build: Add default constructor and javadoc for metrics, nat, pki, plugins, services, testutil, util (#7071)

Signed-off-by: Usman Saleem <usman@usmans.info>

metrics/core/src/main/java/org/hyperledger/besu/metrics/MetricCategoryRegistryImpl.java

@@ -25,6 +25,9 @@ public class MetricCategoryRegistryImpl implements MetricCategoryRegistry {
 
   private final List<MetricCategory> metricCategories = new ArrayList<>();
 
+  /** Default constructor */
+  public MetricCategoryRegistryImpl() {}
+
   /**
    * Gets metric categories.
    *

metrics/core/src/main/java/org/hyperledger/besu/metrics/MetricsConfigurationModule.java

@@ -24,6 +24,9 @@ import dagger.Provides;
 /** Dagger module for providing the {@link MetricsConfiguration} instance. */
 @Module
 public class MetricsConfigurationModule {
+  /** Default constructor */
+  public MetricsConfigurationModule() {}
+
   @Provides
   @Singleton
   MetricsConfiguration provideMetricsConfiguration() {

metrics/core/src/main/java/org/hyperledger/besu/metrics/MetricsSystemModule.java

@@ -28,6 +28,8 @@ import dagger.Provides;
  */
 @Module
 public class MetricsSystemModule {
+  /** Default constructor */
+  public MetricsSystemModule() {}
 
   @Provides
   @Singleton

metrics/core/src/main/java/org/hyperledger/besu/metrics/noop/NoOpMetricsSystem.java

@@ -73,6 +73,9 @@ public class NoOpMetricsSystem implements ObservableMetricsSystem {
   public static final LabelledGauge NO_OP_LABELLED_3_GAUGE =
       new LabelledGaugeNoOpMetric(3, NO_OP_GAUGE);
 
+  /** Default constructor */
+  public NoOpMetricsSystem() {}
+
   @Override
   public LabelledMetric<Counter> createLabelledCounter(
       final MetricCategory category,

metrics/core/src/main/java/org/hyperledger/besu/metrics/noop/NoOpValueCollector.java

@@ -24,6 +24,9 @@ import java.util.function.DoubleSupplier;
 public class NoOpValueCollector implements LabelledGauge {
   private final List<String> labelValuesCreated = new ArrayList<>();
 
+  /** Default constructor */
+  public NoOpValueCollector() {}
+
   @Override
   public synchronized void labels(final DoubleSupplier valueSupplier, final String... labelValues) {
     final String labelValuesString = String.join(",", labelValues);

metrics/rocksdb/src/main/java/org/hyperledger/besu/metrics/rocksdb/RocksDBStats.java

@@ -164,6 +164,9 @@ public class RocksDBStats {
     HistogramType.READ_NUM_MERGE_OPERANDS,
   };
 
+  /** Default constructor */
+  private RocksDBStats() {}
+
   /**
    * Register rocks db metrics.
    *

nat/src/main/java/org/hyperledger/besu/nat/docker/DockerDetector.java

@@ -25,6 +25,8 @@ import java.util.stream.Stream;
 
 /** The Docker detector. */
 public class DockerDetector implements NatMethodDetector {
+  /** Default constructor */
+  public DockerDetector() {}
 
   @Override
   public Optional<NatMethod> detect() {

nat/src/main/java/org/hyperledger/besu/nat/docker/HostBasedIpDetector.java

@@ -25,6 +25,9 @@ public class HostBasedIpDetector implements IpDetector {
 
   private static final String HOSTNAME = "HOST_IP";
 
+  /** Default constructor */
+  public HostBasedIpDetector() {}
+
   @Override
   @SuppressWarnings("AddressSelection")
   public Optional<String> detectAdvertisedIp() {

nat/src/main/java/org/hyperledger/besu/nat/kubernetes/KubernetesDetector.java

@@ -32,6 +32,9 @@ public class KubernetesDetector implements NatMethodDetector {
       Optional.ofNullable(System.getenv("KUBERNETES_SERVICE_HOST"));
   private static final Path KUBERNETES_WATERMARK_FILE = Paths.get("var/run/secrets/kubernetes.io");
 
