I read that an object can be strongly, weakly or even phantom (!!!!) reachable..

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Question: I read that an object can be strongly, weakly or even phantom (!!!!) reachable... ???

Answer: I found the definitions in API. I think it is clear enough to be cited here:

Going from strongest to weakest, the different levels of reachability reflect the life cycle of an object. They are operationally defined as follows:

• An object is strongly reachable if it can be reached by some thread without traversing any reference objects. A newly-created object is strongly reachable by the thread that created it.
• An object is softly reachable if it is not strongly reachable but can be reached by traversing a soft reference.
• An object is weakly reachable if it is neither strongly nor softly reachable but can be reached by traversing a weak reference. When the weak references to a weakly-reachable object are cleared, the object becomes eligible for finalization.
• An object is phantom reachable if it is neither strongly, softly,
  nor weakly reachable, it has been finalized, and some phantom
  reference refers to it.
• Finally, an object is unreachable, and therefore eligible for
  reclamation, when it is not reachable in any of the above ways.

About phantom reference please read more in API (java.lang.ref.PhantomReference)

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30 comments |    | Score: 3.33

I use logging in my application... The problem is that I am opening the PrintWri

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Question: I use logging in my application... The problem is that I am opening the PrintWriter stream only once and keep it open until my application is stopped. Open PrintWriter stream does not let to open logs in text editor and users can not read logs...
Appears a error message like this: "Can not open file, it used by another application…"
Is it possible to solve the problem?

Answer: It depends on OS type. For example in Windows NT you can use command "type":

type log.txt > log_copy.txt and then read log_copy.txt file in any text editor...

In UNIX use command "cat":

cat log.txt > log_copy.txt

11 comments |    | Score: 1