Remove deprecations from functional interfaces

Author: ppkarwasz

log4j-api-test/src/test/java/org/apache/logging/log4j/internal/map/UnmodifiableArrayBackedMapTest.java

@@ -24,13 +24,15 @@
 import static org.junit.jupiter.api.Assertions.fail;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.Map;
 import java.util.Set;
+import org.apache.logging.log4j.util.ReadOnlyStringMap;
 import org.apache.logging.log4j.util.TriConsumer;
 import org.junit.jupiter.api.Test;
 
@@ -238,32 +240,18 @@ public void testEqualsWhenOneValueDiffers() {
 
     @Test
     public void testForEachBiConsumer_JavaUtil() {
-        UnmodifiableArrayBackedMap map = UnmodifiableArrayBackedMap.EMPTY_MAP.copyAndPutAll(getTestParameters());
-        Set<String> keys = new HashSet<>();
-        java.util.function.BiConsumer<String, String> java_util_action =
-                new java.util.function.BiConsumer<String, String>() {
-                    @Override
-                    public void accept(String key, String value) {
-                        keys.add(key);
-                    }
-                };
-        map.forEach(java_util_action);
+        final Map<String, String> map = UnmodifiableArrayBackedMap.EMPTY_MAP.copyAndPutAll(getTestParameters());
+        final Collection<String> keys = new HashSet<>();
+        map.forEach((key, value) -> keys.add(key));
         assertEquals(map.keySet(), keys);
     }
 
     @Test
     public void testForEachBiConsumer_Log4jUtil() {
-        UnmodifiableArrayBackedMap map = UnmodifiableArrayBackedMap.EMPTY_MAP.copyAndPutAll(getTestParameters());
-        Set<String> keys = new HashSet<>();
-        org.apache.logging.log4j.util.BiConsumer<String, String> log4j_util_action =
-                new org.apache.logging.log4j.util.BiConsumer<String, String>() {
-                    @Override
-                    public void accept(String key, String value) {
-                        keys.add(key);
-                    }
-                };
-        map.forEach(log4j_util_action);
-        assertEquals(map.keySet(), keys);
+        final ReadOnlyStringMap map = UnmodifiableArrayBackedMap.EMPTY_MAP.copyAndPutAll(getTestParameters());
+        final Collection<String> keys = new HashSet<>();
+        map.forEach((key, value) -> keys.add(key));
+        assertEquals(map.toMap().keySet(), keys);
     }
 
     @Test

log4j-api/src/main/java/org/apache/logging/log4j/LogBuilder.java

@@ -32,7 +32,7 @@ public interface LogBuilder {
      * @param marker The Marker to log.
      * @return The LogBuilder.
      */
-    default LogBuilder withMarker(Marker marker) {
+    default LogBuilder withMarker(final Marker marker) {
         return this;
     }
 
@@ -41,7 +41,7 @@ default LogBuilder withMarker(Marker marker) {
      * @param throwable The Throwable to log.
      * @return the LogBuilder.
      */
-    default LogBuilder withThrowable(Throwable throwable) {
+    default LogBuilder withThrowable(final Throwable throwable) {
         return this;
     }
 
@@ -59,21 +59,21 @@ default LogBuilder withLocation() {
      * @param location The stack trace element to include in the log event.
      * @return The LogBuilder.
      */
-    default LogBuilder withLocation(StackTraceElement location) {
+    default LogBuilder withLocation(final StackTraceElement location) {
         return this;
     }
 
     /**
      * Causes all the data collected to be logged along with the message. Interface default method does nothing.
      * @param message The message to log.
      */
-    default void log(CharSequence message) {}
+    default void log(final CharSequence message) {}
 
     /**
      * Causes all the data collected to be logged along with the message. Interface default method does nothing.
      * @param message The message to log.
      */
-    default void log(String message) {}
+    default void log(final String message) {}
 
     /**
      * Logs a message with parameters. Interface default method does nothing.
@@ -83,29 +83,27 @@ default void log(String message) {}
      *
      * @see org.apache.logging.log4j.util.Unbox
      */
-    default void log(String message, Object... params) {}
+    default void log(final String message, final Object... params) {}
 
     /**
      * Causes all the data collected to be logged along with the message and parameters.
      * Interface default method does nothing.
      * @param message The message.
      * @param params Parameters to the message.
      */
-    @SuppressWarnings("deprecation")
-    default void log(String message, Supplier<?>... params) {}
+    default void log(final String message, final Supplier<?>... params) {}
 
