Bump Error Prone version to 2.3.4 and fix new bug patterns

build.gradle

@@ -283,7 +283,7 @@ tasks.withType(Javadoc) {
 		testFixturesApi "org.mockito:mockito-core:3.3.3"
 		testImplementation 'com.jamesmurty.utils:java-xmlbuilder:1.2'
 
-		errorprone 'com.google.errorprone:error_prone_core:2.3.3'
+		errorprone 'com.google.errorprone:error_prone_core:2.3.4'
 		errorproneJavac('com.google.errorprone:javac:9+181-r4173-1')
 	}
 

smack-core/src/main/java/org/jivesoftware/smack/AbstractXMPPConnection.java

@@ -373,17 +373,6 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
 
     protected final AsyncButOrdered<StanzaListener> inOrderListeners = new AsyncButOrdered<>();
 
-    /**
-     * An executor which uses {@link #asyncGoLimited(Runnable)} to limit the number of asynchronously processed runnables
-     * per connection.
-     */
-    private final Executor limitedExcutor = new Executor() {
-        @Override
-        public void execute(Runnable runnable) {
-            asyncGoLimited(runnable);
-        }
-    };
-
     /**
      * The used host to establish the connection to
      */
@@ -1524,7 +1513,7 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
                         executorService = ASYNC_BUT_ORDERED.asExecutorFor(this);
                         break;
                     case async:
-                        executorService = limitedExcutor;
+                        executorService = this::asyncGoLimited;
                         break;
                     }
                     final IQRequestHandler finalIqRequestHandler = iqRequestHandler;

smack-core/src/main/java/org/jivesoftware/smack/util/TLSUtils.java

@@ -38,7 +38,6 @@ import java.util.Set;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
-import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.SSLPeerUnverifiedException;
 import javax.net.ssl.SSLSession;
@@ -143,14 +142,6 @@ public class TLSUtils {
         return builder;
     }
 
-    private static final HostnameVerifier DOES_NOT_VERIFY_VERIFIER = new HostnameVerifier() {
-        @Override
-        public boolean verify(String hostname, SSLSession session) {
-            // This verifier doesn't verify the hostname, it always returns true.
-            return true;
-        }
-    };
-
     /**
      * Disable the hostname verification of TLS certificates.
      * <p>
@@ -164,7 +155,9 @@ public class TLSUtils {
      * @return the given builder.
      */
     public static <B extends ConnectionConfiguration.Builder<B, ?>> B disableHostnameVerificationForTlsCertificates(B builder) {
-        builder.setHostnameVerifier(DOES_NOT_VERIFY_VERIFIER);
+        builder.setHostnameVerifier((hostname, session) -> {
+            return true;
+        });
         return builder;
     }
 

smack-core/src/test/java/org/jivesoftware/smack/util/DnsUtilTest.java

@@ -25,6 +25,7 @@ import org.junit.Test;
 
 public class DnsUtilTest {
 
+    @SuppressWarnings("UnnecessaryAnonymousClass")
     private static final SmackDaneProvider DNS_UTIL_TEST_DANE_PROVIDER = new SmackDaneProvider() {
         @Override
         public SmackDaneVerifier newInstance() {

smack-experimental/src/main/java/org/jivesoftware/smackx/fallback_indication/FallbackIndicationManager.java

@@ -25,7 +25,6 @@ import org.jivesoftware.smack.AsyncButOrdered;
 import org.jivesoftware.smack.ConnectionCreationListener;
 import org.jivesoftware.smack.Manager;
 import org.jivesoftware.smack.SmackException;
-import org.jivesoftware.smack.StanzaListener;
 import org.jivesoftware.smack.XMPPConnection;
 import org.jivesoftware.smack.XMPPConnectionRegistry;
 import org.jivesoftware.smack.XMPPException;
@@ -68,9 +67,7 @@ public final class FallbackIndicationManager extends Manager {
     private final StanzaFilter fallbackIndicationElementFilter = new AndFilter(StanzaTypeFilter.MESSAGE,
             new StanzaExtensionFilter(FallbackIndicationElement.ELEMENT, FallbackIndicationElement.NAMESPACE));
 
-    private final StanzaListener fallbackIndicationElementListener = new StanzaListener() {
+    private void fallbackIndicationElementListener(Stanza packet) {
-        @Override
-        public void processStanza(Stanza packet) {
         Message message = (Message) packet;
         FallbackIndicationElement indicator = FallbackIndicationElement.fromMessage(message);
         String body = message.getBody();
@@ -80,11 +77,10 @@ public final class FallbackIndicationManager extends Manager {
             }
         });
     }
-    };
 
     private FallbackIndicationManager(XMPPConnection connection) {
         super(connection);
-        connection.addAsyncStanzaListener(fallbackIndicationElementListener, fallbackIndicationElementFilter);
+        connection.addAsyncStanzaListener(this::fallbackIndicationElementListener, fallbackIndicationElementFilter);
         ServiceDiscoveryManager.getInstanceFor(connection).addFeature(FallbackIndicationElement.NAMESPACE);
     }
 

smack-experimental/src/main/java/org/jivesoftware/smackx/httpfileupload/HttpFileUploadManager.java

