A session of compile warning hunt (#4472)

Signed-off-by: Gaël L'hopital <gael@lhopital.org>

bundles/org.openhab.core/src/main/java/org/openhab/core/cache/ExpiringCache.java

@@ -67,6 +67,7 @@ public class ExpiringCache<V> {
      * Returns the value - possibly from the cache, if it is still valid.
      */
     public synchronized @Nullable V getValue() {
+        @Nullable
         V cachedValue = value.get();
         if (cachedValue == null || isExpired()) {
             return refreshValue();
@@ -98,6 +99,7 @@ public class ExpiringCache<V> {
      * @return the new value
      */
     public synchronized @Nullable V refreshValue() {
+        @Nullable
         V freshValue = action.get();
         value = new SoftReference<>(freshValue);
         expiresAt = calcExpiresAt();

bundles/org.openhab.core/src/main/java/org/openhab/core/cache/lru/LRUMediaCache.java

@@ -132,7 +132,6 @@ public class LRUMediaCache<V> {
             // 2 clean orphan (part of a pair (file + metadata) without a corresponding partner)
             // 2-a delete a file without its metadata
             for (Path path : filesInCacheFolder) {
-                if (path != null) {
                 String fileName = path.getFileName().toString();
                 // check corresponding metadata in storage
                 V metadata = storage.get(fileName);
@@ -140,7 +139,6 @@ public class LRUMediaCache<V> {
                     Files.delete(path);
                 }
             }
-            }
             // 2-b delete metadata without corresponding file
             for (Entry<String, @Nullable V> entry : storage.stream().toList()) {
                 Path correspondingFile = cacheFolder.resolve(entry.getKey());

bundles/org.openhab.core/src/main/java/org/openhab/core/common/PoolBasedSequentialScheduledExecutorService.java

@@ -22,7 +22,6 @@ import java.util.concurrent.Callable;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executor;
-import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
 import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.RunnableFuture;
@@ -43,7 +42,7 @@ import org.slf4j.LoggerFactory;
 
 /**
  * A ScheduledExecutorService that will sequentially perform the tasks like a
- * {@link Executors#newSingleThreadScheduledExecutor} backed by a thread pool.
+ * {@link java.util.concurrent.Executors#newSingleThreadScheduledExecutor} backed by a thread pool.
  * This is a drop in replacement to a ScheduledExecutorService with one thread to avoid a lot of threads created, idling
  * most of the time and wasting memory on low-end devices.
  *

bundles/org.openhab.core/src/main/java/org/openhab/core/common/ThreadFactoryBuilder.java

@@ -15,8 +15,6 @@ package org.openhab.core.common;
 import static java.util.concurrent.Executors.defaultThreadFactory;
 
 import java.lang.Thread.UncaughtExceptionHandler;
-import java.util.concurrent.Executor;
-import java.util.concurrent.Executors;
 import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -25,10 +23,12 @@ import org.eclipse.jdt.annotation.Nullable;
 
 /**
  * A builder for {@link ThreadFactory} instances. This builder is intended to be used for creating thread factories to
- * be used, e.g., when creating {@link Executor}s via the {@link Executors} utility methods.
+ * be used, e.g., when creating {@link java.util.concurrent.Executor}s via the {@link java.util.concurrent.Executors}
+ * utility methods.
  * <p>
  * The built {@link ThreadFactory} uses a wrapped {@link ThreadFactory} to create threads (defaulting to
- * {@link Executors#defaultThreadFactory()}, and then overwrites thread properties as indicated in the build process.
+ * {@link java.util.concurrent.Executors#defaultThreadFactory()}, and then overwrites thread properties as indicated in
+ * the build process.
  *
  * @author Henning Sudbrock - Initial contribution
  */
@@ -60,7 +60,7 @@ public class ThreadFactoryBuilder {
     /**
      * Sets the wrapped thread factory used to create threads.
      * <p>
-     * If set to null, {@link Executors#defaultThreadFactory()} is used.
+     * If set to null, {@link java.util.concurrent.Executors#defaultThreadFactory()} is used.
      * <p>
      * Defaults to null.
      *

bundles/org.openhab.core/src/main/java/org/openhab/core/common/registry/AbstractRegistry.java

@@ -442,9 +442,9 @@ public abstract class AbstractRegistry<@NonNull E extends Identifiable<K>, @NonN
         }
         elementsAdded.forEach(this::notifyListenersAboutAddedElement);
 
