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StackOverflow lightning talk
Below is a short presentation which hopefully I will give later today about Stack Overflow to the Transylvania JUG: Lightning talk about stackoverflow View more Microsoft Word documents from cdman83. Update: the presentation went well (IMHO) and hopefully it will add a few more people to the StackOverflow userbase. Funny thing though: you know the…
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Hidden Java concurrency bugs
Question: how can the following line of Java code throw the exception shown below? priv.addAll(common); Exception in thread "Thread-1" java.lang.ArrayIndexOutOfBoundsException at java.lang.System.arraycopy(Native Method) at java.util.ArrayList.toArray(Unknown Source) at java.util.ArrayList.addAll(Unknown Source) at TestConcurrentList$ConsumeThread.run(TestConcurrentList.java:34) Answer: because of bad synchronization. The scenario is the following: one thread is continuously modifying the list “common” while the second thread tries to…
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GFI LanGuard review
Disclaimer: I never worked as a professional network admin and all my experience was gathered in small testing environments. Also, I received a 12 month evaluation key from GFI for the purpose of writing this review, however aside from the key, I didn’t receive any form of compensation from anyone for writing this review. As…
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Pidgin/Yahoo issues
It seems that Yahoo has dropped support for legacy way of login, causing some problems with Pidgin. Possible solutions: Update to version 2.5.7 (works for me :-)) Accounts -> Edit account (to yahoo account) -> Advanced -> and to Pager Server erase “scs.msg.yahoo.com” and put instead 66.163.181.189 Further info: The bug on Launchpad – also…
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Java tips&tricks
A couple of quick/short Java tips: The Collections.unmodifiable* just wrap the original object in a facade class which throws UnsupportedOperationException when you invoke operations that would modify it (like add or remove), but the original collection still remains mutable (and the mutations are reflected in facade object). This might be obvious to some, but not…
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Comparing CVS revision numbers with Perl
Update: see a faster version here. However, make sure that you’ve nailed the problem down before starting to optimize. (The profiler is your friend) The code below was only lightly tested and isn’t all that efficient, so use it at your own risk. It returns –1 is the first version is smaller, 1 if it…
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Quirky Perl tricks
Perl is like a sharp knife: you can do a lot of things with it easily (like carve wood), but you easily hurt yourself. So here are some quirky things which I discovered (credit goes to my friends who came to me with these issues and helped me to grow my knowledge by researching the…
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Removing features is the best defense
When I’ve read the news that Microsoft is disabling Autorun for removable media other than CD/DVD in Windows 7 (and maybe HD-DVD/BlueRay) I said: cool! This will slow down the spreading of malware using this feature (on a very long timeframe of course, because Windows 7 isn’t even final yet – and far away from…
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Is Java slower than C? (and does it matter?)
Via daniel’s blog (the creator of curl) I arrived to this page: why the Java implementation (JGit) doesn’t run nearly as fast as the C implementation. The short version of it is: even after many tunings JGit is twice as slow as the C implementation. One of the problems which got my attention, was the…
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Weird RVRD issue explained
Dear reader. This is a highly specific description of a problem related to the Tibco RV (Rendezvous) product and chances are that it is of no interest to you. If this is the case, feel free to skip it. I’ve wanted to document it here, so that other people searching about this problem can find…