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What is a NullPointerException, and how do I fix it?
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When you declare a reference variable (i.e. an object) you are really creating a pointer to an object. Consider the following code where you declare a variable of primitive type int:
int x;
x = 10;
In this example, the variable x is an int and Java will initialize it to 0 for you. When yo...
How do you crash a JVM?
...ught that you could do so by writing an infinite for-loop that would eventually use up all the memory.
27 Answers
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How to schedule a function to run every hour on Flask?
...om apscheduler.schedulers.background import BackgroundScheduler
def print_date_time():
print(time.strftime("%A, %d. %B %Y %I:%M:%S %p"))
scheduler = BackgroundScheduler()
scheduler.add_job(func=print_date_time, trigger="interval", seconds=3)
scheduler.start()
# Shut down the scheduler when ...
Multiline bash commands in makefile
...colon:
foo:
for i in `find`; \
do \
all="$$all $$i"; \
done; \
gcc $$all
But if you just want to take the whole list returned by the find invocation and pass it to gcc, you actually don't necessarily need a multiline command:
foo:
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Best way to obfuscate an e-mail address on a website?
...domain name. My e-mail address is (my first name)@(my last name).com. So really, when it comes down to guessing it, it's not very hard.
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Android Fragment lifecycle over orientation changes
...mit();
} else {
// do nothing - fragment is recreated automatically
}
Be warned though: problems will occur if you try and access Activity Views from inside the Fragment as the lifecycles will subtly change. (Getting Views from a parent Activity from a Fragment isn't easy).
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pandas resample documentation
...ffsets), and a section about resampling.
Note that there isn't a list of all the different how options, because it can be any NumPy array function and any function that is available via groupby dispatching can be passed to how by name.
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How to check if a string is a valid date
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Using a "catch-it-all" rescue should be considered an anti-pattern. It can hide out other errors which we don't expect and make the debugging of the code extremely difficult.
– yagooar
Jan 29 '13 at 10:32...
Git push rejected after feature branch rebase
...hat remote branch can be fast-forwarded to your local branch, that is that all the difference between local and remote branches is in local having some new commits at the end like that:
Z--X--R <- origin/some-branch (can be fast-forwarded to Y commit)
\
T--Y <...
How to implement a queue using two stacks?
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Keep 2 stacks, let's call them inbox and outbox.
Enqueue:
Push the new element onto inbox
Dequeue:
If outbox is empty, refill it by popping each element from inbox and pushing it onto outbox
Pop and return the top element from outbox
Usin...