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System.currentTimeMillis() vs. new Date() vs. Calendar.getInstance().getTime()
In Java, what are the performance and resource implications of using
8 Answers
8
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Why do C and C++ compilers allow array lengths in function signatures when they're never enforced?
...actually ignored.
The decision to allow this syntax was made in the 1970s and has caused much confusion ever since...
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How can I check if multiplying two numbers in Java will cause an overflow?
I want to handle the special case where multiplying two numbers together causes an overflow. The code looks something like this:
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What exactly do “IB” and “UB” mean?
I've seen the terms "IB" and "UB" used several times, particularly in the context of C++. I've tried googling them, but apparently those two-letter combinations see a lot of use. :P
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What to do about Eclipse's “No repository found containing: …” error messages?
...n Linux to which I added the subversive plugins, the m2e Maven integration and the Mylin connector for Trac. For the last couple of weeks I've been trying to install updates, and every time I get back a message like
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How to amend several commits in Git to change author
I have made a series of commits in Git and I realise now that I forgot to set my user name and user email properties correctly (new machine). I have not yet pushed these commits to my repository, so how can I correct these commits before I do so (only the 3 latest commits on the master branch)?
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#define macro for debug printing in C?
...on:
#ifdef DEBUG
#define DEBUG_TEST 1
#else
#define DEBUG_TEST 0
#endif
And then use DEBUG_TEST where I used DEBUG.
If you insist on a string literal for the format string (probably a good idea anyway), you can also introduce things like __FILE__, __LINE__ and __func__ into the output, which can...
What is std::move(), and when should it be used?
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Wikipedia Page on C++11 R-value references and move constructors
In C++11, in addition to copy constructors, objects can have move constructors.
(And in addition to copy assignment operators, they have move assignment operators.)
The move constructor is used instead...
What are the disadvantages to declaring Scala case classes?
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First the good bits:
Everything immutable by default
Yes, and can even be overridden (using var) if you need it
Getters automatically defined
Possible in any class by prefixing params with val
Decent toString() implementation
Yes, very useful, but doable by hand on any class if nece...
Is it possible to make a type only movable and not copyable?
...ntation.
To answer the question you didn't ask... "what's up with moves and copy?":
Firstly I'll define two different "copies":
a byte copy, which is just shallowly copying an object byte-by-byte, not following pointers, e.g. if you have (&usize, u64), it is 16 bytes on a 64-bit computer, ...