth.AWSCredentialsProvider;
 import com.google.common.base.Strings;
 
@@ -32,10 +33,10 @@ public ConfigDrivenAwsCredentialsConfigProvider(AWSCredentialsConfig config) {
   }
 
   @Override
-  public com.amazonaws.auth.AWSCredentials getCredentials()
+  public AWSCredentials getCredentials()
   {
       if (!Strings.isNullOrEmpty(config.getAccessKey()) && !Strings.isNullOrEmpty(config.getSecretKey())) {
-        return new com.amazonaws.auth.AWSCredentials() {
+        return new AWSCredentials() {
           @Override
           public String getAWSAccessKeyId() {
             return config.getAccessKey();

aws-common/src/main/java/io/druid/common/aws/LazyFileSessionCredentialsProvider.java

@@ -19,6 +19,7 @@
 
 package io.druid.common.aws;
 
+import com.amazonaws.auth.AWSCredentials;
 import com.amazonaws.auth.AWSCredentialsProvider;
 
 public class LazyFileSessionCredentialsProvider implements AWSCredentialsProvider
@@ -42,7 +43,7 @@ private FileSessionCredentialsProvider getUnderlyingProvider() {
   }
 
   @Override
-  public com.amazonaws.auth.AWSCredentials getCredentials()
+  public AWSCredentials getCredentials()
   {
     return getUnderlyingProvider().getCredentials();
   }

bytebuffer-collections/src/main/java/io/druid/collections/spatial/split/GutmanSplitStrategy.java

@@ -53,13 +53,13 @@ public boolean needToSplit(Node node)
    *
    * Algorithm Split. Divide a set of M+1 index entries into two groups.
    *
-   * S1. [Pick first entry for each group]. Apply Algorithm {@link #pickSeeds(java.util.List)} to choose
+   * S1. [Pick first entry for each group]. Apply Algorithm {@link #pickSeeds(List)} to choose
    * two entries to be the first elements of the groups. Assign each to a group.
    *
    * S2. [Check if done]. If all entries have been assigned, stop. If one group has so few entries that all the rest
    * must be assigned to it in order for it to have the minimum number m, assign them and stop.
    *
-   * S3. [Select entry to assign]. Invoke Algorithm {@link #pickNext(java.util.List, Node[])}
+   * S3. [Select entry to assign]. Invoke Algorithm {@link #pickNext(List, Node[])}
    * to choose the next entry to assign. Add it to the group whose covering rectangle will have to be enlarged least to
    * accommodate it. Resolve ties by adding the entry to the group smaller area, then to the one with fewer entries, then
    * to either. Repeat from S2.

bytebuffer-collections/src/test/java/io/druid/collections/TestIntegerSet.java

@@ -189,7 +189,7 @@ public void testIntOverflow() throws IllegalAccessException, InstantiationExcept
         IntegerSet integerSet = IntegerSet.wrap(wrappedBitmap);
         integerSet.add(Integer.MAX_VALUE + 1);
       }
-      catch (java.lang.IllegalArgumentException ex) {
+      catch (IllegalArgumentException ex) {
         e = ex;
       }
       Assert.assertNotNull(e);

common/src/main/java/io/druid/common/config/Log4jShutdown.java

@@ -21,6 +21,7 @@
 
 import com.google.common.base.Throwables;
 import io.druid.java.util.common.ISE;
+import org.apache.logging.log4j.core.LifeCycle;
 import org.apache.logging.log4j.core.util.Cancellable;
 import org.apache.logging.log4j.core.util.ShutdownCallbackRegistry;
 
@@ -29,7 +30,7 @@
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.atomic.AtomicBoolean;
 
-public class Log4jShutdown implements ShutdownCallbackRegistry, org.apache.logging.log4j.core.LifeCycle
+public class Log4jShutdown implements ShutdownCallbackRegistry, LifeCycle
 {
   private static final long SHUTDOWN_WAIT_TIMEOUT = 60000;
 

common/src/main/java/io/druid/common/utils/VMUtils.java

@@ -49,9 +49,8 @@ public static long safeGetThreadCpuTime()
    *
    * @return total CPU time for the current thread in nanoseconds.
    *
-   * @throws java.lang.UnsupportedOperationException if the Java
-   *                                                 virtual machine does not support CPU time measurement for
-   *                                                 the current thread.
+   * @throws UnsupportedOperationException if the Java virtual machine does not support CPU time measurement for
+   * the current thread.
    */
   public static long getCurrentThreadCpuTime()
   {

