intelliJ inspections cleanup

benchmarks/src/main/java/org/apache/druid/benchmark/query/CachingClusteredClientBenchmark.java

@@ -564,7 +564,7 @@ public void registerSegmentCallback(Executor exec, SegmentCallback callback)
     }
   }
 
-  private class SimpleQueryRunner implements QueryRunner<Object>
+  private static class SimpleQueryRunner implements QueryRunner<Object>
   {
     private final QueryRunnerFactoryConglomerate conglomerate;
     private final QueryableIndexSegment segment;
@@ -597,7 +597,7 @@ public Sequence<Object> run(QueryPlus<Object> queryPlus, ResponseContext respons
     }
   }
 
-  private class SingleSegmentDruidServer extends QueryableDruidServer<SimpleQueryRunner>
+  private static class SingleSegmentDruidServer extends QueryableDruidServer<SimpleQueryRunner>
   {
     SingleSegmentDruidServer(DruidServer server, SimpleQueryRunner runner)
     {

core/src/main/java/org/apache/druid/java/util/emitter/core/ParametrizedUriExtractor.java

@@ -38,7 +38,7 @@ public class ParametrizedUriExtractor implements UriExtractor
   public ParametrizedUriExtractor(String uriPattern)
   {
     this.uriPattern = uriPattern;
-    Matcher keyMatcher = Pattern.compile("\\{([^\\}]+)\\}").matcher(uriPattern);
+    Matcher keyMatcher = Pattern.compile("\\{([^}]+)}").matcher(uriPattern);
     params = new HashSet<>();
     while (keyMatcher.find()) {
       params.add(keyMatcher.group(1));

extendedset/src/test/java/org/apache/druid/extendedset/intset/ImmutableConciseSetTest.java

@@ -1317,19 +1317,16 @@ public void testComplement8()
   @Test
   public void testComplement9()
   {
-    final List<Integer> lengths = new ArrayList<Integer>();
-    lengths.addAll(
-        Arrays.asList(
-            35,
-            31,
-            32,
-            1,
-            0,
-            31 * 3,
-            1024,
-            ConciseSetUtils.MAX_ALLOWED_INTEGER
-        )
-    );
+    final List<Integer> lengths = new ArrayList<>(Arrays.asList(
+        35,
+        31,
+        32,
+        1,
+        0,
+        31 * 3,
+        1024,
+        ConciseSetUtils.MAX_ALLOWED_INTEGER
+    ));
     final Random random = new Random(701534702L);
     for (int i = 0; i < 5; ++i) {
       lengths.add(random.nextInt(ConciseSetUtils.MAX_ALLOWED_INTEGER + 1));

extensions-contrib/materialized-view-selection/src/main/java/org/apache/druid/query/materializedview/MaterializedViewUtils.java

@@ -47,9 +47,8 @@ public class MaterializedViewUtils
    */
   public static Set<String> getRequiredFields(Query query)
   {
-    Set<String> dimensions = new HashSet<>();
     Set<String> dimsInFilter = null == query.getFilter() ? new HashSet<String>() : query.getFilter().getRequiredColumns();
-    dimensions.addAll(dimsInFilter);
+    Set<String> dimensions = new HashSet<>(dimsInFilter);
 
     if (query instanceof TopNQuery) {
       TopNQuery q = (TopNQuery) query;

extensions-contrib/moving-average-query/src/main/java/org/apache/druid/query/movingaverage/MovingAverageQuery.java

@@ -129,8 +129,7 @@ public MovingAverageQuery(
     verifyOutputNames(this.dimensions, this.aggregatorSpecs, this.postAggregatorSpecs);
 
