Some Small Code Improvements

dbus-java-core/src/main/java/org/freedesktop/dbus/RemoteInvocationHandler.java

@@ -30,8 +30,8 @@ public class RemoteInvocationHandler implements InvocationHandler {
     private static final Logger LOGGER = LoggerFactory.getLogger(RemoteInvocationHandler.class);
 
     // CHECKSTYLE:OFF
-    AbstractConnection conn;
-    RemoteObject       remote;
+    private final AbstractConnection conn;
+    private final RemoteObject       remote;
     // CHECKSTYLE:ON
 
     public RemoteInvocationHandler(AbstractConnection _conn, RemoteObject _remote) {

dbus-java-core/src/main/java/org/freedesktop/dbus/StructHelper.java

@@ -109,7 +109,7 @@ public static <T extends Struct> void convertToStructCollection(Collection<Objec
             if (constructorArgClasses.length != object.length) {
                 throw new IllegalArgumentException("Struct length does not match argument length");
             }
-            T x = createStruct(constructorArgClasses, (Object) object, _structType);
+            T x = createStruct(constructorArgClasses, object, _structType);
             _result.add(x);
         }
 

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/BusAddress.java

@@ -49,7 +49,7 @@ public static BusAddress of(String _address) {
             throw new InvalidBusAddressException("Bus address is blank");
         }
 
-        BusAddress busAddress = new BusAddress((BusAddress) null);
+        BusAddress busAddress = new BusAddress(null);
 
         LOGGER.trace("Parsing bus address: {}", _address);
 

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/SASL.java

@@ -20,7 +20,6 @@
 import java.io.*;
 import java.net.SocketException;
 import java.nio.ByteBuffer;
-import java.nio.channels.NetworkChannel;
 import java.nio.channels.SocketChannel;
 import java.nio.charset.Charset;
 import java.nio.file.Files;
@@ -600,14 +599,14 @@ public boolean auth(SocketChannel _sock, AbstractTransport _transport) throws IO
                 switch (state) {
                     case INITIAL_STATE:
                         ByteBuffer buf = ByteBuffer.allocate(1);
-                        if (_sock instanceof NetworkChannel) {
+                        if (_sock != null) {
                             _sock.read(buf); // 0
                             state = SaslAuthState.WAIT_AUTH;
                         } else {
                             try {
                                 int kuid = -1;
                                 if (_transport instanceof AbstractUnixTransport aut) {
-                                    kuid = aut.getUid(_sock);
+                                    kuid = aut.getUid(null);
                                 }
                                 if (kuid >= 0) {
                                     kernelUid = stupidlyEncode("" + kuid);

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/base/DBusBoundPropertyHandler.java

@@ -28,7 +28,6 @@
 import java.util.*;
 import java.util.Map.Entry;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.stream.Collectors;
 
 /**
  * Abstract class containing methods for handling DBus properties and {@link DBusBoundProperty} annotation. <br>
@@ -125,9 +124,9 @@ protected PropHandled handleGetAll(ExportedObject _exportObject, final MethodCal
                             Object val = invokeMethod(_methodCall, propMeth, object);
 
                             // when the value is a collection, array or map, wrap them in a proper variant type
-                            if (val != null && val.getClass().isArray() || Collection.class.isInstance(val) || Map.class.isInstance(val)) {
+                            if (val != null && val.getClass().isArray() || val instanceof Collection || val instanceof Map) {
                                 String[] dataType = Marshalling.getDBusType(propEn.getValue().getGenericReturnType());
-                                String dataTypeStr = Arrays.stream(dataType).collect(Collectors.joining());
+                                String dataTypeStr = String.join("", dataType);
                                 getLogger().trace("Creating embedded Array/Collection/Map of type {}", dataTypeStr);
                                 val = new Variant<>(val, dataTypeStr);
                             }

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/base/FallbackContainer.java

@@ -30,7 +30,6 @@ public synchronized void remove(String _path) {
     }
 
     public synchronized ExportedObject get(String _path) {
-        int best = 0;
         ExportedObject bestobject = null;
         String[] pathel = _path.split("/");
         for (Map.Entry<String[], ExportedObject> entry : fallbacks.entrySet()) {
@@ -48,7 +47,7 @@ public synchronized ExportedObject get(String _path) {
                     break;
                 }
             }
-            if (i > 0 && i == fbpath.length && i > best) {
+            if (i > 0 && i == fbpath.length) {
                 bestobject = entry.getValue();
             }
             logger.trace("Matches {} bestobject now {}", i, bestobject);

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/base/IncomingMessageThread.java

@@ -32,14 +32,11 @@ public void terminate() {
     @Override
     public void run() {
 
