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Why is a ConcurrentModificationException thrown and how to debug it
... (a HashMap used indirectly by the JPA, it so happens), but apparently randomly the code throws a ConcurrentModificationException . What is causing it and how do I fix this problem? By using some synchronization, perhaps?
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Use JNI instead of JNA to call native code?
...m java to c. In this case jni will win in performance because you can keep and modify this buffer in c, without copying.
These are the problems I've encountered. Maybe there's more. But in general performance is not that different between jna and jni, so wherever you can use JNA, use it.
EDIT
Th...
Is asynchronous jdbc call possible?
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I don't understand how any of the proposed approaches that wrap JDBC calls in Actors, executors or anything else can help here - can someone clarify.
Surely the basic problem is that the JDBC operations block on socket IO. When it does thi...
Stock ticker symbol lookup API [closed]
...hat just offers a simple symbol lookup service? i.e., input a company name and it will tell you the ticker symbol? I've tried just screen-scraping Google Finance, but after a little while it rate limits you and you have to enter a CAPTCHA. I'm trying to batch-lookup about 2000 ticker symbols. Any id...
Alternatives to gprof [closed]
...used in the presence of mutual recursion. But the visualizer is very nice and light years ahead of gprof.
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When should static_cast, dynamic_cast, const_cast and reinterpret_cast be used?
...cit conversions between types (such as int to float, or pointer to void*), and it can also call explicit conversion functions (or implicit ones). In many cases, explicitly stating static_cast isn't necessary, but it's important to note that the T(something) syntax is equivalent to (T)something and s...
Scalar vs. primitive data type - are they the same thing?
...ticles I have read, there are sometimes references to primitive data types and sometimes there are references to scalars.
7...
Copy file or directories recursively in Python
Python seems to have functions for copying files (e.g. shutil.copy ) and functions for copying directories (e.g. shutil.copytree ) but I haven't found any function that handles both. Sure, it's trivial to check whether you want to copy a file or a directory, but it seems like a strange omission.
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Better way to shuffle two numpy arrays in unison
...o sequences of the same length results in the same number of calls to the random number generator, and these are the only "random" elements in the shuffle algorithm. By resetting the state, you ensure that the calls to the random number generator will give the same results in the second call to shu...
Explicitly calling return in a function or not
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Question was: Why is not (explicitly) calling return faster or better, and thus preferable?
There is no statement in R documentation making such an assumption.
The main page ?'function' says:
function( arglist ) expr
return(value)
Is it faster without calling return?
Both function() and re...