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Fastest way to determine if an integer's square root is an integer
...the classical way.
// The correctness is not trivial as the conversion from long to double is lossy!
final long tst = (long) Math.sqrt(x);
return tst * tst == x;
}
The first test catches most non-squares quickly. It uses a 64-item table packed in a long, so there's no array access cost ...
What is a covariant return type?
...
From the release of JDK 1.5, covariant types were introduced in Java. and I'll explain it to you with a simple case, : When we override a function the function is allowed to make changes to it's behaviour that's what you get ...
What Makes a Method Thread-safe? What are the rules?
...ly not. You can write a program with only a single local variable accessed from a single thread that is nevertheless not threadsafe:
https://stackoverflow.com/a/8883117/88656
Does that apply for static methods as well?
Absolutely not.
One answer, provided by @Cybis, was: "Local variables ...
Why is my Spring @Autowired field null?
... top of your answer that explains that retrieving the first bean, the root from which you do everything, should be done through the ApplicationContext. Some users (for which I've closed as duplicates) don't understand this.
– Sotirios Delimanolis
Oct 18 '14 at ...
Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize
... has been removed. The reason is that the permanent generation was removed from the hotspot heap and was moved to native memory.
So in order to remove this message
edit MAVEN_OPTS Environment User Variable:
Java 7
MAVEN_OPTS -Xmx512m -XX:MaxPermSize=128m
Java 8
MAVEN_OPTS -Xmx512m
...
General guidelines to avoid memory leaks in C++ [closed]
...the most basic pattern to know is RAII.
Learn to use smart pointers, both from boost, TR1 or even the lowly (but often efficient enough) auto_ptr (but you must know its limitations).
RAII is the basis of both exception safety and resource disposal in C++, and no other pattern (sandwich, etc.) will...
How to tell if a tag failed to load
...it should be ok to only support this on next gen browsers for KISS IMHO).
From the spec:
If the src attribute's value is the
empty string or if it could not be
resolved, then the user agent must
queue a task to fire a simple event
named error at the element, and
abort these steps.
~...
angularJS: How to call child scope function in parent scope
How can call a method defined in child scope from its parent scope?
4 Answers
4
...
Python __call__ special method practical example
...e to use the functions in a similar fashion to the hashlib.foo functions:
from filehash import sha1
print sha1('somefile.txt')
Of course I could have implemented it a different way, but in this case it seemed like a simple approach.
...
What is a dependency property?
...dency property in .Net (especially in WPF context). What is the difference from the regular property?
3 Answers
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