[LANG-1462] Use TimeZone from calendar in DateFormatUtils.

Adapted from PR #863 by mbuiakova with:
- No SpotBugs failure
- Refactored common code
- Moved new test method to proper location in test class.

src/changes/changes.xml

@@ -69,6 +69,7 @@ The <action> type attribute can be add,update,fix,remove.
     <action                   type="fix" dev="ggregory" due-to="Gary Gregory">ArrayUtils.toPrimitive(Boolean...) null array elements map to false, like Boolean.parseBoolean(null) and its callers return false.</action>
     <action                   type="fix" dev="ggregory" due-to="CodeQL, Gary Gregory">StrBuilder.StrBuilderReader.skip(long): Throw an exception when an implicit narrowing conversion in a compound assignment would result in information loss or a numeric error such as an overflows.</action>
     <action                   type="fix" dev="ggregory" due-to="Gary Gregory">Deprecate Validate#notNull(Object) in favor of using Objects#requireNonNull(Object, String).</action>
+    <action issue="LANG-1462" type="fix" dev="ggregory" due-to="Lijun Liang, Arun Avanathan, Tai Dupree, Maria Buiakova, Gary Gregory">Use TimeZone from calendar in DateFormatUtils.</action>
     <!-- ADD -->
     <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add EnumUtils.getEnumSystemProperty(...).</action>
     <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add TriConsumer.</action>

src/main/java/org/apache/commons/lang3/time/DateFormatUtils.java

@@ -271,7 +271,8 @@ public class DateFormatUtils {
     }
 
     /**
-     * <p>Formats a calendar into a specific pattern.</p>
+     * <p>Formats a calendar into a specific pattern. The TimeZone from the calendar
+     * will be used for formatting.</p>
      *
      * @param calendar  the calendar to format, not null
      * @param pattern  the pattern to use to format the calendar, not null
@@ -280,7 +281,7 @@ public class DateFormatUtils {
      * @since 2.4
      */
     public static String format(final Calendar calendar, final String pattern) {
-        return format(calendar, pattern, null, null);
+        return format(calendar, pattern, getTimeZone(calendar), null);
     }
 
     /**
@@ -346,7 +347,8 @@ public class DateFormatUtils {
     }
 
     /**
-     * <p>Formats a calendar into a specific pattern in a locale.</p>
+     * <p>Formats a calendar into a specific pattern in a locale. The TimeZone from the calendar
+     * will be used for formatting.</p>
      *
      * @param calendar  the calendar to format, not null
      * @param pattern  the pattern to use to format the calendar, not null
@@ -356,7 +358,7 @@ public class DateFormatUtils {
      * @since 2.4
      */
     public static String format(final Calendar calendar, final String pattern, final Locale locale) {
-        return format(calendar, pattern, null, locale);
+        return format(calendar, pattern, getTimeZone(calendar), locale);
     }
 
     /**
@@ -402,4 +404,8 @@ public class DateFormatUtils {
         return df.format(calendar);
     }
 
+    private static TimeZone getTimeZone(final Calendar calendar) {
+        return calendar == null ? null : calendar.getTimeZone();
+    }
+
 }

src/test/java/org/apache/commons/lang3/time/DateFormatUtilsTest.java

@@ -150,6 +150,15 @@ public class DateFormatUtilsTest {
         DateFormatUtils.ISO_DATETIME_TIME_ZONE_FORMAT.parse(date);
     }
 
+    @Test
+    public void testLANG1462() {
+        TimeZone timeZone = TimeZone.getTimeZone("GMT-3");
+        Calendar calendar = createJuneTestDate(timeZone);
+        assertEquals("20030608101112", DateFormatUtils.format(calendar, "yyyyMMddHHmmss"));
+        calendar.setTimeZone(TimeZone.getTimeZone("JST"));
+        assertEquals("20030608221112", DateFormatUtils.format(calendar, "yyyyMMddHHmmss"));
+    }
+
     @DefaultTimeZone("UTC")
     @Test
     public void testLang530() throws ParseException {