-        if (provider instanceof ManagedProvider && providerClazz != null && readyService != null) {
+        if (provider instanceof ManagedProvider && providerClazz instanceof Class clazz
-            readyService.markReady(
+                && readyService instanceof ReadyService rs) {
-                    new ReadyMarker("managed", providerClazz.getSimpleName().replace("Provider", "").toLowerCase()));
+            rs.markReady(new ReadyMarker("managed", clazz.getSimpleName().replace("Provider", "").toLowerCase()));
         }
         logger.debug("Provider \"{}\" has been added.", provider.getClass().getName());
     }
@@ -688,9 +688,9 @@ public abstract class AbstractRegistry<@NonNull E extends Identifiable<K>, @NonN
      * @param event the event
      */
     protected void postEvent(Event event) {
-        if (eventPublisher != null) {
+        if (eventPublisher instanceof EventPublisher ep) {
             try {
-                eventPublisher.post(event);
+                ep.post(event);
             } catch (RuntimeException ex) {
                 logger.error("Cannot post event of type \"{}\".", event.getType(), ex);
             }

bundles/org.openhab.core/src/main/java/org/openhab/core/events/AbstractEvent.java

@@ -61,9 +61,9 @@ public abstract class AbstractEvent implements Event {
     public int hashCode() {
         final int prime = 31;
         int result = 1;
-        result = prime * result + ((payload == null) ? 0 : payload.hashCode());
+        result = prime * result + payload.hashCode();
-        result = prime * result + ((source == null) ? 0 : source.hashCode());
+        result = prime * result + (source instanceof String local ? local.hashCode() : 0);
-        result = prime * result + ((topic == null) ? 0 : topic.hashCode());
+        result = prime * result + topic.hashCode();
         return result;
     }
 
@@ -79,11 +79,7 @@ public abstract class AbstractEvent implements Event {
             return false;
         }
         AbstractEvent other = (AbstractEvent) obj;
-        if (payload == null) {
+        if (!payload.equals(other.payload)) {
-            if (other.payload != null) {
-                return false;
-            }
-        } else if (!payload.equals(other.payload)) {
             return false;
         }
         if (source == null) {
@@ -93,11 +89,7 @@ public abstract class AbstractEvent implements Event {
         } else if (!source.equals(other.source)) {
             return false;
         }
-        if (topic == null) {
+        if (!topic.equals(other.topic)) {
-            if (other.topic != null) {
-                return false;
-            }
-        } else if (!topic.equals(other.topic)) {
             return false;
         }
         return true;

bundles/org.openhab.core/src/main/java/org/openhab/core/events/system/SystemEventFactory.java

@@ -19,7 +19,6 @@ import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.core.events.AbstractEventFactory;
 import org.openhab.core.events.Event;
 import org.openhab.core.events.EventFactory;
-import org.openhab.core.types.Type;
 import org.osgi.service.component.annotations.Component;
 
 /**
@@ -38,7 +37,7 @@ public class SystemEventFactory extends AbstractEventFactory {
     }
 
     /**
-     * Creates a trigger event from a {@link Type}.
+     * Creates a trigger event from a {@link org.openhab.core.types.Type}.
      *
      * @param startlevel Startlevel of system
      * @return Created start level event.

bundles/org.openhab.core/src/main/java/org/openhab/core/i18n/LocalizedKey.java

@@ -46,7 +46,7 @@ public class LocalizedKey {
         final int prime = 31;
         int result = 1;
         result = prime * result + key.hashCode();
-        result = prime * result + ((locale != null) ? locale.hashCode() : 0);
+        result = prime * result + (locale instanceof String string ? string.hashCode() : 0);
         return result;
     }
 

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/auth/AuthenticationManagerImpl.java

@@ -48,9 +48,7 @@ public class AuthenticationManagerImpl implements AuthenticationManager {
                 unmatched = false;
                 try {
                     Authentication authentication = provider.authenticate(credentials);
-                    if (authentication != null) {
                     return authentication;
-                    }
                 } catch (AuthenticationException e) {
                     logger.info("Failed to authenticate credentials {} with provider {}", credentials.getClass(),
                             provider, e);

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/auth/ManagedUserProvider.java

@@ -13,17 +13,15 @@
 package org.openhab.core.internal.auth;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
-import org.openhab.core.auth.ManagedUser;
 import org.openhab.core.auth.User;
 import org.openhab.core.common.registry.DefaultAbstractManagedProvider;
-import org.openhab.core.common.registry.ManagedProvider;
 import org.openhab.core.storage.StorageService;
 import org.osgi.service.component.annotations.Activate;
 import org.osgi.service.component.annotations.Component;
 import org.osgi.service.component.annotations.Reference;
 
 /**
- * A {@link ManagedProvider} for {@link ManagedUser} entities
+ * A {@link org.openhab.core.common.registry.ManagedProvider} for {@link org.openhab.core.auth.ManagedUser} entities
  *
  * @author Yannick Schaus - initial contribution
  */

