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JPA EntityManager: Why use persist() over merge()?
EntityManager.merge() can insert new objects and update existing ones.
15 Answers
15
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Quickly create large file on a Windows system
...m. By large I'm thinking 5 GB. The content doesn't matter. A built-in command or short batch file would be preferable, but I'll accept an application if there are no other easy ways.
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Why is Thread.Sleep so harmful
...it mentioned that Thread.Sleep(); should not be used, but I can't understand why this is so. If Thread.Sleep(); can cause trouble, are there any alternative solutions with the same result that would be safe?
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Rename package in Android Studio
How do you rename packages in the new IDE Android Studio, based on IntelliJ IDEA?
52 Answers
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Difference between timestamps with/without time zone in PostgreSQL
...g to the process of inserting/retrieving values. But readers should understand that both data types, timestamp with time zone and timestamp without time zone, in Postgres do *not actually store time zone information. You can confirm this with a glance at the data type doc page: Both types takes up t...
How do I measure time elapsed in Java? [duplicate]
...answers posted so far are quite right.
If you are measuring elapsed time, and you want it to be correct, you must use System.nanoTime(). You cannot use System.currentTimeMillis(), unless you don't mind your result being wrong.
The purpose of nanoTime is to measure elapsed time, and the purpose of...
Compiler Ambiguous invocation error - anonymous method and method group with Func or Action
...roup to a compatible delegate type
(emphasis added) is deeply misleading and unfortunate. I'll have a talk with Mads about getting the word "compatible" removed here.
The reason this is misleading and unfortunate is because it looks like this is calling out to section 15.2, "Delegate compatibi...
How to use OpenSSL to encrypt/decrypt files?
I want to crypt and decrypt one file using one password.
10 Answers
10
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How to create P12 certificate for iOS distribution
We have an iOS app whose push notification cert has expired and we're trying to create a new one. I've created new certs in the Provisioning portal (ios_developer.cer, ios_distribution.cer) and downloaded them. I was following instructions here on Stack Overflow to convert it to PEM and then to ...
Git Blame Commit Statistics
How can I "abuse" blame (or some better suited function, and/or in conjunction with shell commands) to give me a statistic of how much lines (of code) are currently in the repository originating from each committer?
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