     /**
      * Causes all the data collected to be logged along with the message. Interface default method does nothing.
      * @param message The message to log.
      */
-    default void log(Message message) {}
+    default void log(final Message message) {}
 
     /**
      * Causes all the data collected to be logged along with the message. Interface default method does nothing.
      * @param messageSupplier The supplier of the message to log.
      */
-    @SuppressWarnings("deprecation")
-    default void log(Supplier<Message> messageSupplier) {}
+    default void log(final Supplier<Message> messageSupplier) {}
 
     /**
      * Causes all the data collected to be logged along with the message.
@@ -114,7 +112,6 @@ default void log(Supplier<Message> messageSupplier) {}
      * @return the message logger or {@code null} if no logging occurred.
      * @since 2.20
      */
-    @SuppressWarnings("deprecation")
     default Message logAndGet(final Supplier<Message> messageSupplier) {
         return null;
     }
@@ -123,7 +120,7 @@ default Message logAndGet(final Supplier<Message> messageSupplier) {
      * Causes all the data collected to be logged along with the message. Interface default method does nothing.
      * @param message The message to log.
      */
-    default void log(Object message) {}
+    default void log(final Object message) {}
 
     /**
      * Logs a message with parameters. Interface default method does nothing.
@@ -133,7 +130,7 @@ default void log(Object message) {}
      *
      * @see org.apache.logging.log4j.util.Unbox
      */
-    default void log(String message, Object p0) {}
+    default void log(final String message, final Object p0) {}
 
     /**
      * Logs a message with parameters. Interface default method does nothing.
@@ -144,7 +141,7 @@ default void log(String message, Object p0) {}
      *
      * @see org.apache.logging.log4j.util.Unbox
      */
-    default void log(String message, Object p0, Object p1) {}
+    default void log(final String message, final Object p0, final Object p1) {}
 
     /**
      * Logs a message with parameters. Interface default method does nothing.
@@ -156,7 +153,7 @@ default void log(String message, Object p0, Object p1) {}
      *
      * @see org.apache.logging.log4j.util.Unbox
      */
-    default void log(String message, Object p0, Object p1, Object p2) {}
+    default void log(final String message, final Object p0, final Object p1, final Object p2) {}
 
     /**
      * Logs a message with parameters. Interface default method does nothing.
@@ -169,7 +166,7 @@ default void log(String message, Object p0, Object p1, Object p2) {}
      *
      * @see org.apache.logging.log4j.util.Unbox
      */
-    default void log(String message, Object p0, Object p1, Object p2, Object p3) {}
+    default void log(final String message, final Object p0, final Object p1, final Object p2, final Object p3) {}
 
     /**
      * Logs a message with parameters. Interface default method does nothing.
@@ -183,7 +180,13 @@ default void log(String message, Object p0, Object p1, Object p2, Object p3) {}
      *
      * @see org.apache.logging.log4j.util.Unbox
      */
-    default void log(String message, Object p0, Object p1, Object p2, Object p3, Object p4) {}
+    default void log(
+            final String message,
+            final Object p0,
+            final Object p1,
+            final Object p2,
+            final Object p3,
+            final Object p4) {}
 
     /**
      * Logs a message with parameters. Interface default method does nothing.
@@ -198,7 +201,14 @@ default void log(String message, Object p0, Object p1, Object p2, Object p3, Obj
      *
      * @see org.apache.logging.log4j.util.Unbox
      */
-    default void log(String message, Object p0, Object p1, Object p2, Object p3, Object p4, Object p5) {}
+    default void log(
+            final String message,
+            final Object p0,
+            final Object p1,
+            final Object p2,
+            final Object p3,
+            final Object p4,
+            final Object p5) {}
 
     /**
      * Logs a message with parameters.
@@ -214,7 +224,15 @@ default void log(String message, Object p0, Object p1, Object p2, Object p3, Obj
      *
      * @see org.apache.logging.log4j.util.Unbox
      */
-    default void log(String message, Object p0, Object p1, Object p2, Object p3, Object p4, Object p5, Object p6) {}
+    default void log(
+            final String message,
+            final Object p0,
+            final Object p1,
+            final Object p2,
+            final Object p3,
+            final Object p4,
+            final Object p5,
+            final Object p6) {}
 
     /**
      * Logs a message with parameters. Interface default method does nothing.
@@ -232,7 +250,15 @@ default void log(String message, Object p0, Object p1, Object p2, Object p3, Obj
      * @see org.apache.logging.log4j.util.Unbox
      */
     default void log(
-            String message, Object p0, Object p1, Object p2, Object p3, Object p4, Object p5, Object p6, Object p7) {}
+            final String message,
+            final Object p0,
+            final Object p1,
+            final Object p2,
+            final Object p3,
+            final Object p4,
+            final Object p5,
+            final Object p6,
+            final Object p7) {}
 