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/common/AbstractInvocationHandler.java

@@ -117,8 +117,8 @@ abstract class AbstractInvocationHandler<T> {
         } else {
             logger.debug(MSG_TIMEOUT_Q, timeout, toString(invocation.getInvocationStack()));
         }
-        if (timeoutHandler != null) {
+        if (timeoutHandler instanceof Runnable handler) {
-            timeoutHandler.run();
+            handler.run();
         }
     }
 

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/events/OSGiEventManager.java

@@ -17,7 +17,6 @@ import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArraySet;
 
-import org.openhab.core.events.Event;
 import org.openhab.core.events.EventFactory;
 import org.openhab.core.events.EventSubscriber;
 import org.osgi.service.component.ComponentContext;
@@ -33,8 +32,8 @@ import org.osgi.service.event.EventHandler;
  * The {@link OSGiEventManager} provides an OSGi based default implementation of the openHAB event bus.
  *
  * The OSGiEventHandler tracks {@link EventSubscriber}s and {@link EventFactory}s, receives OSGi events (by
- * implementing the OSGi {@link EventHandler} interface) and dispatches the received OSGi events as OH {@link Event}s
+ * implementing the OSGi {@link EventHandler} interface) and dispatches the received OSGi events
- * to the {@link EventSubscriber}s if the provided filter applies.
+ * as OH {@link org.openhab.core.events.Event}s to the {@link EventSubscriber}s if the provided filter applies.
  *
  * @author Stefan Bußweiler - Initial contribution
  * @author Markus Rathgeb - Return on received events as fast as possible (handle event in another thread)

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/i18n/I18nProviderImpl.java

@@ -22,7 +22,6 @@ import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
-import java.util.ResourceBundle;
 import java.util.Set;
 
 import javax.measure.Quantity;
@@ -100,7 +99,8 @@ import org.slf4j.LoggerFactory;
  * and {@link LocationProvider} service interfaces.
  *
  * <p>
- * This implementation uses the i18n mechanism of Java ({@link ResourceBundle}) to translate a given key into text. The
+ * This implementation uses the i18n mechanism of Java ({@link java.util.ResourceBundle}) to translate a
+ * given key into text. The
  * resources must be placed under the specific directory {@link LanguageResourceBundleManager#RESOURCE_DIRECTORY} within
  * the certain modules. Each module is tracked in the platform by using the {@link ResourceBundleTracker} and managed by
  * using one certain {@link LanguageResourceBundleManager} which is responsible for the translation.
@@ -134,7 +134,6 @@ public class I18nProviderImpl
     public static final String REGION = "region";
     public static final String VARIANT = "variant";
     private @Nullable Locale locale;
-    private @Nullable String currencyCode;
 
     // TranslationProvider
     private final ResourceBundleTracker resourceBundleTracker;
@@ -301,7 +300,7 @@ public class I18nProviderImpl
 
         if (oldTimeZone != null && this.timeZone == null) {
             logger.info("Time zone is not set, falling back to the default time zone.");
-        } else if (this.timeZone != null && !this.timeZone.equals(oldTimeZone)) {
+        } else if (this.timeZone instanceof ZoneId zId && !zId.equals(oldTimeZone)) {
             logger.info("Time zone set to '{}'.", this.timeZone);
         }
     }

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/i18n/LanguageResourceBundleManager.java

@@ -183,9 +183,7 @@ public class LanguageResourceBundleManager {
             ResourceBundle resourceBundle = ResourceBundle.getBundle(resourceName, locale, this.resourceClassLoader,
                     Control.getNoFallbackControl(Control.FORMAT_PROPERTIES));
 
-            if (resourceBundle != null) {
             return resourceBundle.getString(key);
-            }
         } catch (Exception ex) {
             // nothing to do
         }

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/items/ItemBuilderFactoryImpl.java

@@ -20,7 +20,6 @@ import org.openhab.core.items.Item;
 import org.openhab.core.items.ItemBuilder;
 import org.openhab.core.items.ItemBuilderFactory;
 import org.openhab.core.items.ItemFactory;
-import org.openhab.core.library.CoreItemFactory;
 import org.osgi.service.component.annotations.Activate;
 import org.osgi.service.component.annotations.Component;
 import org.osgi.service.component.annotations.Reference;
@@ -28,8 +27,8 @@ import org.osgi.service.component.annotations.ReferenceCardinality;
 import org.osgi.service.component.annotations.ReferencePolicy;
 