@@ -307,7 +307,9 @@ public final class HttpFileUploadManager extends Manager {
     public URL uploadFile(InputStream inputStream, String fileName, long fileSize, UploadProgressListener listener) throws XMPPErrorException, InterruptedException, SmackException, IOException {
         Objects.requireNonNull(inputStream, "Input Stream cannot be null");
         Objects.requireNonNull(fileName, "Filename Stream cannot be null");
-        Objects.requireNonNull(fileSize, "Filesize Stream cannot be null");
+        if (fileSize < 0) {
+            throw new IllegalArgumentException("File size cannot be negative");
+        }
         final Slot slot = requestSlot(fileName, fileSize, "application/octet-stream");
         upload(inputStream, fileSize, slot, listener);
         return slot.getGetUrl();

smack-experimental/src/main/java/org/jivesoftware/smackx/sid/StableUniqueStanzaIdManager.java

@@ -1,6 +1,6 @@
 /**
  *
- * Copyright 2018 Paul Schaub
+ * Copyright 2018 Paul Schaub, 2020 Florian Schmaus
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,10 +29,6 @@ import org.jivesoftware.smack.filter.NotFilter;
 import org.jivesoftware.smack.filter.StanzaExtensionFilter;
 import org.jivesoftware.smack.filter.StanzaFilter;
 import org.jivesoftware.smack.filter.ToTypeFilter;
-import org.jivesoftware.smack.packet.Message;
-import org.jivesoftware.smack.packet.MessageBuilder;
-import org.jivesoftware.smack.util.Consumer;
-import org.jivesoftware.smack.util.Predicate;
 
 import org.jivesoftware.smackx.disco.ServiceDiscoveryManager;
 import org.jivesoftware.smackx.sid.element.OriginIdElement;
@@ -62,14 +58,8 @@ public final class StableUniqueStanzaIdManager extends Manager {
     // Filter that filters for messages with an origin id
     private static final StanzaFilter ORIGIN_ID_FILTER = new StanzaExtensionFilter(OriginIdElement.ELEMENT, NAMESPACE);
 
-    // Listener for outgoing stanzas that adds origin-ids to outgoing stanzas.
-    private static final Consumer<MessageBuilder> ADD_ORIGIN_ID_INTERCEPTOR = mb -> OriginIdElement.addOriginId(mb);
-
     // We need a filter for outgoing messages that do not carry an origin-id already.
     private static final StanzaFilter ADD_ORIGIN_ID_FILTER = new AndFilter(OUTGOING_FILTER, new NotFilter(ORIGIN_ID_FILTER));
-    private static final Predicate<Message> ADD_ORIGIN_ID_PREDICATE = m -> {
-        return ADD_ORIGIN_ID_FILTER.accept(m);
-    };
 
     static {
         XMPPConnectionRegistry.addConnectionCreationListener(new ConnectionCreationListener() {
@@ -113,7 +103,7 @@ public final class StableUniqueStanzaIdManager extends Manager {
      * Start appending origin-id elements to outgoing stanzas and add the feature to disco.
      */
     public synchronized void enable() {
-        connection().addMessageInterceptor(ADD_ORIGIN_ID_INTERCEPTOR, ADD_ORIGIN_ID_PREDICATE);
+        connection().addMessageInterceptor(OriginIdElement::addTo, ADD_ORIGIN_ID_FILTER::accept);
         ServiceDiscoveryManager.getInstanceFor(connection()).addFeature(NAMESPACE);
     }
 
@@ -122,7 +112,7 @@ public final class StableUniqueStanzaIdManager extends Manager {
      */
     public synchronized void disable() {
         ServiceDiscoveryManager.getInstanceFor(connection()).removeFeature(NAMESPACE);
-        connection().removeMessageInterceptor(ADD_ORIGIN_ID_INTERCEPTOR);
+        connection().removeMessageInterceptor(OriginIdElement::addTo);
     }
 
     /**

smack-experimental/src/main/java/org/jivesoftware/smackx/sid/element/OriginIdElement.java

@@ -39,7 +39,7 @@ public class OriginIdElement extends StableAndUniqueIdElement {
      *
      * @param message message.
      * @return the added origin-id element.
-     * @deprecated use {@link #addOriginId(MessageBuilder)} instead.
+     * @deprecated use {@link #addTo(MessageBuilder)} instead.
      */
     @Deprecated
     // TODO: Remove in Smack 4.5.
@@ -57,7 +57,7 @@ public class OriginIdElement extends StableAndUniqueIdElement {
      * @param messageBuilder the message builder to add an origin ID to.
      * @return the added origin-id element.
      */
-    public static OriginIdElement addOriginId(MessageBuilder messageBuilder) {
+    public static OriginIdElement addTo(MessageBuilder messageBuilder) {
         OriginIdElement originId = new OriginIdElement();
         messageBuilder.addExtension(originId);
         // TODO: Find solution to have both the originIds stanzaId and a nice to look at incremental stanzaID.

