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

…lock class, for the benefit of Java 8 users. (#3217)

Added PreciseClock implementation to the system clock class, for the benefit of Java 8 users.

Co-authored-by: Jay Katariya <[email protected]>
Co-authored-by: Piotr P. Karwasz <[email protected]>

log4j-core-java9/src/assembly/java9.xml

@@ -31,7 +31,6 @@
         <include>org/apache/logging/log4j/core/jackson/Log4jStackTraceElementDeserializer.class</include>
         <include>org/apache/logging/log4j/core/jackson/StackTraceElementMixIn.class</include>
         <include>org/apache/logging/log4j/core/util/internal/UnsafeUtil*.class</include>
-        <include>org/apache/logging/log4j/core/util/SystemClock.class</include>
       </includes>
     </fileSet>
   </fileSets>

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

@@ -16,10 +16,14 @@
  */
 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.
  */
-public final class SystemClock implements Clock {
+public final class SystemClock implements Clock, PreciseClock {
 
     /**
      * Returns the system time.
@@ -29,4 +33,10 @@ public final class SystemClock implements Clock {
     public long currentTimeMillis() {
         return System.currentTimeMillis();
     }
+
+    @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;