-        Message msg;
         while (!terminate) {
-            msg = null;
-
             // read from the wire
             try {
                 // this blocks on outgoing being non-empty or a message being available.
-                msg = connection.readIncoming();
+                Message msg = connection.readIncoming();
                 if (msg != null) {
                     logger.trace("Read message from {}: {}", connection.getTransport(), msg);
 

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/impl/DBusConnection.java

@@ -132,15 +132,11 @@ public void register() throws DBusException {
     }
 
     /**
-     * Do some action with the currently registered names in a synchronized manor.
+     * Do some action with the currently registered names in a synchronized manner.
      *
-     * @param _exClz exception type which may be thrown
      * @param _action action to execute
-     * @param <X> type of exception
      *
      * @return whatever the action returns
-     *
-     * @throws X thrown when action throws
      */
     private <T> T doWithBusNamesAndReturn(Function<List<String>, T> _action) {
         if (_action == null) {
@@ -152,13 +148,9 @@ private <T> T doWithBusNamesAndReturn(Function<List<String>, T> _action) {
     }
 
     /**
-     * Do some action with the currently registered names in a synchronized manor.
+     * Do some action with the currently registered names in a synchronized manner.
      *
-     * @param _exClz exception type which may be thrown
      * @param _action action to execute
-     * @param <X> type of exception
-     *
-     * @throws X thrown when action throws
      */
     private void doWithBusNames(Consumer<List<String>> _action) {
         doWithBusNamesAndReturn(bn -> {
@@ -302,7 +294,7 @@ public void requestBusName(String _busname) throws DBusException {
      * @return unique name
      */
     public String getUniqueName() {
-        return doWithBusNamesAndReturn(bn -> bn.getFirst());
+        return doWithBusNamesAndReturn(List::getFirst);
     }
 
     /**
@@ -311,11 +303,7 @@ public String getUniqueName() {
      * @return connection names
      */
     public String[] getNames() {
-        return doWithBusNamesAndReturn(bn -> {
-            Set<String> names = new TreeSet<>();
-            names.addAll(bn);
-            return names;
-        }).toArray(String[]::new);
+        return doWithBusNamesAndReturn(TreeSet::new).toArray(String[]::new);
     }
 
     @Override
@@ -514,7 +502,7 @@ public <T extends DBusSignal> AutoCloseable addSigHandler(DBusMatchRule _rule, D
             try {
                 dbus.AddMatch(_rule.toString());
             } catch (DBusExecutionException _ex) {
-                logger.debug("Cannot add match rule: " + _rule.toString(), _ex);
+                logger.debug("Cannot add match rule: {}", _rule, _ex);
                 throw new DBusException("Cannot add match rule.", _ex);
             }
         }

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/impl/DBusConnectionBuilder.java

@@ -121,23 +121,21 @@ private static BusAddress validateTransportAddress(BusAddress _address) {
             throw new IllegalArgumentException("No transports found to connect to DBus. Please add at least one transport provider to your classpath");
         }
 
-        BusAddress address = _address;
-
         // no unix transport but address wants to use a unix socket
         if (!TransportBuilder.getRegisteredBusTypes().contains("UNIX")
-                && address != null
-                && address.isBusType("UNIX")) {
+                && _address != null
+                && _address.isBusType("UNIX")) {
             throw new AddressResolvingException("No transports found to handle UNIX socket connections. Please add a unix-socket transport provider to your classpath");
         }
 
         // no tcp transport but TCP address given
         if (!TransportBuilder.getRegisteredBusTypes().contains("TCP")
-                && address != null
-                && address.isBusType("TCP")) {
+                && _address != null
+                && _address.isBusType("TCP")) {
             throw new AddressResolvingException("No transports found to handle TCP connections. Please add a TCP transport provider to your classpath");
         }
 
-        return address;
+        return _address;
 
     }
 

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/impl/IRemoteObjectGetter.java

@@ -64,7 +64,7 @@ default <I extends DBusInterface> I getPeerRemoteObject(String _busname, DBusPat
      * happens, try specifying the interface explicitly.
      *
      * @param _busname
-     *            The bus name to connect to. Usually a well known bus name name in dot-notation (such as
+     *            The bus name to connect to. Usually a well known bus name in dot-notation (such as
      *            "org.freedesktop.local") or may be a DBus address such as ":1-16".
      * @param _objectpath
      *            The path on which the process is exporting the object.