smack-experimental/src/test/java/org/jivesoftware/smackx/sid/StableUniqueStanzaIdTest.java

@@ -78,7 +78,7 @@ public class StableUniqueStanzaIdTest extends SmackTestSuite {
         assertFalse(OriginIdElement.hasOriginId(message));
         assertFalse(StanzaIdElement.hasStanzaId(message));
 
-        OriginIdElement.addOriginId(messageBuilder);
+        OriginIdElement.addTo(messageBuilder);
 
         message = messageBuilder.build();
         assertTrue(OriginIdElement.hasOriginId(message));

smack-extensions/src/main/java/org/jivesoftware/smackx/caps/EntityCapsManager.java

@@ -54,7 +54,6 @@ import org.jivesoftware.smack.packet.PresenceBuilder;
 import org.jivesoftware.smack.packet.Stanza;
 import org.jivesoftware.smack.roster.AbstractPresenceEventListener;
 import org.jivesoftware.smack.roster.Roster;
-import org.jivesoftware.smack.util.Consumer;
 import org.jivesoftware.smack.util.StringUtils;
 import org.jivesoftware.smack.util.stringencoder.Base64;
 
@@ -312,11 +311,11 @@ public final class EntityCapsManager extends Manager {
     // Intercept presence packages and add caps data when intended.
     // XEP-0115 specifies that a client SHOULD include entity capabilities
     // with every presence notification it sends.
-    private final Consumer<PresenceBuilder> presenceInterceptor = presenceBuilder -> {
+    private void addCapsExtension(PresenceBuilder presenceBuilder) {
         CapsVersionAndHash capsVersionAndHash = getCapsVersionAndHash();
         CapsExtension caps = new CapsExtension(entityNode, capsVersionAndHash.version, capsVersionAndHash.hash);
         presenceBuilder.overrideExtension(caps);
-    };
+    }
 
     private EntityCapsManager(XMPPConnection connection) {
         super(connection);
@@ -402,7 +401,7 @@ public final class EntityCapsManager extends Manager {
     }
 
     public synchronized void enableEntityCaps() {
-        connection().addPresenceInterceptor(presenceInterceptor, p -> {
+        connection().addPresenceInterceptor(this::addCapsExtension, p -> {
             return PresenceTypeFilter.AVAILABLE.accept(p);
         });
 
@@ -415,7 +414,7 @@ public final class EntityCapsManager extends Manager {
         entityCapsEnabled = false;
         sdm.removeFeature(NAMESPACE);
 
-        connection().removePresenceInterceptor(presenceInterceptor);
+        connection().removePresenceInterceptor(this::addCapsExtension);
     }
 
     public boolean entityCapsEnabled() {

smack-extensions/src/main/java/org/jivesoftware/smackx/commands/AdHocCommandManager.java

@@ -517,7 +517,7 @@ public final class AdHocCommandManager extends Manager {
 
     private boolean sessionSweeperScheduled;
 
-    private final Runnable sessionSweeper = () -> {
+    private void sessionSweeper() {
         final long currentTime = System.currentTimeMillis();
         synchronized (this) {
             for (Iterator<Entry<String, LocalCommand>> it = executingCommands.entrySet().iterator(); it.hasNext();) {
@@ -553,7 +553,7 @@ public final class AdHocCommandManager extends Manager {
         }
 
         sessionSweeperScheduled = true;
-        schedule(sessionSweeper, 10, TimeUnit.SECONDS);
+        schedule(this::sessionSweeper, 10, TimeUnit.SECONDS);
     }
 
     /**

smack-extensions/src/main/java/org/jivesoftware/smackx/ping/PingManager.java

@@ -390,7 +390,7 @@ public final class PingManager extends Manager {
             int nextPingIn = pingInterval - delta;
             LOGGER.fine("Scheduling ServerPingTask in " + nextPingIn + " seconds (pingInterval="
                             + pingInterval + ", delta=" + delta + ")");
-            nextAutomaticPing = schedule(pingServerRunnable, nextPingIn, TimeUnit.SECONDS);
+            nextAutomaticPing = schedule(this::pingServerIfNecessary, nextPingIn, TimeUnit.SECONDS);
         }
     }
 
@@ -467,13 +467,4 @@ public final class PingManager extends Manager {
             }
         });
     }
-
-    private final Runnable pingServerRunnable = new Runnable() {
-        @Override
-        public void run() {
-            LOGGER.fine("ServerPingTask run()");
-            pingServerIfNecessary();
-        }
-    };
-
 }

smack-extensions/src/main/java/org/jivesoftware/smackx/receipts/DeliveryReceiptManager.java