extendedset/src/main/java/io/druid/extendedset/intset/ConciseSet.java

@@ -25,6 +25,7 @@
 import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
+import java.io.Serializable;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -61,7 +62,7 @@
  * @author Alessandro Colantonio
  * @version $Id$
  */
-public class ConciseSet extends AbstractIntSet implements java.io.Serializable
+public class ConciseSet extends AbstractIntSet implements Serializable
 {
   /**
    * generated serial ID

extendedset/src/main/java/io/druid/extendedset/intset/ImmutableConciseSet.java

@@ -21,6 +21,7 @@
 import com.google.common.collect.UnmodifiableIterator;
 import com.google.common.primitives.Ints;
 import io.druid.extendedset.utilities.IntList;
+import org.roaringbitmap.IntIterator;
 
 import java.nio.ByteBuffer;
 import java.nio.IntBuffer;
@@ -1000,7 +1001,7 @@ public WordIterator newWordIterator()
     return new WordIterator();
   }
 
-  public class WordIterator implements org.roaringbitmap.IntIterator, Cloneable
+  public class WordIterator implements IntIterator, Cloneable
   {
     private int startIndex;
     private int wordsWalked;

extensions-contrib/ambari-metrics-emitter/src/main/java/io/druid/emitter/ambari/metrics/SendAllTimelineEventConverter.java

@@ -30,7 +30,7 @@
 import org.apache.hadoop.metrics2.sink.timeline.TimelineMetric;
 
 /**
- * Emits all the events instance of {@link com.metamx.emitter.service.ServiceMetricEvent}.
+ * Emits all the events instance of {@link ServiceMetricEvent}.
  * <p>
  * All the dimensions will be retained and lexicographically order using dimensions name.
  * <p>

extensions-contrib/cassandra-storage/src/main/java/io/druid/storage/cassandra/CassandraDruidModule.java

@@ -20,6 +20,7 @@
 package io.druid.storage.cassandra;
 
 import com.fasterxml.jackson.core.Version;
+import com.fasterxml.jackson.databind.Module;
 import com.google.common.collect.ImmutableList;
 import com.google.inject.Binder;
 import com.google.inject.Key;
@@ -54,10 +55,10 @@ public void configure(Binder binder)
   }
 
   @Override
-  public List<? extends com.fasterxml.jackson.databind.Module> getJacksonModules()
+  public List<? extends Module> getJacksonModules()
   {
     return ImmutableList.of(
-        new com.fasterxml.jackson.databind.Module()
+        new Module()
         {
           @Override
           public String getModuleName()

extensions-contrib/graphite-emitter/src/main/java/io/druid/emitter/graphite/SendAllGraphiteEventConverter.java

@@ -31,7 +31,7 @@
 import java.util.concurrent.TimeUnit;
 
 /**
- * Emits all the events instance of {@link com.metamx.emitter.service.ServiceMetricEvent}.
+ * Emits all the events instance of {@link ServiceMetricEvent}.
  * <p>
  * All the dimensions will be retained and lexicographically order using dimensions name.
  * <p>

extensions-contrib/orc-extensions/src/test/java/io/druid/data/input/orc/OrcIndexGeneratorJobTest.java

@@ -59,6 +59,7 @@
 import org.apache.orc.CompressionKind;
 import org.apache.orc.OrcFile;
 import org.apache.orc.TypeDescription;
+import org.apache.orc.Writer;
 import org.joda.time.DateTime;
 import org.joda.time.DateTimeComparator;
 import org.joda.time.Interval;
@@ -141,7 +142,7 @@ private File writeDataToLocalOrcFile(File outputDir, List<String> data) throws I
         .addField("host", TypeDescription.createString())
         .addField("visited_num", TypeDescription.createInt());
     Configuration conf = new Configuration();
-    org.apache.orc.Writer writer = OrcFile.createWriter(
+    Writer writer = OrcFile.createWriter(
         new Path(outputFile.getPath()),
         OrcFile.writerOptions(conf)
             .setSchema(schema)

extensions-contrib/sqlserver-metadata-storage/src/main/java/io/druid/metadata/storage/sqlserver/SQLServerConnector.java

