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what is the difference between ?:, ?! and ?= in regex?
...ng the pure regular expression. Perhaps I can but I would have to rely on callback functions.
– Y. Yoshii
May 16 '18 at 7:17
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Confusion: @NotNull vs. @Column(nullable = false) with JPA and Hibernate
...ts, but in most situations should correspond to them).
You should additionally use the JPA annotation like @Column(nullable = false) to give the jpa provider hints to generate the right DDL for creating table columns with the database constraints you want. If you can or want to rely on a JPA provi...
What's the difference between a Future and a Promise?
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According to this discussion, Promise has finally been called CompletableFuture for inclusion in Java 8, and its javadoc explains:
A Future that may be explicitly completed (setting its value and status), and may be used as a CompletionStage, supporting dependent fu...
Python: Select subset from list based on index set
I have several lists having all the same number of entries (each specifying an object property):
5 Answers
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Difference between a Seq and a List in Scala
...tional programming. However, it has limitations and it's inadequate for parallel programming. These days, Vector is a better choice than List, but habit is hard to break.
Seq is a good generalization for sequences, so if you program to interfaces, you should use that. Note that there are actually t...
Rails respond_with: how does it work?
...it works (what options you can use, etc) or point me to the place it's actually implemented so I can peruse the code on my own?
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Difference between 'struct' and 'typedef struct' in C++?
...struct Foo x;
Any time you want to refer to a Foo, you'd always have to call it a struct Foo. This gets annoying fast, so you can add a typedef:
struct Foo { ... };
typedef struct Foo Foo;
Now struct Foo (in the tag namespace) and just plain Foo (in the ordinary identifier namespace) both refe...
Floating elements within a div, floats outside of div. Why?
...t, and poorly implemented piece of technology. In fact, this reasoning actually explains a lot of html/css quirks you've no doubt encountered since you made this post.
– Slight
Apr 23 '15 at 16:01
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What are Transient and Volatile Modifiers?
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Actually, the JLS permits static and transient to be used together. The problem is it makes little sense, because typical serialization mechanisms don't persist statics anyway.
– Stephen C
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What is array to pointer decay?
... decay doesn't happen.
If you're passing an array by value, what you're really doing is copying a pointer - a pointer to the array's first element is copied to the parameter (whose type should also be a pointer the array element's type). This works due to array's decaying nature; once decayed, size...