@@ -1,6 +1,6 @@
 /**
  *
- * Copyright 2013-2014 Georg Lukas, 2015-2019 Florian Schmaus
+ * Copyright 2013-2014 Georg Lukas, 2015-2020 Florian Schmaus
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -38,11 +38,9 @@ import org.jivesoftware.smack.filter.StanzaExtensionFilter;
 import org.jivesoftware.smack.filter.StanzaFilter;
 import org.jivesoftware.smack.filter.StanzaTypeFilter;
 import org.jivesoftware.smack.packet.Message;
-import org.jivesoftware.smack.packet.MessageBuilder;
 import org.jivesoftware.smack.packet.Stanza;
 import org.jivesoftware.smack.packet.StanzaBuilder;
 import org.jivesoftware.smack.roster.Roster;
-import org.jivesoftware.smack.util.Consumer;
 import org.jivesoftware.smack.util.StringUtils;
 
 import org.jivesoftware.smackx.disco.ServiceDiscoveryManager;
@@ -273,8 +271,6 @@ public final class DeliveryReceiptManager extends Manager {
                     );
                    // @formatter:on
 
-    private static final Consumer<MessageBuilder> AUTO_ADD_DELIVERY_RECEIPT_REQUESTS_LISTENER = mb -> DeliveryReceiptRequest.addTo(mb);
-
     /**
      * Enables automatic requests of delivery receipts for outgoing messages of
      * {@link org.jivesoftware.smack.packet.Message.Type#normal}, {@link org.jivesoftware.smack.packet.Message.Type#chat} or {@link org.jivesoftware.smack.packet.Message.Type#headline}, and
@@ -284,7 +280,7 @@ public final class DeliveryReceiptManager extends Manager {
      * @see #dontAutoAddDeliveryReceiptRequests()
      */
     public void autoAddDeliveryReceiptRequests() {
-        connection().addMessageInterceptor(AUTO_ADD_DELIVERY_RECEIPT_REQUESTS_LISTENER, m -> {
+        connection().addMessageInterceptor(DeliveryReceiptRequest::addTo, m -> {
             return MESSAGES_TO_REQUEST_RECEIPTS_FOR.accept(m);
         });
     }
@@ -296,7 +292,7 @@ public final class DeliveryReceiptManager extends Manager {
      * @see #autoAddDeliveryReceiptRequests()
      */
     public void dontAutoAddDeliveryReceiptRequests() {
-        connection().removeMessageInterceptor(AUTO_ADD_DELIVERY_RECEIPT_REQUESTS_LISTENER);
+        connection().removeMessageInterceptor(DeliveryReceiptRequest::addTo);
     }
 
     /**

smack-im/src/main/java/org/jivesoftware/smack/roster/rosterstore/DirectoryRosterStore.java

@@ -1,6 +1,6 @@
 /**
  *
- * Copyright 2013-2015 the original author or authors
+ * Copyright 2013-2015 the original author or authors, 2020 Florian Schmaus
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,7 +17,6 @@
 package org.jivesoftware.smack.roster.rosterstore;
 
 import java.io.File;
-import java.io.FileFilter;
 import java.io.FileNotFoundException;
 import java.io.FileReader;
 import java.io.IOException;
@@ -56,16 +55,11 @@ public final class DirectoryRosterStore implements RosterStore {
     private static final String STORE_ID = "DEFAULT_ROSTER_STORE";
     private static final Logger LOGGER = Logger.getLogger(DirectoryRosterStore.class.getName());
 
-    private static final FileFilter rosterDirFilter = new FileFilter() {
+    private static boolean rosterDirFilter(File file) {
-
-        @Override
-        public boolean accept(File file) {
         String name = file.getName();
         return name.startsWith(ENTRY_PREFIX);
     }
 
-    };
-
     /**
      * @param baseDir TODO javadoc me please
      *            will be the directory where all roster entries are stored. One
@@ -122,7 +116,7 @@ public final class DirectoryRosterStore implements RosterStore {
     public List<Item> getEntries() {
         List<Item> entries = new ArrayList<>();
 
-        for (File file : fileDir.listFiles(rosterDirFilter)) {
+        for (File file : fileDir.listFiles(DirectoryRosterStore::rosterDirFilter)) {
             Item entry = readEntry(file);
             if (entry == null) {
                 // Roster directory store corrupt. Abort and signal this by returning null.
@@ -168,7 +162,7 @@ public final class DirectoryRosterStore implements RosterStore {
 
     @Override
     public boolean resetEntries(Collection<Item> items, String version) {
-        for (File file : fileDir.listFiles(rosterDirFilter)) {
+        for (File file : fileDir.listFiles(DirectoryRosterStore::rosterDirFilter)) {
             file.delete();
         }
         for (Item item : items) {

smack-integration-test/src/main/java/org/jivesoftware/smackx/chatstate/ChatStateIntegrationTest.java

@@ -21,7 +21,6 @@ import org.jivesoftware.smack.chat2.ChatManager;
 import org.jivesoftware.smack.packet.Message;
 
 import org.jivesoftware.smackx.chatstates.ChatState;
-import org.jivesoftware.smackx.chatstates.ChatStateListener;
 import org.jivesoftware.smackx.chatstates.ChatStateManager;
 
 import org.igniterealtime.smack.inttest.AbstractSmackIntegrationTest;
@@ -34,25 +33,19 @@ public class ChatStateIntegrationTest extends AbstractSmackIntegrationTest {
 
