conditional sum in map.foreach java8

public Double getUnitsBefore(Date recordDate) {
    double eligibleUnits = 0;
    ageBucket.forEach((dateStr, units) -> {
        try {
            Date date = DFT.parse(dateStr);
            if (date.before(recordDate)) {
                //TODO These are eligible units for dividend.
                eligibleUnits = eligibleUnits + units.doubleValue();    //TODO 
            }

        } catch(ParseException e) {
            e.printStackTrace();
        }
    });

    return eligibleUnits;
}

• As you know line eligibleUnits = eligibleUnits + units.doubleValue(); does not compile in Java 8. How do i achieve this? I need to sum only when date is before record date.