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Java null check why use == instead of .equals()
... to see if two objects are equal according to their contract for what equality means. It's entirely possible for two distinct object instances to be "equal" according to their contract. And then there's the minor detail that since equals is a method, if you try to invoke it on a null reference, you'...
Is Tomcat running?
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Why grep ps, when the pid has been written to the $CATALINA_PID file?
I have a cron'd checker script which sends out an email when tomcat is down:
kill -0 `cat $CATALINA_PID` > /dev/null 2>&1
if [ $? -gt 0 ]
then
echo "Check tomcat" | mailx -s "T...
Internal Error 500 Apache, but nothing in the logs?
...sed to the scripts error logs usually has the (more) specific error. often it will be permissions denied or even an interpreter that can't be found.
This means the fault almost always lies with your script. e.g you uploaded a perl script but didnt give it execute permissions? or perhaps it was corr...
How can I sort arrays and data in PHP?
...erely whether key-value associations are kept (the "a" functions), whether it sorts low-to-high or reverse ("r"), whether it sorts values or keys ("k") and how it compares values ("nat" vs. normal). See http://php.net/manual/en/array.sorting.php for an overview and links to further details.
Multi di...
Git: How to rebase to a specific commit?
I'd like to rebase to a specific commit, not to a HEAD of the other branch:
9 Answers
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error: ‘NULL’ was not declared in this scope
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NULL is not a keyword. It's an identifier defined in some standard headers. You can include
#include <cstddef>
To have it in scope, including some other basics, like std::size_t.
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Share cookie between subdomain and domain
... questions. I understand that if I specify the domain as .mydomain.com (with the leading dot) in the cookie that all subdomains can share a cookie.
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In-place type conversion of a NumPy array
Given a NumPy array of int32 , how do I convert it to float32 in place ? So basically, I would like to do
6 Answers
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Why use Abstract Base Classes in Python?
... implemented classes.
Long version
There is a contract between a class and its callers. The class promises to do certain things and have certain properties.
There are different levels to the contract.
At a very low level, the contract might include the name of a method or its number of parameters.
I...
Repository Pattern Step by Step Explanation [closed]
Can someone please explain to me the Repository Pattern in .NET, step by step giving a very simple example or demo.
2 Answe...