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Why is it bad practice to call System.gc()?
...ring a 1.5GB HashMap) with System.gc() , I was told it's bad practice to call System.gc() manually, but the comments were not entirely convincing. In addition, no one seemed to dare to upvote, nor downvote my answer.
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Install a Python package into a different directory using pip?
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Use:
pip install --install-option="--prefix=$PREFIX_PATH" package_name
You might also want to use --ignore-installed to force all dependencies to be reinstalled using this new prefix. You can use --install-option to multiple times to a...
SQL Server: Examples of PIVOTing String data
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If you specifically want to use the SQL Server PIVOT function, then this should work, assuming your two original columns are called act and cmd. (Not that pretty to look at though.)
SELECT act AS 'Action', [View] as 'View', [Edit] as 'Edit...
Does Java have a HashMap with reverse lookup?
...to be one of the implementations of BidiMap.
As a mathematician, I would call this kind of structure a bijection.
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How to get the current date and time
...e();
In the words of the Javadocs for the zero-argument constructor:
Allocates a Date object and initializes it so that it represents the time at which it was allocated, measured to the nearest millisecond.
Make sure you're using java.util.Date and not java.sql.Date -- the latter doesn't hav...
How is a tag different from a branch in Git? Which should I use, here?
... development efforts on the same code base. Changes to a branch may eventually be merged back into another branch to unify them.
Usually you'll tag a particular version so that you can recreate it, e.g., this is the version we shipped to XYZ Corp. A branch is more of a strategy to provide on-goi...
Is it fine to have foreign key as primary key?
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Foreign keys are almost always "Allow Duplicates," which would make them unsuitable as Primary Keys.
Instead, find a field that uniquely identifies each record in the table, or add a new field (either an auto-incrementing integer or a GUID) to act as the p...
How can I return to a parent activity correctly?
...ent to it.
Therefore, the system is forced to recreate activity A (i.e. calling onCreate) even if the task stack is handled correctly.
To fix this problem you need to change the manifest, adding the following attribute to the A activity declaration:
android:launchMode="singleTop"
Note: calling...
SQL error “ORA-01722: invalid number”
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Also notice that manually complete a field with "(null)" will give you that error. If the defaul is null and you don't complete it will auto-complete with (null) but it is not the same when you type it.
– bogdan.rusu
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Thread vs ThreadPool
...rom the pool rather than one I've explicitly created? I'm thinking specifically of .NET here, but general examples are fine.
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