     // Listener for composing chat state
     private final SimpleResultSyncPoint composingSyncPoint = new SimpleResultSyncPoint();
-    private final ChatStateListener composingListener = new ChatStateListener() {
+    private void  composingListener(Chat chat, ChatState state, Message message) {
-        @Override
-        public void stateChanged(Chat chat, ChatState state, Message message) {
         if (state.equals(ChatState.composing)) {
             composingSyncPoint.signal();
         }
     }
-    };
 
     // Listener for active chat state
     private final SimpleResultSyncPoint activeSyncPoint = new SimpleResultSyncPoint();
-    private final ChatStateListener activeListener = new ChatStateListener() {
+    private void activeListener(Chat chat, ChatState state, Message message) {
-        @Override
-        public void stateChanged(Chat chat, ChatState state, Message message) {
         if (state.equals(ChatState.active)) {
             activeSyncPoint.signal();
         }
     }
-    };
 
 
     public ChatStateIntegrationTest(SmackIntegrationTestEnvironment environment) {
@@ -65,8 +58,8 @@ public class ChatStateIntegrationTest extends AbstractSmackIntegrationTest {
         ChatStateManager manTwo = ChatStateManager.getInstance(conTwo);
 
         // Add chatState listeners.
-        manTwo.addChatStateListener(composingListener);
+        manTwo.addChatStateListener(this::composingListener);
-        manTwo.addChatStateListener(activeListener);
+        manTwo.addChatStateListener(this::activeListener);
 
         Chat chatOne = ChatManager.getInstanceFor(conOne)
                 .chatWith(conTwo.getUser().asEntityBareJid());
@@ -86,7 +79,7 @@ public class ChatStateIntegrationTest extends AbstractSmackIntegrationTest {
     @AfterClass
     public void cleanup() {
         ChatStateManager manTwo = ChatStateManager.getInstance(conTwo);
-        manTwo.removeChatStateListener(composingListener);
+        manTwo.removeChatStateListener(this::composingListener);
-        manTwo.removeChatStateListener(activeListener);
+        manTwo.removeChatStateListener(this::activeListener);
     }
 }

smack-omemo/src/main/java/org/jivesoftware/smackx/omemo/OmemoManager.java

@@ -1,6 +1,6 @@
 /**
  *
- * Copyright 2017 Paul Schaub
+ * Copyright 2017 Paul Schaub, 2020 Florian Schmaus
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -37,17 +37,14 @@ import java.util.logging.Logger;
 import org.jivesoftware.smack.ConnectionListener;
 import org.jivesoftware.smack.Manager;
 import org.jivesoftware.smack.SmackException;
-import org.jivesoftware.smack.StanzaListener;
 import org.jivesoftware.smack.XMPPConnection;
 import org.jivesoftware.smack.XMPPException;
-import org.jivesoftware.smack.filter.StanzaFilter;
 import org.jivesoftware.smack.packet.ExtensionElement;
 import org.jivesoftware.smack.packet.Message;
 import org.jivesoftware.smack.packet.MessageBuilder;
 import org.jivesoftware.smack.packet.Stanza;
 import org.jivesoftware.smack.util.Async;
 
-import org.jivesoftware.smackx.carbons.CarbonCopyReceivedListener;
 import org.jivesoftware.smackx.carbons.CarbonManager;
 import org.jivesoftware.smackx.carbons.packet.CarbonExtension;
 import org.jivesoftware.smackx.disco.ServiceDiscoveryManager;
@@ -74,7 +71,6 @@ import org.jivesoftware.smackx.omemo.trust.OmemoFingerprint;
 import org.jivesoftware.smackx.omemo.trust.OmemoTrustCallback;
 import org.jivesoftware.smackx.omemo.trust.TrustState;
 import org.jivesoftware.smackx.omemo.util.MessageOrOmemoMessage;
-import org.jivesoftware.smackx.pep.PepListener;
 import org.jivesoftware.smackx.pep.PepManager;
 import org.jivesoftware.smackx.pubsub.EventElement;
 import org.jivesoftware.smackx.pubsub.ItemsExtension;
@@ -897,23 +893,23 @@ public final class OmemoManager extends Manager {
         CarbonManager carbonManager = CarbonManager.getInstanceFor(connection());
 
         // Remove listeners to avoid them getting added twice
-        connection().removeAsyncStanzaListener(internalOmemoMessageStanzaListener);
+        connection().removeAsyncStanzaListener(this::internalOmemoMessageStanzaListener);
-        carbonManager.removeCarbonCopyReceivedListener(internalOmemoCarbonCopyListener);
+        carbonManager.removeCarbonCopyReceivedListener(this::internalOmemoCarbonCopyListener);
-        pepManager.removePepListener(deviceListUpdateListener);
+        pepManager.removePepListener(this::deviceListUpdateListener);
 
