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Stateless and Stateful Enterprise Java Beans
I am going through the Java EE 6 tutorial and I am trying to understand the difference between stateless and stateful session beans. If stateless session beans do not retain their state in between method calls, why is my program acting the way it is?
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Are static variables shared between threads?
...y the JVM's memory model. Here's an article talking about the memory model and how writes become visible to threads. You can't count on changes one thread makes becoming visible to other threads in a timely manner (actually the JVM has no obligation to make those changes visible to you at all, in an...
How should equals and hashcode be implemented when using JPA and Hibernate
How should model class's equals and hashcode be implemented in Hibernate? What are the common pitfalls? Is the default implementation good enough for most cases? Is there any sense to use business keys?
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Efficiently checking if arbitrary object is NaN in Python / numpy / pandas?
...lues. As I iterate over the data set, I need to detect such missing values and handle them in special ways.
2 Answers
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Re-doing a reverted merge in Git
...t I wanted the branch to go back to e.g. git checkout 123466t7632723. Then converted to a branch git checkout my-new-branch. I then deleted the branch I didn't want any more. Of course this will only work if you are able to throw away the branch you messed up.
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The best way to remove duplicate values from NSMutableArray in Objective-C?
... *orderedSet = [NSOrderedSet orderedSetWithArray:yourArray];
You can now convert it back to a unique NSArray
NSArray *uniqueArray = orderedSet.array;
Or just use the orderedSet because it has the same methods like an NSArray like objectAtIndex:, firstObject and so on.
A membership check with c...
JPA - Returning an auto generated id after persist()
I'm using JPA (EclipseLink) and Spring. Say I have a simple entity with an auto-generated ID:
7 Answers
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Creating an empty bitmap and drawing though canvas in Android
I'd like to create an empty bitmap and set a canvas to that bitmap and then draw any shape on the bitmap.
2 Answers
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Java Class.cast() vs. cast operator
...ce and no conversion ever happens to objects (only primitive values can be converted using this syntax).
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Does Ruby regular expression have a not match operator like “!~” in Perl?
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It's a lower-level solution. It's not always easy to convert regexps this way. On the other hand, this solution doesn't depend on top-level programming language ;)
– Konstantin
Mar 21 '18 at 12:43
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