FileService中的变量锁是什么意思？

Question

What does the variable boolean lock mean in FileService.html#openReadChannel ?

When I tried it with false I got an illegal state exception and when with true I din't get any. I was trying to upload a file.

What does this argument do ? I have read the doc but haven't understood it.

Answer 1

According to that page, it says

lock - should the file be locked for exclusive access?

So it basically asks if you should be the only one who can access it.

If you use false then you'll probably try to write to it when someone else has access. I would assume that in almost all cases, you'll want true , since generally only one process writes to a file at a time.