+  /** Default constructor */
+  public KubernetesDetector() {}
+
   @Override
   public Optional<NatMethod> detect() {
     return KUBERNETES_SERVICE_HOST

pki/src/main/java/org/hyperledger/besu/pki/crl/CRLUtil.java

@@ -27,6 +27,8 @@ import java.util.stream.Collectors;
 
 /** The CRL util. */
 public class CRLUtil {
+  /** Default constructor */
+  private CRLUtil() {}
 
   /**
    * Load CRLs cert store.

plugins/rocksdb/src/main/java/org/hyperledger/besu/plugin/services/storage/rocksdb/configuration/RocksDBConfigurationBuilder.java

@@ -31,6 +31,9 @@ public class RocksDBConfigurationBuilder {
   private int backgroundThreadCount = DEFAULT_BACKGROUND_THREAD_COUNT;
   private boolean isHighSpec = DEFAULT_IS_HIGH_SPEC;
 
+  /** Instantiates a new Rocks db configuration builder. */
+  public RocksDBConfigurationBuilder() {}
+
   /**
    * Database dir.
    *

services/kvstore/src/main/java/org/hyperledger/besu/services/kvstore/InMemoryStoragePlugin.java

@@ -40,6 +40,9 @@ public class InMemoryStoragePlugin implements BesuPlugin {
   private InMemoryKeyValueStorageFactory factory;
   private InMemoryKeyValueStorageFactory privacyFactory;
 
+  /** Default constructor */
+  public InMemoryStoragePlugin() {}
+
   @Override
   public void register(final BesuContext context) {
     LOG.debug("Registering plugin");

services/kvstore/src/main/java/org/hyperledger/besu/services/kvstore/SegmentedInMemoryKeyValueStorage.java

@@ -290,6 +290,9 @@ public class SegmentedInMemoryKeyValueStorage
     /** protected access to deletedValues set for the transaction. */
     protected Map<SegmentIdentifier, Set<Bytes>> removedKeys = new HashMap<>();
 
+    /** Default constructor */
+    public SegmentedInMemoryTransaction() {}
+
     @Override
     public void put(
         final SegmentIdentifier segmentIdentifier, final byte[] key, final byte[] value) {

testutil/src/main/java/org/hyperledger/besu/kvstore/AbstractKeyValueStorageTest.java

@@ -40,6 +40,8 @@ import org.junit.jupiter.api.Test;
 /** The Abstract key value storage test. */
 @Disabled
 public abstract class AbstractKeyValueStorageTest {
+  /** Default Constructor */
+  protected AbstractKeyValueStorageTest() {}
 
   /**
    * Create store key value storage.

testutil/src/main/java/org/hyperledger/besu/testutil/MockExecutorService.java

@@ -36,6 +36,14 @@ public class MockExecutorService implements ExecutorService {
 
   private final List<ExecutorTask<?>> tasks = new ArrayList<>();
 
+  /** Default constructor */
+  public MockExecutorService() {}
+
+  /**
+   * Gets tasks.
+   *
+   * @return the tasks
+   */
   /**
    * Gets futures.
    *

testutil/src/main/java/org/hyperledger/besu/testutil/MockScheduledExecutor.java

@@ -25,6 +25,8 @@ import java.util.concurrent.TimeoutException;
 
 /** The mock scheduled executor */
 public class MockScheduledExecutor extends MockExecutorService implements ScheduledExecutorService {
+  /** Default constructor */
+  public MockScheduledExecutor() {}
 
   @Override
   public ScheduledFuture<?> schedule(

testutil/src/main/java/org/hyperledger/enclave/testutil/EnclaveKeyUtils.java

@@ -34,6 +34,9 @@ import org.slf4j.LoggerFactory;
 public class EnclaveKeyUtils {
   private static final Logger LOG = LoggerFactory.getLogger(EnclaveKeyUtils.class);
 
+  /** Default constructor */
+  private EnclaveKeyUtils() {}
+
   /**
    * Utility method to load the enclave public key. Possible input values are the names of the *.pub
    * files in the resources folder.

testutil/src/main/java/org/hyperledger/enclave/testutil/TesseraTestHarnessFactory.java

@@ -30,6 +30,9 @@ import org.testcontainers.containers.Network;
 public class TesseraTestHarnessFactory {
   private static final String storage = "memory";
 
+  /** Default constructor */
+  private TesseraTestHarnessFactory() {}
+
   /**
    * Create tessera test harness.
    *