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How to install JSTL? The absolute uri: http://java.sun.com/jstl/core cannot be resolved
... users. The problem with Tomcat is that it does not offer JSTL out the box and thus you have to manually install it. This is not necessary in normal Java EE servers. See also What exactly is Java EE?
In your specific case, your pom.xml basically tells you that you have jstl-1.2.jar and standard-1.1...
Redis strings vs Redis hashes to represent JSON: efficiency?
...e cases):
Store the entire object as JSON-encoded string in a single key and keep track of all Objects using a set (or list, if more appropriate). For example:
INCR id:users
SET user:{id} '{"name":"Fred","age":25}'
SADD users {id}
Generally speaking, this is probably the best method in most cas...
Polymorphism vs Overriding vs Overloading
...is not definable for Humans. It is only definable for the subclasses Male and Female. Also, Human is an abstract concept — You cannot create a human that is neither Male nor Female. It’s got to be one or the other.
So we defer the implementation by using the abstract class.
public class Mal...
What should I name a table that maps two tables together? [closed]
...There are only two hard things in
Computer Science: cache invalidation
and naming things-- Phil Karlton
Coming up with a good name for a table that represents a many-to-many relationship makes the relationship easier to read and understand. Sometimes finding a great name is not trivial but usu...
What is the fastest/most efficient way to find the highest set bit (msb) in an integer in C?
If I have some integer n, and I want to know the position of the most significant bit (that is, if the least significant bit is on the right, I want to know the position of the furthest left bit that is a 1), what is the quickest/most efficient method of finding out?
...
Append a dictionary to a dictionary [duplicate]
I have two existing dictionaries, and I wish to 'append' one of them to the other. By that I mean that the key,values of the other dictionary should be made into the first dictionary. For example:
...
Understanding “randomness”
I can't get my head around this, which is more random?
28 Answers
28
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What's a concise way to check that environment variables are set in a Unix shell script?
...(an empty string) is OK — not exactly what you want, but the alternative and older notation.
The second variant (using :?) requires DEST to be set and non-empty.
If you supply no message, the shell provides a default message.
The ${var?} construct is portable back to Version 7 UNIX and the Bourne ...
Including all the jars in a directory within the Java classpath
...ion. See also: Execute jar file with multiple classpath libraries from command prompt)
Understanding Wildcards
From the Classpath document:
Class path entries can contain the basename wildcard character *, which is considered equivalent to specifying a list of all the files
in the directory with th...
Why Choose Struct Over Class?
...n many circumstances.
Structs are preferable if they are relatively small and copiable because copying is way safer than having multiple references to the same instance as happens with classes. This is especially important when passing around a variable to many classes and/or in a multithreaded env...