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What causes javac to issue the “uses unchecked or unsafe operations” warning
...icit about types, in one way or another.
For example. the code ArrayList foo = new ArrayList(); triggers that warning because javac is looking for ArrayList<String> foo = new ArrayList<String>();
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Possible heap pollution via varargs parameter
...
When you declare
public static <T> void foo(List<T>... bar) the compiler converts it to
public static <T> void foo(List<T>[] bar) then to
public static void foo(List[] bar)
The danger then arises that you'll mistakenly assign incorrect values i...
How do I see a C/C++ source file after preprocessing in Visual Studio?
...hich is sent
to the standard output.
So you can just run:
gcc -E foo.c
If you can't find such an option, you can also just find the C preprocessor on your machine. It's usually called cpp and is probably already in your path. Invoke it like this:
cpp foo.c
If there are headers you n...
Why doesn't Java allow generic subclasses of Throwable?
...lowing code:
try
{
doSomethingThatCanThrow();
}
catch (MyException<Foo> e)
{
// handle it
}
As you note, parameterization is just syntactic sugar. However, the compiler tries to ensure that parameterization remains consistent across all references to an object in compilation scope. ...
Is there a CSS selector by class prefix?
...ch the following element, which may be undesirable:
<div id='D' class='foo-class foo-status-bar bar-class'></div>
If you can ensure that such a scenario will never happen, then you are free to use such a selector for the sake of simplicity. However, the combination above is much more ...
What does the “===” operator do in Ruby? [duplicate]
...ourtytwo' # => false
/ell/ === 'Hello' # => true
/ell/ === 'Foobar' # => false
The main usage for the === operator is in case expressions, since
case foo
when bar
baz
when quux
flurb
else
blarf
end
gets translated to something (roughly) like
_temp = foo
if bar === _...
How can I create a Makefile for C projects with SRC, OBJ, and BIN subdirectories?
...d executables instead of stopping at objects, and
the name of the target (foo.o) is not what the rule will actually produce (obj/foo.o).
I suggest the following:
OBJECTS := $(SOURCES:$(SRCDIR)/%.c=$(OBJDIR)/%.o)
$(OBJECTS): $(OBJDIR)/%.o : $(SRCDIR)/%.c
$(CC) $(CFLAGS) -c $< -o $@
@...
Is it possible to GROUP BY multiple columns using MySQL?
...
@ypercubeᵀᴹ oops, stupidly I was thinking "group by foo, bar" behaved like "... group by foo union ... group by bar". It would be an unusual case indeed to GROUP BY CONCAT.
– Abram
May 18 '17 at 21:06
...
How can I fill out a Python string with spaces?
...f python 3.6 it's even more convenient with literal string interpolation!
foo = 'foobar'
print(f'{foo:10} is great!')
# foobar is great!
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What's Mongoose error Cast to ObjectId failed for value XXX at path “_id”?
...that it can properly query for the matching doc. This is an ObjectId but "foo" is not a valid ObjectId so the cast fails.
This doesn't happen with 41224d776a326fb40f000001 because that string is a valid ObjectId.
One way to resolve this is to add a check prior to your findById call to see if id i...