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Spring @Transactional - isolation, propagation
...ll the second service in a separate transaction. Back to our example, this time you are concerned about the database security, so you define your DAO classes this way:
/* User DAO */
@Transactional(Propagation=MANDATORY)
class UserDAO{
// some CRUD methods
}
Meaning that whenever a DAO object, a...
What are the rules for evaluation order in Java?
...
Let me say this very clearly, because people misunderstand this all the time:
Order of evaluation of subexpressions is independent of both associativity and precedence. Associativity and precedence determine in what order the operators are executed but do not determine in what order the subexpre...
What does it mean to hydrate an object?
... Deserialization involves creating the object with the data it had at the time it was serialized. Hydration refers to how you fill an object with data. It's a subtle difference, but it is a difference. You cannot, for example, partially deserialize an object. (at least, not through any standard...
How to correctly close a feature branch in Mercurial?
...the last one.
Update: Since Mercurial 1.5 you can close the branch at any time so it will not appear in both hg branches and hg heads anymore. The only thing that could possibly annoy you is that technically the revision graph will still have one more revision without childen.
Update 2: Since Merc...
Where is Python's sys.path initialized from?
...as not found, and no registry keys were present, then the
relative compile-time value of PYTHONPATH is added; otherwise, this step is ignored.
Paths in the compile-time macro PYTHONPATH are added relative to the dynamically-found sys.prefix.
On Mac and Linux, the value of sys.exec_prefix is added. O...
ReSharper warns: “Static field in generic type”
...eof(T))
Since your probably don't want to generate a new serializer each time you need to serialize an instance of a particular type, you might add this:
public class SerializableEntity<T>
{
// ReSharper disable once StaticMemberInGenericType
private static XmlSerializer _typeSpecif...
MPICH vs OpenMPI
...conclusions. Such performance issues are usually network-specific and sometimes even machine-specific.
I have found Open-MPI to be more robust when using MacOS with a VPN, i.e. MPICH may hang in startup due to hostname resolution issues. As this is a bug, this issue may disappear in the future.
...
Undefined, unspecified and implementation-defined behavior
... bounds, dereferencing the null pointer, accessing objects after their lifetime ended or writing allegedly clever expressions like i++ + ++i.
Section 1.9 of the C++ standard also mentions undefined behavior's two less dangerous brothers, unspecified behavior and implementation-defined behavior:
The...
Should I use SVN or Git? [closed]
...
We use Git on Windows heavily and have for a long time now. Git is absolutely fantastic on Windows.
– Charlie Flowers
Feb 6 '11 at 5:18
13
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Why switch is faster than if
...s used.
The difference, in short, is that TableSwitch is done in constant time because each value within the range of possible values is given a specific byte-code offset. Thus, when you give the statement an offset of 3, it knows to jump ahead 3 to find the correct branch.
Lookup switch uses a bi...