         // Add listeners
-        pepManager.addPepListener(deviceListUpdateListener);
+        pepManager.addPepListener(this::deviceListUpdateListener);
-        connection().addAsyncStanzaListener(internalOmemoMessageStanzaListener, omemoMessageStanzaFilter);
+        connection().addAsyncStanzaListener(this::internalOmemoMessageStanzaListener, OmemoManager::isOmemoMessage);
-        carbonManager.addCarbonCopyReceivedListener(internalOmemoCarbonCopyListener);
+        carbonManager.addCarbonCopyReceivedListener(this::internalOmemoCarbonCopyListener);
     }
 
     /**
      * Remove active stanza listeners needed for OMEMO.
      */
     public void stopStanzaAndPEPListeners() {
-        PepManager.getInstanceFor(connection()).removePepListener(deviceListUpdateListener);
+        PepManager.getInstanceFor(connection()).removePepListener(this::deviceListUpdateListener);
-        connection().removeAsyncStanzaListener(internalOmemoMessageStanzaListener);
+        connection().removeAsyncStanzaListener(this::internalOmemoMessageStanzaListener);
-        CarbonManager.getInstanceFor(connection()).removeCarbonCopyReceivedListener(internalOmemoCarbonCopyListener);
+        CarbonManager.getInstanceFor(connection()).removeCarbonCopyReceivedListener(this::internalOmemoCarbonCopyListener);
     }
 
     /**
@@ -961,10 +957,7 @@ public final class OmemoManager extends Manager {
     /**
      * StanzaListener that listens for incoming Stanzas which contain OMEMO elements.
      */
-    private final StanzaListener internalOmemoMessageStanzaListener = new StanzaListener() {
+    private void internalOmemoMessageStanzaListener(final Stanza packet) {
-
-        @Override
-        public void processStanza(final Stanza packet) {
         Async.go(new Runnable() {
             @Override
             public void run() {
@@ -977,20 +970,17 @@ public final class OmemoManager extends Manager {
             }
         });
     }
-    };
 
     /**
      * CarbonCopyListener that listens for incoming carbon copies which contain OMEMO elements.
      */
-    private final CarbonCopyReceivedListener internalOmemoCarbonCopyListener = new CarbonCopyReceivedListener() {
+    private void internalOmemoCarbonCopyListener(final CarbonExtension.Direction direction,
-        @Override
-        public void onCarbonCopyReceived(final CarbonExtension.Direction direction,
                     final Message carbonCopy,
                     final Message wrappingMessage) {
         Async.go(new Runnable() {
             @Override
             public void run() {
-                    if (omemoMessageStanzaFilter.accept(carbonCopy)) {
+                if (isOmemoMessage(carbonCopy)) {
                     try {
                         getOmemoService().onOmemoCarbonCopyReceived(direction, carbonCopy, wrappingMessage,
                                 new LoggedInOmemoManager(OmemoManager.this));
@@ -1001,15 +991,11 @@ public final class OmemoManager extends Manager {
             }
         });
     }
-    };
 
     /**
      * PEPListener that listens for OMEMO deviceList updates.
      */
-    private final PepListener deviceListUpdateListener = new PepListener() {
+    private void deviceListUpdateListener(EntityBareJid from, EventElement event, Message message) {
-        @Override
-        public void eventReceived(EntityBareJid from, EventElement event, Message message) {
-
         // Unknown sender, no more work to do.
         if (from == null) {
             // TODO: This DOES happen for some reason. Figure out when...
@@ -1071,17 +1057,13 @@ public final class OmemoManager extends Manager {
             }
         }
     }
-    };
 
     /**
      * StanzaFilter that filters messages containing a OMEMO element.
      */
-    private final StanzaFilter omemoMessageStanzaFilter = new StanzaFilter() {
+    private static boolean isOmemoMessage(Stanza stanza) {
-        @Override
-        public boolean accept(Stanza stanza) {
         return stanza instanceof Message && OmemoManager.stanzaContainsOmemoElement(stanza);
     }
-    };
 
     /**
      * Guard class which ensures that the wrapped OmemoManager knows its BareJid.

smack-openpgp/src/main/java/org/jivesoftware/smackx/ox/OpenPgpManager.java

@@ -1,6 +1,6 @@
 /**
  *
- * Copyright 2017-2019 Florian Schmaus, 2018 Paul Schaub.
+ * Copyright 2017-2020 Florian Schmaus, 2018 Paul Schaub.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -39,7 +39,6 @@ import org.jivesoftware.smack.XMPPConnection;
 import org.jivesoftware.smack.XMPPException;
 import org.jivesoftware.smack.chat2.Chat;
 import org.jivesoftware.smack.chat2.ChatManager;
-import org.jivesoftware.smack.chat2.IncomingChatMessageListener;
 import org.jivesoftware.smack.packet.Message;
 import org.jivesoftware.smack.util.Async;
 import org.jivesoftware.smack.util.stringencoder.Base64;
@@ -180,7 +179,7 @@ public final class OpenPgpManager extends Manager {
      */
     private OpenPgpManager(XMPPConnection connection) {
         super(connection);
-        ChatManager.getInstanceFor(connection).addIncomingListener(incomingOpenPgpMessageListener);
+        ChatManager.getInstanceFor(connection).addIncomingListener(this::incomingChatMessageListener);
         pepManager = PepManager.getInstanceFor(connection);
     }
 