 /**
- * Provides an {@link ItemBuilder} with all available {@link ItemFactory}s set. The {@link CoreItemFactory} will always
+ * Provides an {@link ItemBuilder} with all available {@link ItemFactory}s set.
- * be present.
+ * The {@link org.openhab.core.library.CoreItemFactory} will always be present.
  *
  * @author Henning Treu - Initial contribution
  */

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/items/ItemRegistryImpl.java

@@ -156,7 +156,6 @@ public class ItemRegistryImpl extends AbstractRegistry<Item, String, ItemProvide
 
     private void addToGroupItems(Item item, List<String> groupItemNames) {
         for (String groupName : groupItemNames) {
-            if (groupName != null) {
             try {
                 if (getItem(groupName) instanceof GroupItem groupItem) {
                     groupItem.addMember(item);
@@ -166,11 +165,9 @@ public class ItemRegistryImpl extends AbstractRegistry<Item, String, ItemProvide
             }
         }
     }
-    }
 
     private void replaceInGroupItems(Item oldItem, Item newItem, List<String> groupItemNames) {
         for (String groupName : groupItemNames) {
-            if (groupName != null) {
             try {
                 if (getItem(groupName) instanceof GroupItem groupItem) {
                     groupItem.replaceMember(oldItem, newItem);
@@ -180,7 +177,6 @@ public class ItemRegistryImpl extends AbstractRegistry<Item, String, ItemProvide
             }
         }
     }
-    }
 
     /**
      * An item should be initialized, which means that the event publisher is
@@ -229,7 +225,6 @@ public class ItemRegistryImpl extends AbstractRegistry<Item, String, ItemProvide
 
     private void removeFromGroupItems(Item item, List<String> groupItemNames) {
         for (String groupName : groupItemNames) {
-            if (groupName != null) {
             try {
                 if (getItem(groupName) instanceof GroupItem groupItem) {
                     groupItem.removeMember(item);
@@ -239,7 +234,6 @@ public class ItemRegistryImpl extends AbstractRegistry<Item, String, ItemProvide
             }
         }
     }
-    }
 
     @Override
     protected void onAddElement(Item element) throws IllegalArgumentException {

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/items/MetadataStateDescriptionFragmentProvider.java

@@ -125,7 +125,6 @@ public class MetadataStateDescriptionFragmentProvider implements StateDescriptio
 
     private BigDecimal getBigDecimal(Object value) {
         BigDecimal ret = null;
-        if (value != null) {
         if (value instanceof BigDecimal decimal) {
             ret = decimal;
         } else if (value instanceof String string) {
@@ -135,16 +134,14 @@ public class MetadataStateDescriptionFragmentProvider implements StateDescriptio
         } else if (value instanceof Number number) {
             ret = new BigDecimal(number.doubleValue());
         } else {
-                throw new ClassCastException("Not possible to coerce [" + value + "] from class " + value.getClass()
+            throw new ClassCastException(
-                        + " into a BigDecimal.");
+                    "Not possible to coerce [" + value + "] from class " + value.getClass() + " into a BigDecimal.");
-            }
         }
         return ret;
     }
 
     private Boolean getBoolean(Object value) {
         Boolean ret = null;
-        if (value != null) {
         if (value instanceof Boolean boolean1) {
             ret = boolean1;
         } else if (value instanceof String string) {
@@ -153,7 +150,6 @@ public class MetadataStateDescriptionFragmentProvider implements StateDescriptio
             throw new ClassCastException(
                     "Not possible to coerce [" + value + "] from class " + value.getClass() + " into a Boolean.");
         }
-        }
         return ret;
     }
 

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/scheduler/SchedulerImpl.java

@@ -200,7 +200,6 @@ public class SchedulerImpl implements Scheduler {
      */
     private static class ScheduledCompletableFutureRecurring<T> extends ScheduledCompletableFutureOnce<T> {
         private @Nullable volatile ScheduledCompletableFuture<T> scheduledPromise;
-        private @Nullable String identifier;
 
         public ScheduledCompletableFutureRecurring(@Nullable String identifier, ZonedDateTime scheduledTime) {
             super(identifier, scheduledTime);

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/types/StateDescriptionFragmentImpl.java

@@ -21,7 +21,6 @@ import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.core.types.StateDescription;
 import org.openhab.core.types.StateDescriptionFragment;
-import org.openhab.core.types.StateDescriptionFragmentBuilder;
 import org.openhab.core.types.StateOption;
 
