Variable used in lambda expression should be final or effectively final

A final variable means that it can be instantiated only one time. in Java you can’t reassign non-final local variables in lambda as well as in anonymous inner classes.

You can refactor your code with the old for-each loop:

private TimeZone extractCalendarTimeZoneComponent(Calendar cal,TimeZone calTz) {
    try {
        for(Component component : cal.getComponents().getComponents("VTIMEZONE")) {
        VTimeZone v = (VTimeZone) component;
           if(calTz==null) {
               calTz = TimeZone.getTimeZone(v.getTimeZoneId().getValue());
    } catch (Exception e) {
        log.warn("Unable to determine ical timezone", e);
    return null;

Even if I don’t get the sense of some pieces of this code:

  • you call a v.getTimeZoneId(); without using its return value
  • with the assignment calTz = TimeZone.getTimeZone(v.getTimeZoneId().getValue()); you don’t modify the originally passed calTz and you don’t use it in this method
  • You always return null, why don’t you set void as return type?

Hope also these tips helps you to improve.

Leave a Comment