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Why doesn't the example compile, aka how does (co-, contra-, and in-) variance work?
...ng the wrong direction. Interestingly enough, we could solve this problem by making List contravariant in A, but then the return type List[A] would be invalid as the cons function expects its return type to be covariant.
Our only two options here are to a) make A invariant, losing the nice, intuit...
HTTP headers in Websockets client API
...WebSockets API, but it seems they are just developing the API on an island by itself.
– eleotlecram
May 1 '12 at 14:26
4
...
symbolic link: find all files that link to this file
...urse, as any of the files pointing to foo.txt may themselves be pointed-at by some other links... ex: A->B->foo.txt, /tmp/C->B->foo.txt, etc.
– Olivier Dulac
Nov 7 '13 at 17:31
...
Hibernate throws org.hibernate.AnnotationException: No identifier specified for entity: com..domain.
....
Using a wrapper type is a better choice when using Hibernate because, by checking if the id is null or not, Hibernate can better determine if an entity is transient (it does not have an associated table row) or detached (it has an associated table row, but it's not managed by the current Persis...
Best way to test for a variable's existence in PHP; isset() is clearly broken
...h can replace all the ways isset can be used. Some use cases are addressed by other functions, while others do not stand up to scrutiny, or have dubious value beyond code golf. Far from being "broken" or "inconsistent", other use cases demonstrate why isset's reaction to null is the logical behaviou...
What are the file limits in Git (number and size)?
...mous (but inter-dependent) parts, you must use submodules.
As illustrated by Talljoe's answer, the limit can be a system one (large number of files), but if you do understand the nature of Git (about data coherency represented by its SHA-1 keys), you will realize the true "limit" is a usage one: i....
Does making a struct volatile make all its members volatile?
... involving the object
because the value of the object might
be changed by means undetectable by an
implementation. See 1.9 for detailed
semantics. In general, the semantics
of volatile are intended to be the
same in C + + as they are in C. ]
That means, if your object is an instance of...
TypeError: sequence item 0: expected string, int found
...the [,] from your second example, a list comprehension is not required and by removing them you have a generator which is more efficient.
– jamylak
Jun 4 '12 at 12:01
3
...
Function pointers, Closures, and Lambda
...e lessThan was not in scope, I would either have to manually keep it alive by passing it to each function in the chain, or by promoting it to a global.
Though most mainstream languages that support closures use anonymous functions, there is no requirement for that. You can have closures without ano...
What's the difference between @Component, @Repository & @Service annotations in Spring?
...Therefore, you can annotate your component classes with @Component,
but, by annotating them with @Repository, @Service, or @Controller
instead, your classes are more properly suited for processing by tools
or associating with aspects.
For example, these stereotype annotations
make idea...