@@ -279,7 +278,7 @@ public final class OpenPgpManager extends Manager {
         publishPublicKey(pepManager, pubkeyElement, primaryFingerprint);
 
         // Subscribe to public key changes
-        PepManager.getInstanceFor(connection()).addPepListener(metadataListener);
+        PepManager.getInstanceFor(connection()).addPepListener(this::metadataListener);
         ServiceDiscoveryManager.getInstanceFor(connection())
                 .addFeature(PEP_NODE_PUBLIC_KEYS_NOTIFY);
     }
@@ -381,7 +380,7 @@ public final class OpenPgpManager extends Manager {
      * Remove the metadata listener. This method is mainly used in tests.
      */
     public void stopMetadataListener() {
-        PepManager.getInstanceFor(connection()).removePepListener(metadataListener);
+        PepManager.getInstanceFor(connection()).removePepListener(this::metadataListener);
     }
 
     /**
@@ -502,9 +501,7 @@ public final class OpenPgpManager extends Manager {
      *
      * @see <a href="https://xmpp.org/extensions/xep-0373.html#pubsub-notifications">XEP-0373 §4.4</a>
      */
-    private final PepListener metadataListener = new PepListener() {
+    private void metadataListener(final EntityBareJid from, final EventElement event, final Message message) {
-        @Override
-        public void eventReceived(final EntityBareJid from, final EventElement event, final Message message) {
         if (PEP_NODE_PUBLIC_KEYS.equals(event.getEvent().getNode())) {
             final BareJid contact = from.asBareJid();
             LOGGER.log(Level.INFO, "Received OpenPGP metadata update from " + contact);
@@ -520,7 +517,6 @@ public final class OpenPgpManager extends Manager {
             }, "ProcessOXMetadata");
         }
     }
-    };
 
     private void processPublicKeysListElement(BareJid contact, PublicKeysListElement listElement) {
         OpenPgpContact openPgpContact = getOpenPgpContact(contact.asEntityBareJidIfPossible());
@@ -548,10 +544,7 @@ public final class OpenPgpManager extends Manager {
         return provider.decryptAndOrVerify(element, getOpenPgpSelf(), sender);
     }
 
-    private final IncomingChatMessageListener incomingOpenPgpMessageListener =
+    private void incomingChatMessageListener(final EntityBareJid from, final Message message, Chat chat) {
-            new IncomingChatMessageListener() {
-                @Override
-                public void newIncomingMessage(final EntityBareJid from, final Message message, Chat chat) {
         Async.go(new Runnable() {
             @Override
             public void run() {
@@ -578,7 +571,8 @@ public final class OpenPgpManager extends Manager {
 
                 if (contentElement instanceof SigncryptElement) {
                     for (SigncryptElementReceivedListener l : signcryptElementReceivedListeners) {
-                                    l.signcryptElementReceived(contact, message, (SigncryptElement) contentElement, decrypted.getMetadata());
+                        l.signcryptElementReceived(contact, message, (SigncryptElement) contentElement,
+                                        decrypted.getMetadata());
                     }
                     return;
                 }
@@ -592,7 +586,8 @@ public final class OpenPgpManager extends Manager {
 
                 if (contentElement instanceof CryptElement) {
                     for (CryptElementReceivedListener l : cryptElementReceivedListeners) {
-                                    l.cryptElementReceived(contact, message, (CryptElement) contentElement, decrypted.getMetadata());
+                        l.cryptElementReceived(contact, message, (CryptElement) contentElement,
+                                        decrypted.getMetadata());
                     }
                     return;
                 }
@@ -603,7 +598,6 @@ public final class OpenPgpManager extends Manager {
             }
         });
     }
-            };
 
     /**
      * Create a {@link PubkeyElement} which contains the OpenPGP public key of {@code owner} which belongs to

smack-openpgp/src/main/java/org/jivesoftware/smackx/ox_im/OXInstantMessagingManager.java

@@ -44,7 +44,6 @@ import org.jivesoftware.smackx.ox.crypto.OpenPgpElementAndMetadata;
 import org.jivesoftware.smackx.ox.element.OpenPgpContentElement;
 import org.jivesoftware.smackx.ox.element.OpenPgpElement;
 import org.jivesoftware.smackx.ox.element.SigncryptElement;
-import org.jivesoftware.smackx.ox.listener.SigncryptElementReceivedListener;
 
 import org.bouncycastle.openpgp.PGPException;
 import org.jxmpp.jid.BareJid;
@@ -127,7 +126,7 @@ public final class OXInstantMessagingManager extends Manager {
     private OXInstantMessagingManager(final XMPPConnection connection) {
         super(connection);
         openPgpManager = OpenPgpManager.getInstanceFor(connection);
-        openPgpManager.registerSigncryptReceivedListener(signcryptElementReceivedListener);
+        openPgpManager.registerSigncryptReceivedListener(this::signcryptElementReceivedListener);
         announceSupportForOxInstantMessaging();
     }
 
