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Why doesn't ruby support method overloading?
...; end; # second argument has a default value
method(10)
# Now the method call can match the first one as well as the second one,
# so here is the problem.
So ruby needs to maintain one method in the method look up chain with a unique name.
...
What's the difference between session.persist() and session.save() in Hibernate?
...also guarantees that it will
not execute an INSERT statement if it
is called outside of transaction
boundaries. This is useful in
long-running conversations with an
extended Session/persistence context.
A method like persist() is required.
save() does not guarantee the same, it...
Implicit type conversion rules in C++ operators
...s int. So short/char are promoted to int before the operation is done.
In all your expressions the int is promoted to a float before the operation is performed. The result of the operation is a float.
int + float => float + float = float
int * float => float * float = float
float * int =&g...
Deep copying an NSArray
Is there any built-in function that allows me to deep copy an NSMutableArray ?
6 Answers
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Check Whether a User Exists
...t, you got command return value ($?)1
And as other answers pointed out: if all you want is just to check if the user exists, use if with id directly, as if already checks for the exit code. There's no need to fiddle with strings, [, $? or $():
if id "$1" &>/dev/null; then
echo 'user found...
What does Serializable mean?
...it is an interface that if implemented in a class, this class can automatically be serialized and deserialized by different serializers.
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Elegant way to check for missing packages and install them?
...em are novice/intermediate R users and don't realize that they have to install packages they don't already have.
29 Answers...
JPA OneToMany not deleting child
...em with a simple @OneToMany mapping between a parent and a child entity. All works well, only that child records are not deleted when I remove them from the collection.
...
how can you easily check if access is denied for a file in .NET?
Basically, I would like to check if I have rights to open the file before I actually try to open it; I do not want to use a try/catch for this check unless I have to. Is there a file access property I can check before hand?
...
Java Date cut off time information
...uitive way to work with dates and times. For instance you can convert trivially between (say) LocalDateTime and LocalDate objects.
e.g. (to illustrate the API)
LocalDate date = new LocalDateTime(milliseconds).toLocalDate()
Additionally it solves some thread-safety issues with date/time formatter...