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What is the difference between up-casting and down-casting with respect to class variable
What is the difference between up-casting and down-casting with respect to class variable?
10 Answers
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Why is it bad practice to call System.gc()?
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The reason everyone always says to avoid System.gc() is that it is a pretty good indicator of fundamentally broken code. Any code that depends on it for correctness is certainly broken; any that rely on it for performance are most likely broken.
You don't know what sort of ga...
What are the benefits of Java's types erasure?
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Type Erasure Is Good
Let's stick to the facts
A lot of the answers thus far are overly concerned with the Twitter user. It's helpful to keep focused on the messages and not the messenger. There is a fairly consistent message with even j...
Is it safe to get values from a java.util.HashMap from multiple threads (no modification)?
There is a case where a map will be constructed, and once it is initialized, it will never be modified again. It will however, be accessed (via get(key) only) from multiple threads. Is it safe to use a java.util.HashMap in this way?
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INNER JOIN ON vs WHERE clause
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INNER JOIN is ANSI syntax which you should use.
It is generally considered more readable, especially when you join lots of tables.
It can also be easily replaced with an OUTER JOIN whenever a need arises.
The WHERE syntax is more rel...
Why should I use a pointer rather than the object itself?
...ave started working with objects in C++. But one thing that occurred to me is that people often use pointers to objects rather than the objects themselves, for example this declaration:
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Why is quicksort better than mergesort?
I was asked this question during an interview. They're both O(nlogn) and yet most people use Quicksort instead of Mergesort. Why is that?
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Why is unsigned integer overflow defined behavior but signed integer overflow isn't?
Unsigned integer overflow is well defined by both the C and C++ standards. For example, the C99 standard ( §6.2.5/9 ) states
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Is it possible to decrypt MD5 hashes?
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No. MD5 is not encryption (though it may be used as part of some encryption algorithms), it is a one way hash function. Much of the original data is actually "lost" as part of the transformation.
Think about this: An MD5 is always ...
What is the difference between supervised learning and unsupervised learning? [closed]
In terms of artificial intelligence and machine learning, what is the difference between supervised and unsupervised learning?
Can you provide a basic, easy explanation with an example?
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