src/java.base/share/classes/java/time/chrono/ChronoPeriodImpl.java

@@ -75,12 +75,10 @@
 import java.time.temporal.TemporalAmount;
 import java.time.temporal.TemporalQueries;
 import java.time.temporal.TemporalUnit;
 import java.time.temporal.UnsupportedTemporalTypeException;
 import java.time.temporal.ValueRange;
-import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 
 /**
  * A period expressed in terms of a standard year-month-day calendar system.

@@ -103,12 +101,11 @@
     private static final long serialVersionUID = 57387258289L;
 
     /**
      * The set of supported units.
      */
-    private static final List<TemporalUnit> SUPPORTED_UNITS =
-            Collections.unmodifiableList(Arrays.<TemporalUnit>asList(YEARS, MONTHS, DAYS));
+    private static final List<TemporalUnit> SUPPORTED_UNITS = List.of(YEARS, MONTHS, DAYS);
 
     /**
      * The chronology.
      */
     private final Chronology chrono;