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/transports/AbstractTransport.java

@@ -266,7 +266,6 @@ private void authenticate(SocketChannel _sock) throws IOException {
      * The default implementation does not support file descriptor passing!
      *
      * @param _socket socket to use
-     * @param _messageFactory message factory
      * @return TransportConnection with configured socket channel, reader and writer
      */
     private TransportConnection createInputOutput(SocketChannel _socket) {

dbus-java-core/src/main/java/org/freedesktop/dbus/connections/transports/TransportBuilder.java

@@ -120,7 +120,6 @@ public static TransportBuilder create() {
      * @param _address address, never null
      *
      * @return new {@link TransportBuilder}
-     * @throws DBusException if invalid address provided
      */
     public static TransportBuilder create(BusAddress _address) {
         Objects.requireNonNull(_address, "BusAddress required");

dbus-java-core/src/main/java/org/freedesktop/dbus/matchrules/DBusMatchRule.java

@@ -23,7 +23,7 @@ public final class DBusMatchRule {
     private final Map<MatchRuleField, String> fields = new TreeMap<>();
     private final Map<MatchRuleField, Map<Integer, String>> multiValueFields = new TreeMap<>();
 
-    protected DBusMatchRule(Map<MatchRuleField, String> _values, Map<MatchRuleField, Map<Integer, String>> _multiValues) {
+    DBusMatchRule(Map<MatchRuleField, String> _values, Map<MatchRuleField, Map<Integer, String>> _multiValues) {
         fields.putAll(Objects.requireNonNull(_values, "Values required"));
         if (_multiValues != null) {
             multiValueFields.putAll(_multiValues);

dbus-java-core/src/main/java/org/freedesktop/dbus/matchrules/DBusMatchRuleBuilder.java

@@ -126,7 +126,7 @@ public DBusMatchRuleBuilder withMember(String _member) {
      */
     public DBusMatchRuleBuilder withType(String _type) {
         if (Stream.of(MessageTypes.values())
-            .map(e -> e.getMatchRuleName())
+            .map(MessageTypes::getMatchRuleName)
             .noneMatch(e -> e.equals(_type))) {
             throw new IllegalArgumentException(_type + " is not a valid message type");
         }

dbus-java-core/src/main/java/org/freedesktop/dbus/matchrules/MatchRuleField.java

@@ -2,23 +2,23 @@
 
 import org.freedesktop.dbus.messages.Message;
 import org.freedesktop.dbus.messages.constants.MessageTypes;
-import org.freedesktop.dbus.utils.Util;
 
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Objects;
 import java.util.function.BiPredicate;
 
 public enum MatchRuleField {
-    TYPE((m, s) -> Util.strEquals(MessageTypes.getRuleNameById(m.getType()), s), null),
-    SENDER((m, s) -> Util.strEquals(m.getSource(), s), null),
-    INTERFACE((m, s) -> Util.strEquals(m.getInterface(), s), null),
-    MEMBER((m, s) -> Util.strEquals(m.getName(), s), null),
-    PATH((m, s) -> Util.strEquals(m.getPath(), s), null),
+    TYPE((m, s) -> Objects.equals(MessageTypes.getRuleNameById(m.getType()), s), null),
+    SENDER((m, s) -> Objects.equals(m.getSource(), s), null),
+    INTERFACE((m, s) -> Objects.equals(m.getInterface(), s), null),
+    MEMBER((m, s) -> Objects.equals(m.getName(), s), null),
+    PATH((m, s) -> Objects.equals(m.getPath(), s), null),
     PATH_NAMESPACE((m, s) -> MatchRuleMatcher.matchPathNamespace(m.getPath(), s), null),
-    DESTINATION((m, s) -> Util.strEquals(m.getDestination(), s), null),
-    ARG0123(null, (m, s) -> MatchRuleMatcher.matchArg0123(m, s)),
-    ARG0123PATH(null, (m, s) -> MatchRuleMatcher.matchArg0123Path(m, s)),
-    ARG0NAMESPACE((m, s) -> MatchRuleMatcher.matchArg0Namespace(m, s), null);
+    DESTINATION((m, s) -> Objects.equals(m.getDestination(), s), null),
+    ARG0123(null, MatchRuleMatcher::matchArg0123),
+    ARG0123PATH(null, MatchRuleMatcher::matchArg0123Path),
+    ARG0NAMESPACE(MatchRuleMatcher::matchArg0Namespace, null);
 
     private final BiPredicate<Message, String> singleMatcher;
     private final BiPredicate<Message, Map<Integer, String>> multiMatcher;

dbus-java-core/src/main/java/org/freedesktop/dbus/matchrules/MatchRuleMatcher.java

@@ -6,12 +6,12 @@
 import org.freedesktop.dbus.exceptions.DBusExecutionException;
 import org.freedesktop.dbus.messages.Message;
 import org.freedesktop.dbus.utils.DBusObjects;
-import org.freedesktop.dbus.utils.Util;
 
 import java.lang.reflect.Type;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 final class MatchRuleMatcher {
 