     // build combined list of aggregators and averagers so that limit spec building is happy
-    List<AggregatorFactory> combinedAggregatorSpecs = new ArrayList<>();
-    combinedAggregatorSpecs.addAll(this.aggregatorSpecs);
+    List<AggregatorFactory> combinedAggregatorSpecs = new ArrayList<>(this.aggregatorSpecs);
     for (AveragerFactory<?, ?> avg : this.averagerSpecs) {
       combinedAggregatorSpecs.add(new AveragerFactoryWrapper(avg, ""));
     }

extensions-core/datasketches/src/test/java/org/apache/druid/query/aggregation/datasketches/theta/SketchAggregationTest.java

@@ -504,7 +504,7 @@ private void assertPostAggregatorSerde(PostAggregator agg) throws Exception
     );
   }
 
-  public static final String readFileFromClasspathAsString(String fileName) throws IOException
+  public static String readFileFromClasspathAsString(String fileName) throws IOException
   {
     return Files.asCharSource(
         new File(SketchAggregationTest.class.getClassLoader().getResource(fileName).getFile()),

extensions-core/datasketches/src/test/java/org/apache/druid/query/aggregation/datasketches/theta/SketchAggregationWithSimpleDataTest.java

@@ -313,7 +313,7 @@ public void testTopNQueryWithSketchConstant() throws Exception
     Assert.assertEquals("product_2", value3.getDimensionValue("product"));
   }
 
-  public static final String readFileFromClasspathAsString(String fileName) throws IOException
+  public static String readFileFromClasspathAsString(String fileName) throws IOException
   {
     return Files.asCharSource(
         new File(SketchAggregationTest.class.getClassLoader().getResource(fileName).getFile()),

extensions-core/datasketches/src/test/java/org/apache/druid/query/aggregation/datasketches/theta/oldapi/OldApiSketchAggregationTest.java

@@ -253,7 +253,7 @@ private void assertPostAggregatorSerde(PostAggregator agg) throws Exception
     );
   }
 
-  public static final String readFileFromClasspathAsString(String fileName) throws IOException
+  public static String readFileFromClasspathAsString(String fileName) throws IOException
   {
     return Files.asCharSource(
         new File(OldApiSketchAggregationTest.class.getClassLoader().getResource(fileName).getFile()),

extensions-core/stats/src/main/java/org/apache/druid/query/aggregation/teststats/PvaluefromZscorePostAggregator.java

@@ -65,9 +65,7 @@ public PvaluefromZscorePostAggregator(
   @Override
   public Set<String> getDependentFields()
   {
-    Set<String> dependentFields = new HashSet<>();
-
-    dependentFields.addAll(zScore.getDependentFields());
+    Set<String> dependentFields = new HashSet<>(zScore.getDependentFields());
 
     return dependentFields;
   }

indexing-hadoop/src/main/java/org/apache/druid/indexer/Bucket.java

@@ -113,7 +113,7 @@ private static int sizes(byte[]... parts)
     return size;
   }
 
-  public static final Pair<Bucket, byte[]> fromGroupKey(byte[] keyBytes)
+  public static Pair<Bucket, byte[]> fromGroupKey(byte[] keyBytes)
   {
     ByteBuffer buf = ByteBuffer.wrap(keyBytes);
 

indexing-hadoop/src/main/java/org/apache/druid/indexer/DetermineHashedPartitionsJob.java

@@ -132,7 +132,7 @@ public boolean run()
       try {
         if (!groupByJob.waitForCompletion(true)) {
           log.error("Job failed: %s", groupByJob.getJobID());
-          failureCause = Utils.getFailureMessage(groupByJob, config.JSON_MAPPER);
+          failureCause = Utils.getFailureMessage(groupByJob, HadoopDruidIndexerConfig.JSON_MAPPER);
           return false;
         }
       }
@@ -154,7 +154,7 @@ public boolean run()
         if (!Utils.exists(groupByJob, fileSystem, intervalInfoPath)) {
           throw new ISE("Path[%s] didn't exist!?", intervalInfoPath);
         }
-        List<Interval> intervals = config.JSON_MAPPER.readValue(
+        List<Interval> intervals = HadoopDruidIndexerConfig.JSON_MAPPER.readValue(
             Utils.openInputStream(groupByJob, intervalInfoPath),
             new TypeReference<List<Interval>>() {}
         );
@@ -178,7 +178,7 @@ public boolean run()
           fileSystem = partitionInfoPath.getFileSystem(groupByJob.getConfiguration());
         }
         if (Utils.exists(groupByJob, fileSystem, partitionInfoPath)) {
-          final Long numRows = config.JSON_MAPPER.readValue(
+          final Long numRows = HadoopDruidIndexerConfig.JSON_MAPPER.readValue(
               Utils.openInputStream(groupByJob, partitionInfoPath),
               Long.class
           );

