title="yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"
                                                 data-validation="custom"
                                                 data-validation-regexp="(^$|^[1-9]\d{3}\-\d\d\-\d\dT\d\d\:\d\d\:\d\d\.\d{3}Z$)"
                                                 data-validation-help="yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"/>
                                    </div>

                                                            pattern="yyyy-MM-dd'T'HH:mm:ss"/></td>
                                                    <td><c:if test="${data.endTime!=null}">
                                                        <fmt:formatDate value="${fe:date(data.endTime)}"
                                                                        pattern="yyyy-MM-dd'T'HH:mm:ss"/>

abstract class BuildReceipt : DefaultTask() {
    companion object {
        private
        val timestampFormat = newSimpleDateFormatUTC("yyyyMMddHHmmssZ")

        private
        val isoTimestampFormat = newSimpleDateFormatUTC("yyyy-MM-dd HH:mm:ss z")

        private
        fun newSimpleDateFormatUTC(pattern: String) = SimpleDateFormat(pattern).apply {
            timeZone = TimeZone.getTimeZone("UTC")
        }

Integer nullValue = IntegerConversionUtil.toInteger(null);     // Returns null
Boolean flag = BooleanConversionUtil.toBoolean("true");        // Returns true
Date date = DateConversionUtil.toDate("2023-12-25", "yyyy-MM-dd");

// Primitive conversions with default values
int primitiveInt = IntegerConversionUtil.toPrimitiveInt(value, "0");  // Default to 0 if null
```

### Collection Utilities with Java 21 Support
```java

				</div>
				<div class="info">
					<fmt:formatDate value="${fe:parseDate(doc.last_modified)}" type="BOTH" pattern="yyyy-MM-dd HH:mm" />
					<c:if test="${doc.last_modified==null || doc.last_modified==''}">
						<fmt:formatDate value="${fe:parseDate(doc.created)}" type="BOTH" pattern="yyyy-MM-dd HH:mm" />
					</c:if>
					<c:if test="${doc.content_length!=null && doc.content_length!=''}">
						<div class="d-sm-none"></div>

                                        <td><fmt:formatDate value="${fe:date(updatedTime)}"
                                                            pattern="yyyy-MM-dd'T'HH:mm:ss"/></td>
                                    </tr>
                                    </tbody>
                                </table>
                            </div>

                                                    <td><fmt:formatDate
                                                            value="${fe:date(data.createdTime)}"
                                                            pattern="yyyy-MM-dd'T'HH:mm:ss"/></td>
                                                </tr>
                                            </c:forEach>
                                            </tbody>

    protected boolean isValidDateFormat(final String date) {
        if (date == null || date.isEmpty()) {
            return true; // Date is optional
        }
        // Basic validation for W3C Datetime format (YYYY-MM-DD or YYYY-MM-DDThh:mm:ss+00:00)
        // This is a simplified validation
        if (date.length() < 10) {
            if (logger.isDebugEnabled()) {
                logger.debug("Invalid date format (too short): {}", date);

                                                                value="${fe:date(data.lastAccessTime)}"
                                                                pattern="yyyy-MM-dd'T'HH:mm:ss"/></td>
                                                    </tr>
                                                </c:forEach>
                                                </tbody>

     */
    private String loc;

    /**
     * The date of last modification of the file. This date should be in W3C
     * Datetime format. This format allows you to omit the time portion, if
     * desired, and use YYYY-MM-DD.
     *
     * Note that this tag is separate from the If-Modified-Since (304) header
     * the server can return, and search engines may use the information from
     * both sources differently.
     */