@@ -159,7 +159,7 @@ static boolean matchPathNamespace(String _input, String _compare) {
         }
 
         for (int i = 0; i < compareSplit.length; i++) {
-            if (!Util.strEquals(compareSplit[i], inputSplit[i])) {
+            if (!Objects.equals(compareSplit[i], inputSplit[i])) {
                 return false;
             }
         }

dbus-java-core/src/main/java/org/freedesktop/dbus/utils/DBusObjects.java

@@ -41,7 +41,7 @@ private DBusObjects() {
      */
     private static <T, X extends DBusException> T requireBase(T _input, Predicate<T> _validation, Function<String, X> _exSupplier, String _customMessage) throws X {
         if (_input == null) {
-            throw _exSupplier.apply(_customMessage != null ? _customMessage : null);
+            throw _exSupplier.apply(_customMessage);
         } else if (_input instanceof String str && str.isBlank()) {
             throw _exSupplier.apply(_customMessage != null ? _customMessage : "<Empty String>");
         } else if (!_validation.test(_input)) {
@@ -194,7 +194,7 @@ public static void requireDBusSignalRule(Class<?> _type, String _source) throws
      * @since 5.2.0 - 2025-05-02
      */
     public static String requireDBusInterface(String _str) throws InvalidObjectPathException {
-        if (_str == null || _str.isEmpty() || _str.startsWith(".") || !_str.contains(".")) {
+        if (_str == null || _str.startsWith(".") || !_str.contains(".")) {
             throw new InvalidObjectPathException(_str);
         }
         return _str;

dbus-java-core/src/main/java/org/freedesktop/dbus/utils/PrimitiveUtils.java

@@ -1,42 +1,32 @@
 package org.freedesktop.dbus.utils;
 
-import java.util.Collections;
 import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * Utility class containing methods dealing with object and primitive class types.
  * @since 5.1.1 - 2024-09-15
  * @author hypfvieh
  */
 public final class PrimitiveUtils {
-    private static final Map<Class<?>, Class<?>> PRIMITIVE_TO_WRAPPER = Collections.unmodifiableMap(
-        new ConcurrentHashMap<>(
-            Map.of(
-                Boolean.TYPE, Boolean.class,
-                Byte.TYPE, Byte.class,
-                Short.TYPE, Short.class,
-                Character.TYPE, Character.class,
-                Integer.TYPE, Integer.class,
-                Long.TYPE, Long.class,
-                Float.TYPE, Float.class,
-                Double.TYPE, Double.class)
-            )
-        );
+    private static final Map<Class<?>, Class<?>> PRIMITIVE_TO_WRAPPER = Map.of(
+            Boolean.TYPE, Boolean.class,
+            Byte.TYPE, Byte.class,
+            Short.TYPE, Short.class,
+            Character.TYPE, Character.class,
+            Integer.TYPE, Integer.class,
+            Long.TYPE, Long.class,
+            Float.TYPE, Float.class,
+            Double.TYPE, Double.class);
 
-        private static final Map<Class<?>, Class<?>> WRAPPER_TO_PRIMITIVE = Collections.unmodifiableMap(
-            new ConcurrentHashMap<>(
-                Map.of(
-                    Boolean.class, Boolean.TYPE,
-                    Byte.class, Byte.TYPE,
-                    Short.class, Short.TYPE,
-                    Character.class, Character.TYPE,
-                    Integer.class, Integer.TYPE,
-                    Long.class, Long.TYPE,
-                    Float.class, Float.TYPE,
-                    Double.class, Double.TYPE)
-                )
-            );
+    private static final Map<Class<?>, Class<?>> WRAPPER_TO_PRIMITIVE = Map.of(
+            Boolean.class, Boolean.TYPE,
+            Byte.class, Byte.TYPE,
+            Short.class, Short.TYPE,
+            Character.class, Character.TYPE,
+            Integer.class, Integer.TYPE,
+            Long.class, Long.TYPE,
+            Float.class, Float.TYPE,
+            Double.class, Double.TYPE);
 
     private PrimitiveUtils() {
 
@@ -47,15 +37,15 @@ private PrimitiveUtils() {
      * @return unmodifiable map
      */
     public static Map<Class<?>, Class<?>> getPrimitiveToWrapperTypes() {
-        return Collections.unmodifiableMap(PRIMITIVE_TO_WRAPPER);
+        return PRIMITIVE_TO_WRAPPER;
     }
 
     /**
      * Map with all wrapper types and the corresponding primitive.
      * @return unmodifiable map
      */
     public static Map<Class<?>, Class<?>> getWrapperToPrimitiveTypes() {
-        return Collections.unmodifiableMap(WRAPPER_TO_PRIMITIVE);
+        return WRAPPER_TO_PRIMITIVE;
     }
 
     /**