Feat(SystemClock): Added PreciseClock implementation to the system cl…

…ock class, for the benefit of Java 8 users.

log4j-core/src/main/java/org/apache/logging/log4j/core/util/SystemClock.java

@@ -16,10 +16,15 @@
  */
 package org.apache.logging.log4j.core.util;
 
+import java.time.Instant;
+import org.apache.logging.log4j.core.time.MutableInstant;
+import org.apache.logging.log4j.core.time.PreciseClock;
+
 /**
  * Implementation of the {@code Clock} interface that returns the system time.
+ * @since 2.25
  */
-public final class SystemClock implements Clock {
+public final class SystemClock implements Clock, PreciseClock {
 
     /**
      * Returns the system time.
@@ -29,4 +34,13 @@ public final class SystemClock implements Clock {
     public long currentTimeMillis() {
         return System.currentTimeMillis();
     }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void init(final MutableInstant mutableInstant) {
+        final Instant instant = java.time.Clock.systemUTC().instant();
+        mutableInstant.initFromEpochSecond(instant.getEpochSecond(), instant.getNano());
+    }
 }

log4j-core/src/main/java/org/apache/logging/log4j/core/util/package-info.java

@@ -18,7 +18,7 @@
  * Log4j 2 helper classes.
  */
 @Export
-@Version("2.24.2")
+@Version("2.25.0")
 package org.apache.logging.log4j.core.util;
 
 import org.osgi.annotation.bundle.Export;