 /**
@@ -62,7 +61,7 @@ public class StateDescriptionFragmentImpl implements StateDescriptionFragment {
      * @param pattern pattern to render the state
      * @param readOnly if the state can be changed by the system
      * @param options predefined list of options
-     * @deprecated use {@link StateDescriptionFragmentBuilder} instead.
+     * @deprecated use {@link org.openhab.core.types.StateDescriptionFragmentBuilder} instead.
      */
     @Deprecated
     public StateDescriptionFragmentImpl(@Nullable BigDecimal minimum, @Nullable BigDecimal maximum,
@@ -81,7 +80,7 @@ public class StateDescriptionFragmentImpl implements StateDescriptionFragment {
      * Note: State options will only be set if not empty.
      *
      * @param legacy the {@link StateDescription} to initialize from.
-     * @deprecated use {@link StateDescriptionFragmentBuilder} instead.
+     * @deprecated use {@link org.openhab.core.types.StateDescriptionFragmentBuilder} instead.
      */
     @Deprecated
     public StateDescriptionFragmentImpl(StateDescription legacy) {

bundles/org.openhab.core/src/main/java/org/openhab/core/items/GenericItem.java

@@ -294,7 +294,7 @@ public abstract class GenericItem implements ActiveItem {
         Set<StateChangeListener> clonedListeners = new CopyOnWriteArraySet<>(listeners);
         ExecutorService pool = ThreadPoolManager.getPool(ITEM_THREADPOOLNAME);
         try {
-            final boolean stateChanged = newState != null && !newState.equals(oldState);
+            final boolean stateChanged = !newState.equals(oldState);
             clonedListeners.forEach(listener -> pool.execute(() -> {
                 try {
                     listener.stateUpdated(GenericItem.this, newState);
@@ -372,7 +372,7 @@ public abstract class GenericItem implements ActiveItem {
     public int hashCode() {
         final int prime = 31;
         int result = 1;
-        result = prime * result + ((name == null) ? 0 : name.hashCode());
+        result = prime * result + name.hashCode();
         return result;
     }
 
@@ -388,11 +388,7 @@ public abstract class GenericItem implements ActiveItem {
             return false;
         }
         GenericItem other = (GenericItem) obj;
-        if (name == null) {
+        if (!name.equals(other.name)) {
-            if (other.name != null) {
-                return false;
-            }
-        } else if (!name.equals(other.name)) {
             return false;
         }
         return true;

bundles/org.openhab.core/src/main/java/org/openhab/core/items/GroupItem.java

@@ -223,7 +223,6 @@ public class GroupItem extends GenericItem implements StateChangeListener, Metad
      * @return the accepted data types of this group item
      */
     @Override
-    @SuppressWarnings("unchecked")
     public List<Class<? extends State>> getAcceptedDataTypes() {
         if (baseItem != null) {
             return baseItem.getAcceptedDataTypes();
@@ -249,7 +248,6 @@ public class GroupItem extends GenericItem implements StateChangeListener, Metad
      * @return the accepted command types of this group item
      */
     @Override
-    @SuppressWarnings("unchecked")
     public List<Class<? extends Command>> getAcceptedCommandTypes() {
         if (baseItem != null) {
             return baseItem.getAcceptedCommandTypes();
@@ -315,9 +313,9 @@ public class GroupItem extends GenericItem implements StateChangeListener, Metad
         sb.append("Type=");
         sb.append(getClass().getSimpleName());
         sb.append(", ");
-        if (getBaseItem() != null) {
+        if (getBaseItem() instanceof Item item) {
             sb.append("BaseType=");
-            sb.append(baseItem.getClass().getSimpleName());
+            sb.append(item.getClass().getSimpleName());
             sb.append(", ");
         }
         sb.append("Members=");

bundles/org.openhab.core/src/main/java/org/openhab/core/items/Item.java

@@ -19,15 +19,10 @@ import java.util.Set;
 import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.core.common.registry.Identifiable;
-import org.openhab.core.library.types.OnOffType;
-import org.openhab.core.library.types.PercentType;
 import org.openhab.core.types.Command;
 import org.openhab.core.types.CommandDescription;
-import org.openhab.core.types.CommandOption;
 import org.openhab.core.types.State;
 import org.openhab.core.types.StateDescription;
-import org.openhab.core.types.StateOption;
-import org.openhab.core.types.UnDefType;
 
