src/java.base/share/classes/java/time/Duration.java

@@ -86,12 +86,10 @@
 import java.time.temporal.ChronoUnit;
 import java.time.temporal.Temporal;
 import java.time.temporal.TemporalAmount;
 import java.time.temporal.TemporalUnit;
 import java.time.temporal.UnsupportedTemporalTypeException;
-import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 

@@ -576,12 +574,11 @@
      * Private class to delay initialization of this list until needed.
      * The circular dependency between Duration and ChronoUnit prevents
      * the simple initialization in Duration.
      */
     private static class DurationUnits {
-        static final List<TemporalUnit> UNITS =
-                Collections.unmodifiableList(Arrays.<TemporalUnit>asList(SECONDS, NANOS));
+        static final List<TemporalUnit> UNITS = List.of(SECONDS, NANOS);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Checks if this duration is zero length.