     /**
      * Logs a message with parameters. Interface default method does nothing.
@@ -251,16 +277,16 @@ default void log(
      * @see org.apache.logging.log4j.util.Unbox
      */
     default void log(
-            String message,
-            Object p0,
-            Object p1,
-            Object p2,
-            Object p3,
-            Object p4,
-            Object p5,
-            Object p6,
-            Object p7,
-            Object p8) {}
+            final String message,
+            final Object p0,
+            final Object p1,
+            final Object p2,
+            final Object p3,
+            final Object p4,
+            final Object p5,
+            final Object p6,
+            final Object p7,
+            final Object p8) {}
 
     /**
      * Logs a message with parameters. Interface default method does nothing.
@@ -280,17 +306,17 @@ default void log(
      * @see org.apache.logging.log4j.util.Unbox
      */
     default void log(
-            String message,
-            Object p0,
-            Object p1,
-            Object p2,
-            Object p3,
-            Object p4,
-            Object p5,
-            Object p6,
-            Object p7,
-            Object p8,
-            Object p9) {}
+            final String message,
+            final Object p0,
+            final Object p1,
+            final Object p2,
+            final Object p3,
+            final Object p4,
+            final Object p5,
+            final Object p6,
+            final Object p7,
+            final Object p8,
+            final Object p9) {}
 
     /**
      * Causes all the data collected to be logged. Default implementatoin does nothing.

log4j-api/src/main/java/org/apache/logging/log4j/LogManager.java

@@ -41,15 +41,15 @@
 public class LogManager {
 
     /**
-     * Log4j property to set to the fully qualified class name of a custom implementation of
+     * Log4j's property to set to the fully qualified class name of a custom implementation of
      * {@link LoggerContextFactory}.
      * @deprecated Replaced since 2.24.0 with {@value org.apache.logging.log4j.spi.Provider#PROVIDER_PROPERTY_NAME}.
      */
     @Deprecated
     public static final String FACTORY_PROPERTY_NAME = "log4j2.loggerContextFactory";
 
     /**
-     * The name of the root Logger is {@value #ROOT_LOGGER_NAME}.
+     * The name of the root Logger.
      */
     public static final String ROOT_LOGGER_NAME = Strings.EMPTY;
 
@@ -315,10 +315,10 @@ protected static LoggerContext getContext(
     /**
      * Shutdown using the LoggerContext appropriate for the caller of this method.
      * This is equivalent to calling {@code LogManager.shutdown(false)}.
-     *
-     * This call is synchronous and will block until shut down is complete.
-     * This may include flushing pending log events over network connections.
-     *
+     * <p>
+     *     This call is synchronous and will block until shut down is complete. This may include flushing pending log
+     *     events over network connections.
+     * </p>
      * @since 2.6
      */
     public static void shutdown() {
@@ -328,9 +328,10 @@ public static void shutdown() {
     /**
      * Shutdown the logging system if the logging system supports it.
      * This is equivalent to calling {@code LogManager.shutdown(LogManager.getContext(currentContext))}.
-     *
-     * This call is synchronous and will block until shut down is complete.
-     * This may include flushing pending log events over network connections.
+     * <p>
+     *     This call is synchronous and will block until shut down is complete. This may include flushing pending log
+     *     events over network connections.
+     * </p>
      *
      * @param currentContext if true a default LoggerContext (may not be the LoggerContext used to create a Logger
      *            for the calling class) will be used.
@@ -347,9 +348,10 @@ public static void shutdown(final boolean currentContext) {
     /**
      * Shutdown the logging system if the logging system supports it.
      * This is equivalent to calling {@code LogManager.shutdown(LogManager.getContext(currentContext))}.
-     *
-     * This call is synchronous and will block until shut down is complete.
-     * This may include flushing pending log events over network connections.
+     * <p>
+     *     This call is synchronous and will block until shut down is complete. This may include flushing pending log
+     *     events over network connections.
+     * </p>
      *
      * @param currentContext if true a default LoggerContext (may not be the LoggerContext used to create a Logger
      *            for the calling class) will be used.
@@ -366,9 +368,10 @@ public static void shutdown(final boolean currentContext, final boolean allConte
 