 /**
  * <p>
@@ -75,14 +70,16 @@ public interface Item extends Identifiable<String> {
      * This method provides a list of all data types that can be used to update the item state
      *
      * <p>
-     * Imagine e.g. a dimmer device: It's status could be 0%, 10%, 50%, 100%, but also OFF or ON and maybe UNDEFINED. So
+     * Imagine e.g. a dimmer device: It's status could be 0%, 10%, 50%, 100%, but also OFF or ON and maybe
-     * the accepted data types would be in this case {@link PercentType}, {@link OnOffType} and {@link UnDefType}
+     * UNDEFINED. So the accepted data types would be in this case {@link org.openhab.core.library.types.PercentType},
+     * {@linkorg.openhab.core.library.types.OnOffType} and {@link org.openhab.core.types.UnDefType}
      *
      * <p>
      * The order of data types denotes the order of preference. So in case a state needs to be converted
      * in order to be accepted, it will be attempted to convert it to a type from top to bottom. Therefore
      * the type with the least information loss should be on top of the list - in the example above the
-     * {@link PercentType} carries more information than the {@link OnOffType}, hence it is listed first.
+     * {@link org.openhab.core.library.types.PercentType} carries more information than the
+     * {@linkorg.openhab.core.library.types.OnOffType}, hence it is listed first.
      *
      * @return a list of data types that can be used to update the item state
      */
@@ -93,8 +90,9 @@ public interface Item extends Identifiable<String> {
      * This method provides a list of all command types that can be used for this item
      *
      * <p>
-     * Imagine e.g. a dimmer device: You could ask it to dim to 0%, 10%, 50%, 100%, but also to turn OFF or ON. So the
+     * Imagine e.g. a dimmer device: You could ask it to dim to 0%, 10%, 50%, 100%, but also to turn OFF or ON.
-     * accepted command types would be in this case {@link PercentType}, {@link OnOffType}
+     * So the accepted command types would be in this case {@link org.openhab.core.library.types.PercentType},
+     * {@linkorg.openhab.core.library.types.OnOffType}
      *
      *
      * @return a list of all command types that can be used for this item
@@ -160,8 +158,8 @@ public interface Item extends Identifiable<String> {
 
     /**
      * Returns the {@link CommandDescription} for this item. In case no dedicated {@link CommandDescription} is
-     * provided the {@link StateOption}s from the {@link StateDescription} will be served as valid
+     * provided the {@link org.openhab.core.types.StateOption}s from the {@link StateDescription} will be served
-     * {@link CommandOption}s.
+     * as valid {@link org.openhab.core.types.CommandOption}s.
      *
      * @return the {@link CommandDescription} for the default locale (can be null).
      */
@@ -171,8 +169,9 @@ public interface Item extends Identifiable<String> {
 
     /**
      * Returns the {@link CommandDescription} for the given locale. In case no dedicated {@link CommandDescription} is
-     * provided the {@link StateOption}s from the {@link StateDescription} will be served as valid
+     * provided the {@link org.openhab.core.types.StateOption}s from the {@link StateDescription} will be served as
-     * {@link CommandOption}s.
+     * valid
+     * {@link org.openhab.core.types.CommandOption}s.
      *
      * @param locale locale (can be null)
      * @return command description (can be null)

bundles/org.openhab.core/src/main/java/org/openhab/core/items/ItemProvider.java

@@ -12,7 +12,6 @@
  */
 package org.openhab.core.items;
 
-import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.openhab.core.common.registry.Provider;
 
@@ -24,6 +23,6 @@ import org.openhab.core.common.registry.Provider;
  * @author Kai Kreuzer - Initial contribution
  */
 @NonNullByDefault
-public interface ItemProvider extends Provider<@NonNull Item> {
+public interface ItemProvider extends Provider<Item> {
 
 }

bundles/org.openhab.core/src/main/java/org/openhab/core/items/ManagedMetadataProvider.java

@@ -14,12 +14,11 @@ package org.openhab.core.items;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.openhab.core.common.registry.ManagedProvider;
-import org.openhab.core.storage.StorageService;
 
 /**
  * {@link ManagedMetadataProvider} is an OSGi service interface that allows to add or remove
  * metadata for items at runtime. Persistence of added metadata is handled by
- * a {@link StorageService}.
+ * a {@link org.openhab.core.storage.StorageService}.
  *
  * @author Kai Kreuzer - Initial contribution
  */

bundles/org.openhab.core/src/main/java/org/openhab/core/items/dto/ItemDTOMapper.java

@@ -46,13 +46,6 @@ public class ItemDTOMapper {
      * @return the item object
      */
     public static @Nullable Item map(ItemDTO itemDTO, ItemBuilderFactory itemBuilderFactory) {
-        if (itemDTO == null) {
-            throw new IllegalArgumentException("The argument 'itemDTO' must no be null.");
-        }
-        if (itemBuilderFactory == null) {
-            throw new IllegalArgumentException("The argument 'itemBuilderFactory' must no be null.");
-        }
-
         if (!ItemUtil.isValidItemName(itemDTO.name)) {
             throw new IllegalArgumentException("The item name '" + itemDTO.name + "' is invalid.");
         }

bundles/org.openhab.core/src/main/java/org/openhab/core/items/events/AbstractItemRegistryEvent.java