indexing-hadoop/src/main/java/org/apache/druid/indexer/IndexGeneratorJob.java

@@ -281,7 +281,7 @@ public String getErrorMessage()
       return null;
     }
 
-    return Utils.getFailureMessage(job, config.JSON_MAPPER);
+    return Utils.getFailureMessage(job, HadoopDruidIndexerConfig.JSON_MAPPER);
   }
 
   private static IncrementalIndex makeIncrementalIndex(
@@ -823,16 +823,16 @@ public void doRun()
                 outputFS,
                 segmentTemplate,
                 JobHelper.INDEX_ZIP,
-                config.DATA_SEGMENT_PUSHER
+                HadoopDruidIndexerConfig.DATA_SEGMENT_PUSHER
             ),
             JobHelper.makeTmpPath(
                 new Path(config.getSchema().getIOConfig().getSegmentOutputPath()),
                 outputFS,
                 segmentTemplate,
                 context.getTaskAttemptID(),
-                config.DATA_SEGMENT_PUSHER
+                HadoopDruidIndexerConfig.DATA_SEGMENT_PUSHER
             ),
-            config.DATA_SEGMENT_PUSHER
+            HadoopDruidIndexerConfig.DATA_SEGMENT_PUSHER
         );
 
         Path descriptorPath = config.makeDescriptorInfoPath(segment);

indexing-hadoop/src/main/java/org/apache/druid/indexer/InputRowSerde.java

@@ -289,7 +289,7 @@ public Double deserialize(ByteArrayDataInput in)
     }
   }
 
-  public static final SerializeResult toBytes(
+  public static SerializeResult toBytes(
       final Map<String, IndexSerdeTypeHelper> typeHelperMap,
       final InputRow row,
       AggregatorFactory[] aggs
@@ -422,7 +422,7 @@ private static List<String> readStringArray(DataInput in) throws IOException
     return values;
   }
 
-  public static final InputRow fromBytes(
+  public static InputRow fromBytes(
       final Map<String, IndexSerdeTypeHelper> typeHelperMap,
       byte[] data,
       AggregatorFactory[] aggs

indexing-hadoop/src/main/java/org/apache/druid/indexer/JobHelper.java

@@ -81,7 +81,7 @@ public class JobHelper
   private static final int NUM_RETRIES = 8;
   private static final int SECONDS_BETWEEN_RETRIES = 2;
   private static final int DEFAULT_FS_BUFFER_SIZE = 1 << 18; // 256KB
-  private static final Pattern SNAPSHOT_JAR = Pattern.compile(".*\\-SNAPSHOT(-selfcontained)?\\.jar$");
+  private static final Pattern SNAPSHOT_JAR = Pattern.compile(".*-SNAPSHOT(-selfcontained)?\\.jar$");
 
   public static Path distributedClassPath(String path)
   {
@@ -103,8 +103,8 @@ public static Path distributedClassPath(Path base)
    */
   public static void authenticate(HadoopDruidIndexerConfig config)
   {
-    String principal = config.HADOOP_KERBEROS_CONFIG.getPrincipal();
-    String keytab = config.HADOOP_KERBEROS_CONFIG.getKeytab();
+    String principal = HadoopDruidIndexerConfig.HADOOP_KERBEROS_CONFIG.getPrincipal();
+    String keytab = HadoopDruidIndexerConfig.HADOOP_KERBEROS_CONFIG.getKeytab();
     if (!Strings.isNullOrEmpty(principal) && !Strings.isNullOrEmpty(keytab)) {
       Configuration conf = new Configuration();
       UserGroupInformation.setConfiguration(conf);
@@ -180,7 +180,7 @@ public static void setupClasspath(
     }
   }
 
