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Package objects
...se the nested package syntax but that is quite unusual.
The main use case for package objects is when you need definitions in various places inside your package as well as outside the package when you use the API defined by the package. Here is an example:
// file: foo/bar/package.scala
package f...
Why does String.valueOf(null) throw a NullPointerException?
...method invocation, it is necessary to choose one to provide the descriptor for the run-time method dispatch. The Java programming language uses the rule that the most specific method is chosen.
A char[] is-an Object, but not all Object is-a char[]. Therefore, char[] is more specific than Object, a...
Actual meaning of 'shell=True' in subprocess
...
So invoking the shell invokes a program of the user's choosing and is platform-dependent. Generally speaking, avoid invocations via the shell.
Invoking via the shell does allow you to expand environment variables and file globs according to the shell's usual mechanism. On POSIX systems, the shel...
Merging two images in C#/.NET
...ve(/*somekindofpath*/,
System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch (Exception ex) { }
}
}
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makefile execute another target
... you want to impose a specific ordering on the rules to be invoked without forcing the target to be updated if one of those rules is executed. In that case, you want to define order-only prerequisites. Order-only prerequisites can be specified by placing a pipe symbol (|) in the prerequisites list: ...
File path to resource in our war/WEB-INF folder?
...t you can read a file from there in a servlet context. I don't know how to form the path to the resource though:
3 Answers
...
Regex expressions in Java, \\s vs. \\s+
...espaces. They're the so-called regular expression quantifiers, and they perform matches like this (taken from the documentation):
Greedy quantifiers
X? X, once or not at all
X* X, zero or more times
X+ X, one or more times
X{n} X, exactly n times
X{n,} X, at least n times
X{n,m} X, at leas...
SQL Logic Operator Precedence: And and Or
...ect Case When (@x=1 OR @y=1) And @z=1 Then 'T' Else 'F' End -- outputs F
For those who like to consult references (in alphabetic order):
Microsoft Transact-SQL operator precedence
Oracle MySQL 9 operator precedence
Oracle 10g condition precedence
PostgreSQL operator Precedence
SQL as understood...
Match linebreaks - \n or \r\n?
...
Gonna answer in opposite direction.
2) For a full explanation about \r and \n I have to refer to this question, which is far more complete than I will post here: Difference between \n and \r?
Long story short, Linux uses \n for a new-line, Windows \r\n and old Ma...
Why is it wrong to use std::auto_ptr with standard containers?
...ically independent. std::auto_ptr does not fulfill this requirement.
Take for example this code:
class X
{
};
std::vector<std::auto_ptr<X> > vecX;
vecX.push_back(new X);
std::auto_ptr<X> pX = vecX[0]; // vecX[0] is assigned NULL.
To overcome this limitation, you should use t...