@@ -15,11 +15,11 @@ package org.openhab.core.items.events;
 import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.core.events.AbstractEvent;
-import org.openhab.core.items.ItemRegistry;
 import org.openhab.core.items.dto.ItemDTO;
 
 /**
- * Abstract implementation of an item registry event which will be posted by the {@link ItemRegistry} for added, removed
+ * Abstract implementation of an item registry event which will be posted by the
+ * {@link org.openhab.core.items.ItemRegistry} for added, removed
  * and updated items.
  *
  * @author Stefan Bußweiler - Initial contribution

bundles/org.openhab.core/src/main/java/org/openhab/core/library/items/NumberItem.java

@@ -16,7 +16,6 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Objects;
 
-import javax.measure.Dimension;
 import javax.measure.Quantity;
 import javax.measure.Unit;
 
@@ -130,9 +129,9 @@ public class NumberItem extends GenericItem implements MetadataAwareItem {
     }
 
     /**
-     * Returns the {@link Dimension} associated with this {@link NumberItem}, may be null.
+     * Returns the {@link javax.measure.Dimension} associated with this {@link NumberItem}, may be null.
      *
-     * @return the {@link Dimension} associated with this {@link NumberItem}, may be null.
+     * @return the {@link javax.measure.Dimension} associated with this {@link NumberItem}, may be null.
      */
     public @Nullable Class<? extends Quantity<?>> getDimension() {
         return dimension;

bundles/org.openhab.core/src/main/java/org/openhab/core/library/types/NextPreviousType.java

@@ -13,12 +13,11 @@
 package org.openhab.core.library.types;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
-import org.openhab.core.library.items.PlayerItem;
 import org.openhab.core.types.Command;
 import org.openhab.core.types.PrimitiveType;
 
 /**
- * This type is used by the {@link PlayerItem}.
+ * This type is used by the {@link org.openhab.core.library.items.PlayerItem}.
  *
  * @author Alex Tugarev - Initial contribution
  */

bundles/org.openhab.core/src/main/java/org/openhab/core/library/types/StringListType.java

@@ -13,7 +13,6 @@
 package org.openhab.core.library.types;
 
 import java.util.Arrays;
-import java.util.Formatter;
 import java.util.List;
 import java.util.stream.Collectors;
 
@@ -72,7 +71,7 @@ public class StringListType implements Command, State {
     /**
      * <p>
      * Formats the value of this type according to a pattern (@see
-     * {@link Formatter}). One single value of this type can be referenced
+     * {@link java.util.Formatter}). One single value of this type can be referenced
      * by the pattern using an index. The item order is defined by the natural
      * (alphabetical) order of their keys.
      *

bundles/org.openhab.core/src/main/java/org/openhab/core/net/CidrAddress.java

@@ -13,7 +13,6 @@
 package org.openhab.core.net;
 
 import java.net.InetAddress;
-import java.net.InterfaceAddress;
 import java.util.Objects;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
@@ -26,7 +25,7 @@ import org.eclipse.jdt.annotation.Nullable;
  * The toString() method will return a CIRDR representation, but the individual
  * address and prefix length can be accessed as well.
  *
- * Java has a class that exactly provides this {@link InterfaceAddress}, but unfortunately
+ * Java has a class that exactly provides this {@link java.net.InterfaceAddress}, but unfortunately
  * no public constructor exists.
  *
  * @author David Graeff - Initial contribution

bundles/org.openhab.core/src/main/java/org/openhab/core/net/NetUtil.java

@@ -582,9 +582,6 @@ public class NetUtil implements NetworkAddressService {
     }
 
     private boolean getConfigParameter(Map<String, Object> parameters, String parameter, boolean defaultValue) {
-        if (parameters == null) {
-            return defaultValue;
-        }
         Object value = parameters.get(parameter);
         if (value == null) {
             return defaultValue;

bundles/org.openhab.core/src/main/java/org/openhab/core/scheduler/CronAdjuster.java

@@ -16,7 +16,6 @@ import java.time.DayOfWeek;
 import java.time.temporal.ChronoField;
 import java.time.temporal.ChronoUnit;
 import java.time.temporal.Temporal;
-import java.time.temporal.TemporalAdjuster;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -31,7 +30,8 @@ import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.eclipse.jdt.annotation.Nullable;
 
 /**
- * This class creates a {@link TemporalAdjuster} that takes a temporal and adjust it to the next deadline based on a
+ * This class creates a {@link java.time.temporal.TemporalAdjuster} that takes a temporal and adjust it to the next
+ * deadline based on a
  * cron specification.
  *
  * @See http://www.cronmaker.com/

bundles/org.openhab.core/src/main/java/org/openhab/core/scheduler/Scheduler.java

@@ -17,7 +17,6 @@ import java.time.Instant;
 import java.time.temporal.TemporalAdjuster;
 import java.util.concurrent.Callable;
 import java.util.concurrent.CompletableFuture;
-import java.util.concurrent.TimeoutException;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.eclipse.jdt.annotation.Nullable;
@@ -79,7 +78,7 @@ public interface Scheduler {
     }
 
