chinabugotech/hutool · error · NullPointerException

Date to compare is null !

Error message

Date to compare is null !

What it means

Thrown by DateTime.isBefore(Date) when the date argument is null. Unlike java.util.Date's natural behavior (which would NPE later), Hutool checks explicitly and throws NullPointerException with a descriptive message. The method delegates to compareTo(date), so a null argument is caught at the guard.

Source

Thrown at hutool-core/src/main/java/cn/hutool/core/date/DateTime.java:801

	 */
	public boolean isIn(Date beginDate, Date endDate) {
		long beginMills = beginDate.getTime();
		long endMills = endDate.getTime();
		long thisMills = this.getTime();

		return thisMills >= Math.min(beginMills, endMills) && thisMills <= Math.max(beginMills, endMills);
	}

	/**
	 * 是否在给定日期之前
	 *
	 * @param date 日期
	 * @return 是否在给定日期之前
	 * @since 4.1.3
	 */
	public boolean isBefore(Date date) {
		if (null == date) {
			throw new NullPointerException("Date to compare is null !");
		}
		return compareTo(date) < 0;
	}

	/**
	 * 是否在给定日期之前或与给定日期相等
	 *
	 * @param date 日期
	 * @return 是否在给定日期之前或与给定日期相等
	 * @since 3.0.9
	 */
	public boolean isBeforeOrEquals(Date date) {
		if (null == date) {
			throw new NullPointerException("Date to compare is null !");
		}
		return compareTo(date) <= 0;
	}

View on GitHub (pinned to 8870454b2a)

Solutions

1. Null-check the argument: if (date != null) dateTime.isBefore(date).
2. Use Objects.requireNonNullElse(date, fallback) to provide a default.
3. Wrap in a null-safe comparison utility that returns false or Optional when the argument is null.
4. Validate upstream: ensure date sources never produce null.

Example fix

// before
boolean before = dateTime.isBefore(otherDate); // throws if null

// after
boolean before = otherDate != null && dateTime.isBefore(otherDate);

if (date == null) {
    return false; // or handle per business rule
}
dateTime.isBefore(date);

static boolean isNotNull(Date date) {
    return date != null;
}

When it happens

Trigger: Calling dateTime.isBefore(null). Passing a Date variable from a nullable source (optional DB column, absent JSON field) without null-checking.

Common situations: Comparing against dates from optional fields that may be null. Processing collections of dates where some elements are null. Chaining calls where a prior parse or lookup returned null.

Related errors

• The date must not be null
• Date and Patterns must not be null
• ERA is not support offset!
• This is not a mutable object !
• Parse [{}] with format [{}] error!

AI-assisted analysis of chinabugotech/hutool@8870454b2a (2026-08-14). Data as JSON: /api/errors/f8baf23bf2707e0f. Report an issue: GitHub.