@@ -358,12 +357,9 @@ public final class OXInstantMessagingManager extends Manager {
         message.setBody("This message is encrypted using XEP-0374: OpenPGP for XMPP: Instant Messaging.");
     }
 
-    private final SigncryptElementReceivedListener signcryptElementReceivedListener = new SigncryptElementReceivedListener() {
+    private void signcryptElementReceivedListener(OpenPgpContact contact, Message originalMessage, SigncryptElement signcryptElement, OpenPgpMetadata metadata) {
-        @Override
-        public void signcryptElementReceived(OpenPgpContact contact, Message originalMessage, SigncryptElement signcryptElement, OpenPgpMetadata metadata) {
         for (OxMessageListener listener : oxMessageListeners) {
             listener.newIncomingOxMessage(contact, originalMessage, signcryptElement, metadata);
         }
     }
-    };
 }

smack-tcp/src/main/java/org/jivesoftware/smack/tcp/XmppTcpTransportModule.java

@@ -21,6 +21,7 @@ import java.net.InetSocketAddress;
 import java.nio.Buffer;
 import java.nio.ByteBuffer;
 import java.nio.channels.ClosedChannelException;
+import java.nio.channels.SelectableChannel;
 import java.nio.channels.SelectionKey;
 import java.nio.channels.SocketChannel;
 import java.security.KeyManagementException;
@@ -61,7 +62,6 @@ import org.jivesoftware.smack.SmackException.SecurityRequiredByServerException;
 import org.jivesoftware.smack.SmackException.SmackWrappedException;
 import org.jivesoftware.smack.SmackFuture;
 import org.jivesoftware.smack.SmackFuture.InternalSmackFuture;
-import org.jivesoftware.smack.SmackReactor.ChannelSelectedCallback;
 import org.jivesoftware.smack.SmackReactor.SelectionKeyAttachment;
 import org.jivesoftware.smack.XMPPException.FailedNonzaException;
 import org.jivesoftware.smack.XmppInputOutputFilter;
@@ -280,8 +280,7 @@ public class XmppTcpTransportModule extends ModularXmppClientToServerConnectionM
         }
     };
 
-    private final ChannelSelectedCallback channelSelectedCallback =
+    private void onChannelSelected(SelectableChannel selectedChannel, SelectionKey selectedSelectionKey) {
-                    (selectedChannel, selectedSelectionKey) -> {
         assert selectionKey == null || selectionKey == selectedSelectionKey;
         SocketChannel selectedSocketChannel = (SocketChannel) selectedChannel;
         // We are *always* interested in OP_READ.
@@ -488,7 +487,6 @@ public class XmppTcpTransportModule extends ModularXmppClientToServerConnectionM
                             + " for " + this + ". This probably means that the TCP connection was terminated.");
                     // According to the socket channel javadoc section about "asynchronous reads" a socket channel's
                     // read() may return -1 if the input side of a socket is shut down.
-
                      // Note that we do not call notifyConnectionError() here because the connection may be
                     // cleanly shutdown which would also cause read() to return '-1. I assume that this socket
                     // will be selected again, on which read() would throw an IOException, which will be catched
@@ -567,7 +565,7 @@ public class XmppTcpTransportModule extends ModularXmppClientToServerConnectionM
         }
 
         connectionInternal.setInterestOps(selectionKey, newInterestedOps);
-            };
+    }
 
     private void handleReadWriteIoException(IOException e) {
         if (e instanceof ClosedChannelException && !tcpNioTransport.isConnected()) {
@@ -677,7 +675,7 @@ public class XmppTcpTransportModule extends ModularXmppClientToServerConnectionM
         }
 
         @Override
-        public Stats getStats() {
+        public XmppTcpTransportModule.Stats getStats() {
             return XmppTcpTransportModule.this.getStats();
         }
 
@@ -774,7 +772,7 @@ public class XmppTcpTransportModule extends ModularXmppClientToServerConnectionM
             remoteAddress = (InetSocketAddress) socketChannel.socket().getRemoteSocketAddress();
 
             selectionKey = connectionInternal.registerWithSelector(socketChannel, SelectionKey.OP_READ,
-                            channelSelectedCallback);
+                            XmppTcpTransportModule.this::onChannelSelected);
             selectionKeyAttachment = (SelectionKeyAttachment) selectionKey.attachment();
 
             connectionInternal.setTransport(tcpNioTransport);
@@ -1316,7 +1314,7 @@ public class XmppTcpTransportModule extends ModularXmppClientToServerConnectionM
                 pendingOutputFilterData = true;
             }
 
-            channelSelectedCallback.onChannelSelected(channel, key);
+            onChannelSelected(channel, key);
         } finally {
             channelSelectedCallbackLock.unlock();
         }
@@ -1347,7 +1345,7 @@ public class XmppTcpTransportModule extends ModularXmppClientToServerConnectionM
         return CollectionUtil.removeUntil(buffers, b -> b.hasRemaining());
     }
 
-    public Stats getStats() {
+    public XmppTcpTransportModule.Stats getStats() {
         return new Stats(this);
     }