     /**
      * Shutdown the logging system if the logging system supports it.
-     *
-     * This call is synchronous and will block until shut down is complete.
-     * This may include flushing pending log events over network connections.
+     * <p>
+     *     This call is synchronous and will block until shut down is complete. This may include flushing pending log
+     *     events over network connections.
+     * </p>
      *
      * @param context the LoggerContext.
      * @since 2.6
@@ -461,7 +464,7 @@ public static Logger getFormatterLogger(final Class<?> clazz) {
      * Short-hand for {@code getLogger(value, StringFormatterMessageFactory.INSTANCE)}
      * </p>
      *
-     * @param value The value's whose class name should be used as the Logger name.
+     * @param value The value whose class name should be used as the Logger name.
      * @return The Logger, created with a {@link StringFormatterMessageFactory}
      * @throws UnsupportedOperationException if {@code value} is {@code null} and the calling class cannot be
      *             determined.

log4j-api/src/main/java/org/apache/logging/log4j/Logger.java

@@ -200,7 +200,6 @@ public interface Logger {
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void debug(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -222,7 +221,6 @@ public interface Logger {
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void debug(Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -235,7 +233,6 @@ public interface Logger {
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void debug(Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -329,7 +326,6 @@ public interface Logger {
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void debug(String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -348,7 +344,6 @@ public interface Logger {
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void debug(Supplier<?> messageSupplier);
 
     /**
@@ -360,7 +355,6 @@ public interface Logger {
      * @param throwable the {@code Throwable} to log, including its stack trace.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void debug(Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -811,7 +805,6 @@ void debug(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void error(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -833,7 +826,6 @@ void debug(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void error(Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -846,7 +838,6 @@ void debug(
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void error(Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -940,7 +931,6 @@ void debug(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void error(String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -959,7 +949,6 @@ void debug(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void error(Supplier<?> messageSupplier);
 
     /**
@@ -971,7 +960,6 @@ void debug(
      * @param throwable the {@code Throwable} to log, including its stack trace.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void error(Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -1414,7 +1402,6 @@ void error(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void fatal(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -1436,7 +1423,6 @@ void error(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void fatal(Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -1449,7 +1435,6 @@ void error(
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void fatal(Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -1543,7 +1528,6 @@ void error(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void fatal(String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -1562,7 +1546,6 @@ void error(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void fatal(Supplier<?> messageSupplier);
 
     /**
@@ -1574,7 +1557,6 @@ void error(
      * @param throwable the {@code Throwable} to log, including its stack trace.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void fatal(Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -1901,12 +1883,13 @@ void fatal(
 
     /**
      * Gets the message factory used to convert message Objects and Strings/CharSequences into actual log Messages.
-     *
-     * Since version 2.6, Log4j internally uses message factories that implement the {@link MessageFactory2} interface.
-     * From version 2.6.2, the return type of this method was changed from {@link MessageFactory} to
-     * {@code <MF extends MessageFactory> MF}. The returned factory will always implement {@link MessageFactory2},
-     * but the return type of this method could not be changed to {@link MessageFactory2} without breaking binary
-     * compatibility.
+     * <p>
+     *     Since version 2.6, Log4j internally uses message factories that implement the {@link MessageFactory2}
+     *     interface. From version 2.6.2, the return type of this method was changed from {@link MessageFactory} to
+     *     {@code <MF extends MessageFactory> MF}. The returned factory will always implement {@link MessageFactory2},
+     *     but the return type of this method could not be changed to {@link MessageFactory2} without breaking binary
+     *     compatibility.
+     * </p>
      *
      * @return the message factory, as an instance of {@link MessageFactory2}
      */
@@ -2030,7 +2013,6 @@ void fatal(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void info(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -2052,7 +2034,6 @@ void fatal(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void info(Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -2065,7 +2046,6 @@ void fatal(
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void info(Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -2159,7 +2139,6 @@ void fatal(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void info(String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -2178,7 +2157,6 @@ void fatal(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void info(Supplier<?> messageSupplier);
 
     /**
@@ -2190,7 +2168,6 @@ void fatal(
      * @param throwable the {@code Throwable} to log, including its stack trace.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void info(Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -2737,7 +2714,6 @@ void info(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void log(Level level, Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -2760,7 +2736,6 @@ void info(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void log(Level level, Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -2774,7 +2749,6 @@ void info(
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void log(Level level, Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -2878,7 +2852,6 @@ void info(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void log(Level level, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -2899,7 +2872,6 @@ void info(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void log(Level level, Supplier<?> messageSupplier);
 
     /**
@@ -2912,7 +2884,6 @@ void info(
      * @param throwable the {@code Throwable} to log, including its stack log.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void log(Level level, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -3435,7 +3406,6 @@ void log(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void trace(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -3458,7 +3428,6 @@ void log(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void trace(Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -3471,7 +3440,6 @@ void log(
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void trace(Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -3567,7 +3535,6 @@ void log(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void trace(String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -3587,7 +3554,6 @@ void log(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void trace(Supplier<?> messageSupplier);
 