@@ -126,7 +126,7 @@ public class SQLServerConnector extends SQLMetadataConnector
    * <p>
    *
    * @see <a href="https://github.com/spring-projects/spring-framework/blob/v4.3.2.RELEASE/spring-jdbc/src/main/java/org/springframework/jdbc/support/SQLStateSQLExceptionTranslator.java">Spring Framework SQLStateSQLExceptionTranslator</a>
-   * @see java.sql.SQLException#getSQLState()
+   * @see SQLException#getSQLState()
    */
   private final Set<String> TRANSIENT_SQL_CLASS_CODES = new HashSet<>(Arrays.asList(
       "08", "53", "54", "57", "58", // Resource Failures
@@ -265,7 +265,7 @@ public DBI getDBI()
    *
    * {@inheritDoc}
    *
-   * @see java.sql.SQLException#getSQLState()
+   * @see SQLException#getSQLState()
    *
    */
   @Override

extensions-contrib/sqlserver-metadata-storage/src/main/java/io/druid/metadata/storage/sqlserver/SQLServerMetadataStorageModule.java

@@ -18,6 +18,7 @@
  */
 package io.druid.metadata.storage.sqlserver;
 
+import com.fasterxml.jackson.databind.Module;
 import com.google.common.collect.ImmutableList;
 import com.google.inject.Binder;
 import com.google.inject.Key;
@@ -44,7 +45,7 @@ public SQLServerMetadataStorageModule()
   }
 
   @Override
-  public List<? extends com.fasterxml.jackson.databind.Module> getJacksonModules()
+  public List<? extends Module> getJacksonModules()
   {
     return ImmutableList.of();
   }

extensions-core/avro-extensions/src/test/java/io/druid/data/input/AvroStreamInputRowParserTest.java

@@ -19,6 +19,7 @@
 package io.druid.data.input;
 
 import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.Module;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.google.common.base.Function;
@@ -121,7 +122,7 @@ public void before()
   {
     jsonMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
     jsonMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
-    for (com.fasterxml.jackson.databind.Module jacksonModule : new AvroExtensionsModule().getJacksonModules()) {
+    for (Module jacksonModule : new AvroExtensionsModule().getJacksonModules()) {
       jsonMapper.registerModule(jacksonModule);
     }
   }

extensions-core/caffeine-cache/src/main/java/io/druid/client/cache/CaffeineCache.java

@@ -118,7 +118,7 @@ public void close(String namespace)
   @Override
   public io.druid.client.cache.CacheStats getStats()
   {
-    final com.github.benmanes.caffeine.cache.stats.CacheStats stats = cache.stats();
+    final CacheStats stats = cache.stats();
     final long size = cache
         .policy().eviction()
         .map(eviction -> eviction.isWeighted() ? eviction.weightedSize() : OptionalLong.empty())

extensions-core/kafka-extraction-namespace/src/main/java/io/druid/query/lookup/KafkaLookupExtractorFactory.java

@@ -43,6 +43,7 @@
 import kafka.consumer.KafkaStream;
 import kafka.consumer.Whitelist;
 import kafka.javaapi.consumer.ConsumerConnector;
+import kafka.javaapi.consumer.ZookeeperConsumerConnector;
 import kafka.message.MessageAndMetadata;
 import kafka.serializer.Decoder;
 
@@ -294,7 +295,7 @@ public void onFailure(Throwable t)
   // Overridden in tests
   ConsumerConnector buildConnector(Properties properties)
   {
-    return new kafka.javaapi.consumer.ZookeeperConsumerConnector(
+    return new ZookeeperConsumerConnector(
         new ConsumerConfig(properties)
     );
   }

extensions-core/kafka-extraction-namespace/src/test/java/io/druid/query/lookup/TestKafkaExtractionCluster.java

@@ -42,6 +42,7 @@
 import kafka.utils.Time;
 import kafka.utils.ZKStringSerializer$;
 import org.I0Itec.zkclient.ZkClient;
+import org.I0Itec.zkclient.exception.ZkException;
 import org.apache.curator.test.TestingServer;
 import org.apache.zookeeper.CreateMode;
 import org.joda.time.DateTime;
@@ -199,7 +200,7 @@ public void close() throws Exception
           try {
             zkClient.deleteRecursive(zkKafkaPath);
           }
-          catch (org.I0Itec.zkclient.exception.ZkException ex) {
+          catch (ZkException ex) {
             log.warn(ex, "error deleting %s zk node", zkKafkaPath);
           }
         }