     /**
-     * Return a {@link ScheduledCompletableFuture} that fails with a {@link TimeoutException}
+     * Return a {@link ScheduledCompletableFuture} that fails with a {@link java.util.concurrent.TimeoutException}
      * when the given {@link CompletableFuture} is not resolved before the given timeout. If the
      * given {@link CompletableFuture} fails or is resolved before the timeout then the returned
      * {@link ScheduledCompletableFuture} will be treated accordingly. The cancellation does not influence

bundles/org.openhab.core/src/main/java/org/openhab/core/service/ReadyMarker.java

@@ -55,8 +55,8 @@ public final class ReadyMarker {
     public int hashCode() {
         final int prime = 31;
         int result = 1;
-        result = prime * result + ((identifier == null) ? 0 : identifier.hashCode());
+        result = prime * result + identifier.hashCode();
-        result = prime * result + ((type == null) ? 0 : type.hashCode());
+        result = prime * result + type.hashCode();
         return result;
     }
 
@@ -72,18 +72,10 @@ public final class ReadyMarker {
             return false;
         }
         ReadyMarker other = (ReadyMarker) obj;
-        if (identifier == null) {
+        if (!identifier.equals(other.identifier)) {
-            if (other.identifier != null) {
             return false;
         }
-        } else if (!identifier.equals(other.identifier)) {
+        if (!type.equals(other.type)) {
-            return false;
-        }
-        if (type == null) {
-            if (other.type != null) {
-                return false;
-            }
-        } else if (!type.equals(other.type)) {
             return false;
         }
         return true;

bundles/org.openhab.core/src/main/java/org/openhab/core/types/Type.java

@@ -12,8 +12,6 @@
  */
 package org.openhab.core.types;
 
-import java.util.Formatter;
-
 import org.eclipse.jdt.annotation.NonNullByDefault;
 
 /**
@@ -31,7 +29,7 @@ import org.eclipse.jdt.annotation.NonNullByDefault;
 public interface Type {
 
     /**
-     * Formats the value of this type according to a pattern (see {@link Formatter}).
+     * Formats the value of this type according to a pattern (see {@link java.util.Formatter}).
      *
      * @param pattern the pattern to use
      * @return the formatted string

bundles/org.openhab.core/src/main/java/org/openhab/core/util/ColorUtil.java

@@ -48,7 +48,6 @@ public class ColorUtil {
     private static final BigDecimal BIG_DECIMAL_60 = BigDecimal.valueOf(60);
     private static final BigDecimal BIG_DECIMAL_5 = BigDecimal.valueOf(5);
     private static final BigDecimal BIG_DECIMAL_3 = BigDecimal.valueOf(3);
-    private static final BigDecimal BIG_DECIMAL_2 = BigDecimal.valueOf(2);
     private static final BigDecimal BIG_DECIMAL_2_POINT_55 = new BigDecimal("2.55");
     private static final double[] CORM_COEFFICIENTS = { -0.00616793, 0.0893944, -0.5179722, 1.5317403, -2.4243787,
             1.925865, -0.471106 };

bundles/org.openhab.core/src/test/java/org/openhab/core/internal/i18n/I18nExceptionTest.java

@@ -24,13 +24,13 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
-import org.openhab.core.i18n.AbstractI18nException;
 import org.openhab.core.i18n.CommunicationException;
 import org.openhab.core.i18n.TranslationProvider;
 import org.osgi.framework.Bundle;
 
 /**
- * The {@link I18nExceptionTest} tests all the functionalities of the {@link AbstractI18nException} class.
+ * The {@link I18nExceptionTest} tests all the functionalities of the
+ * {@link org.openhab.core.i18n.AbstractI18nException} class.
  *
  * @author Laurent Garnier - Initial contribution
  */

bundles/org.openhab.core/src/test/java/org/openhab/core/util/UIDUtilsTest.java

@@ -19,10 +19,9 @@ import java.util.function.Consumer;
 import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.hamcrest.core.IsEqual;
 import org.junit.jupiter.api.Test;
-import org.openhab.core.common.AbstractUID;
 
 /**
- * Tests for {@link AbstractUID}.
+ * Tests for {@link org.openhab.core.common.AbstractUID}.
  *
  * @author Markus Rathgeb - Initial contribution
  */