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  1. JDK
  2. JDK-8257647

"UTC" time zone inconsistently parsed with "DateTimeFormatter" after Java11

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: P4
    • Resolution: Not an Issue
    • Affects Version/s: 11, 15, 16
    • Fix Version/s: None
    • Component/s: core-libs
    • Subcomponent:
    • CPU:
      generic
    • OS:
      generic

      Description

      ADDITIONAL SYSTEM INFORMATION :
      Windows Server 2019, macOS 10.15, Ubuntu 18.04.
      Java 11, Java 15.

      A DESCRIPTION OF THE PROBLEM :
      The `UTC` time zone specified in a String with date and time is parsed to a different `ZoneId` in Java11+ rather than in Java8.

      Consider the following pattern `MM/dd/yyyy hh:mm a z` used to create a `DateTimeFormatter` with the US locale.

      When a date string such as e.g. `05/17/2021 09:23 PM UTC` is parsed to a `ZonedDateTime` using the formatter, the `ZoneId` value of the `ZonedDateTime` is different when different JDK versions are used.

      For JDK 8-10 and 12-14 the value of the `ZoneId` is `UTC`. But for JDK 11 and JDK 15 the value is equal to `Etc/UTC`.

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      The easiest way to reproduce the issue is to clone the repository https://github.com/yuri-sergiichuk/jdk-zone-parsing-inconsistency and run Gradle build `./gradlew build`.

      1. Create `DateTimeFormatter` with the `MM/dd/yyyy hh:mm a z` pattern:

          ```
          DateTimeFormatter ZONED_FORMATTER = DateTimeFormatter.ofPattern("MM/dd/yyyy hh:mm a z", Locale.US);
          ```

      2. Parse date-time string `05/17/2021 09:23 PM UTC` to a `ZonedDateTime` object:

          ```
          ZonedDateTime result = ZONED_FORMATTER.parse(dateString, ZonedDateTime::from);
          ```

      3. Check `ZoneId` value of the result:

          ```
          result.getZone().equals(ZoneId.of("UTC"))
          ```


      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      The parsed `ZonedDateTime` zone is equal to `ZoneId.of("UTC")`.
      ACTUAL -
      The parsed `ZonedDateTime` zone is equal to `ZoneId.of("Etc/UTC")`.

      ---------- BEGIN SOURCE ----------
      final class ZonedParser {

          public static void main(String[] args) {
              DateTimeFormatter ZONED_FORMATTER = DateTimeFormatter.ofPattern("MM/dd/yyyy hh:mm a z", Locale.US);
              ZonedDateTime result = ZONED_FORMATTER.parse("05/17/2021 09:23 PM UTC", ZonedDateTime::from);
              if (!result.getZone().equals(ZoneId.of("UTC"))) {
                  throw new IllegalStateException("Zone ID must be equal to `UTC`.");
              }
          }
      }
      ---------- END SOURCE ----------

      CUSTOMER SUBMITTED WORKAROUND :
      Use `Etc/UTC` time zone in date string in Java 11 and Java 15 and just `UTC` in others.

      FREQUENCY : always


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              Assignee:
              naoto Naoto Sato
              Reporter:
              webbuggrp Webbug Group
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                Updated:
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