src/java.base/share/classes/java/time/format/DateTimeFormatter.java

@@ -921,10 +921,11 @@
      * The format consists of:
      * <ul>
      * <li>The {@link #ISO_LOCAL_DATE_TIME}
      * <li>The {@link ZoneOffset#getId() offset ID}. If the offset has seconds then
      *  they will be handled even though this is not part of the ISO-8601 standard.
+     *  The offset parsing is lenient, which allows the minutes and seconds to be optional.
      *  Parsing is case insensitive.
      * </ul>
      * <p>
      * The returned formatter has a chronology of ISO set to ensure dates in
      * other calendar systems are correctly converted.

@@ -933,11 +934,13 @@
     public static final DateTimeFormatter ISO_OFFSET_DATE_TIME;
     static {
         ISO_OFFSET_DATE_TIME = new DateTimeFormatterBuilder()
                 .parseCaseInsensitive()
                 .append(ISO_LOCAL_DATE_TIME)
+                .parseLenient()
                 .appendOffsetId()
+                .parseStrict()
                 .toFormatter(ResolverStyle.STRICT, IsoChronology.INSTANCE);
     }
 
     //-----------------------------------------------------------------------
     /**

@@ -1158,10 +1161,11 @@
      * <li>Two digits for the {@link ChronoField#DAY_OF_MONTH day-of-month}.
      *  This is pre-padded by zero to ensure two digits.
      * <li>If the offset is not available to format or parse then the format is complete.
      * <li>The {@link ZoneOffset#getId() offset ID} without colons. If the offset has
      *  seconds then they will be handled even though this is not part of the ISO-8601 standard.
+     *  The offset parsing is lenient, which allows the minutes and seconds to be optional.
      *  Parsing is case insensitive.
      * </ul>
      * <p>
      * As this formatter has an optional element, it may be necessary to parse using
      * {@link DateTimeFormatter#parseBest}.

@@ -1176,11 +1180,13 @@
                 .parseCaseInsensitive()
                 .appendValue(YEAR, 4)
                 .appendValue(MONTH_OF_YEAR, 2)
                 .appendValue(DAY_OF_MONTH, 2)
                 .optionalStart()
+                .parseLenient()
                 .appendOffset("+HHMMss", "Z")
+                .parseStrict()
                 .toFormatter(ResolverStyle.STRICT, IsoChronology.INSTANCE);
     }
 
     //-----------------------------------------------------------------------
     /**