     /**
@@ -3599,7 +3565,6 @@ void log(
      * @param throwable the {@code Throwable} to log, including its stack trace.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void trace(Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -3967,7 +3932,6 @@ void trace(
      *
      * @since 2.6
      */
-    @SuppressWarnings("deprecation")
     EntryMessage traceEntry(Supplier<?>... paramSuppliers);
 
     /**
@@ -3986,7 +3950,6 @@ void trace(
      *
      * @since 2.6
      */
-    @SuppressWarnings("deprecation")
     EntryMessage traceEntry(String format, Supplier<?>... paramSuppliers);
 
     /**
@@ -4205,7 +4168,6 @@ void trace(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void warn(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -4227,7 +4189,6 @@ void trace(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void warn(Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -4240,7 +4201,6 @@ void trace(
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void warn(Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -4334,7 +4294,6 @@ void trace(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void warn(String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -4353,7 +4312,6 @@ void trace(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void warn(Supplier<?> messageSupplier);
 
     /**
@@ -4365,7 +4323,6 @@ void trace(
      * @param throwable the {@code Throwable} to log, including its stack warn.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
     void warn(Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -4695,7 +4652,12 @@ void warn(
      * @since 2.13.0
      */
     default void logMessage(
-            Level level, Marker marker, String fqcn, StackTraceElement location, Message message, Throwable throwable) {
+            final Level level,
+            final Marker marker,
+            final String fqcn,
+            final StackTraceElement location,
+            final Message message,
+            final Throwable throwable) {
         // noop
     }
 
@@ -4768,7 +4730,7 @@ default LogBuilder always() {
      * @return a LogBuilder.
      * @since 2.13.0
      */
-    default LogBuilder atLevel(Level level) {
+    default LogBuilder atLevel(final Level level) {
         return LogBuilder.NOOP;
     }
 }

log4j-api/src/main/java/org/apache/logging/log4j/util/BiConsumer.java

@@ -24,12 +24,14 @@
  * @see ReadOnlyStringMap
  * @since 2.7
  */
-public interface BiConsumer<K, V> {
+@FunctionalInterface
+public interface BiConsumer<K, V> extends java.util.function.BiConsumer<K, V> {
 
     /**
      * Performs the operation given the specified arguments.
      * @param k the first input argument
      * @param v the second input argument
      */
+    @Override
     void accept(K k, V v);
 }

log4j-api/src/main/java/org/apache/logging/log4j/util/LambdaUtil.java

@@ -35,7 +35,6 @@ private LambdaUtil() {}
      * @return an array containing the results of evaluating the lambda expressions (or {@code null} if the suppliers
      *         array was {@code null}
      */
-    @SuppressWarnings("deprecation")
     public static Object[] getAll(final Supplier<?>... suppliers) {
         if (suppliers == null) {
             return null;
@@ -54,7 +53,6 @@ public static Object[] getAll(final Supplier<?>... suppliers) {
      * @return the results of evaluating the lambda expression (or {@code null} if the supplier
      *         was {@code null}
      */
-    @SuppressWarnings("deprecation")
     public static Object get(final Supplier<?> supplier) {
         if (supplier == null) {
             return null;
@@ -83,7 +81,6 @@ public static Message get(final MessageSupplier supplier) {
      * @return the Message resulting from evaluating the lambda expression or the Message created by the factory for
      * supplied values that are not of type Message
      */
-    @SuppressWarnings("deprecation")
     public static Message getMessage(final Supplier<?> supplier, final MessageFactory messageFactory) {
         if (supplier == null) {
             return null;

log4j-api/src/main/java/org/apache/logging/log4j/util/MessageSupplier.java

@@ -33,12 +33,14 @@
  *
  * @since 2.4
  */
-public interface MessageSupplier {
+@FunctionalInterface
+public interface MessageSupplier extends Supplier<Message> {
 
     /**
      * Gets a Message.
      *
      * @return a Message
      */
+    @Override
     Message get();
 }

log4j-api/src/main/java/org/apache/logging/log4j/util/Supplier.java

@@ -31,14 +31,15 @@
  *
  * @since 2.4
  */
+@FunctionalInterface
 @InternalApi
-@Deprecated
-public interface Supplier<T> {
+public interface Supplier<T> extends java.util.function.Supplier<T> {
 
     /**
      * Gets a value.
      *
      * @return a value
      */
+    @Override
     T get();
 }