-  public static final Predicate<Throwable> shouldRetryPredicate()
+  public static Predicate<Throwable> shouldRetryPredicate()
   {
     return new Predicate<Throwable>()
     {

indexing-hadoop/src/main/java/org/apache/druid/indexer/Utils.java

@@ -141,11 +141,11 @@ public static String getFailureMessage(Job failedJob, ObjectMapper jsonMapper)
       TaskCompletionEvent[] completionEvents = failedJob.getTaskCompletionEvents(0, 100);
       for (TaskCompletionEvent tce : completionEvents) {
         String[] taskDiags = failedJob.getTaskDiagnostics(tce.getTaskAttemptId());
-        String combinedTaskDiags = "";
+        StringBuilder combinedTaskDiags = new StringBuilder();
         for (String taskDiag : taskDiags) {
-          combinedTaskDiags += taskDiag;
+          combinedTaskDiags.append(taskDiag);
         }
-        taskDiagsMap.put(tce.getTaskAttemptId().toString(), combinedTaskDiags);
+        taskDiagsMap.put(tce.getTaskAttemptId().toString(), combinedTaskDiags.toString());
       }
       return jsonMapper.writeValueAsString(taskDiagsMap);
     }

indexing-hadoop/src/test/java/org/apache/druid/indexer/InputRowSerdeTest.java

@@ -57,7 +57,8 @@ public class InputRowSerdeTest
   private List<String> dims;
   private Map<String, Object> event;
 
-  {
+  static {
+    NullHandling.initializeForTests();
     new AggregatorsModule(); //registers ComplexMetric serde for hyperUnique
   }
 

indexing-hadoop/src/test/java/org/apache/druid/indexer/path/StaticPathSpecTest.java

@@ -82,7 +82,7 @@ private void testSerde(String path, Class inputFormat) throws Exception
     Assert.assertEquals(path, pathSpec.getPaths());
   }
 
-  public static final PathSpec readWriteRead(String jsonStr, ObjectMapper jsonMapper) throws Exception
+  public static PathSpec readWriteRead(String jsonStr, ObjectMapper jsonMapper) throws Exception
   {
     return jsonMapper.readValue(
         jsonMapper.writeValueAsString(

indexing-service/src/main/java/org/apache/druid/indexing/worker/executor/ExecutorLifecycleConfig.java

@@ -40,7 +40,7 @@ public class ExecutorLifecycleConfig
   private File statusFile = null;
 
   @JsonProperty
-  @Pattern(regexp = "\\{stdin\\}")
+  @Pattern(regexp = "\\{stdin}")
   private String parentStreamName = "stdin";
   @JsonProperty
   private boolean parentStreamDefined = true;

indexing-service/src/test/java/org/apache/druid/indexing/common/task/CompactionTaskRunTest.java

@@ -514,10 +514,9 @@ public void testCompactThenAppend() throws Exception
         .interval(Intervals.of("2014-01-01/2014-01-02"))
         .build();
 
-    final Set<DataSegment> expectedSegments = new HashSet<>();
     final Pair<TaskStatus, List<DataSegment>> compactionResult = runTask(compactionTask);
     Assert.assertTrue(compactionResult.lhs.isSuccess());
-    expectedSegments.addAll(compactionResult.rhs);
+    final Set<DataSegment> expectedSegments = new HashSet<>(compactionResult.rhs);
 
     final Pair<TaskStatus, List<DataSegment>> appendResult = runAppendTask();
     Assert.assertTrue(appendResult.lhs.isSuccess());