Will iterator be damaged if remove() called but did nothing?

Question

Suppose I am iterating over some collection, then call remove() with absent key so that it does nothing. Will next iteration cause exception?

What happens when you try it out? – Jesper Jun 06 '12 at 11:56 — Jesper, Jun 06 '12 at 11:56

score 4 · Answer 1 · answered Jun 06 '12 at 12:01

4

First of all, the ConcurrentModificationException is optional. A compliant container does not have to attempt to spot concurrent modifications at all.

However, most standard containers tend to do it.

I've just checked a couple of them in JDK7, and they only bump up the modification count once they have found the element.

Having said that, I would discourage you from relying on this behaviour.

answered Jun 06 '12 at 12:01

NPE

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If you know you're removing an absent key, you deliberately do a no-op. If you don't know, then you deliberately court a `ConcurrentModificationException`. In both cases, you're doing something silly or wrong. – Louis Wasserman Jun 06 '12 at 14:23

Will iterator be damaged if remove() called but did nothing?

1 Answers1