Oct 9, 2012 · indeed, it isn't compile-time constant. However, the definition "In computer programming, a constant is a value that cannot be altered by the program during normal execution, i.e., the value is constant" does not strictly require it being compile-time constant, but a run-time one, so this answer is still correct. –

Sep 16, 2008 · The Java compiler will actually optimize this and place the actual value of the constant into any class that references it. If you later change the 'Constants' class and you don't do a hard re-compile on other classes that reference that class, you will wind up with a combination of old and new values being used.

IIRC, one item in effective Java (2nd Ed) has enum constants enumerating standard options implementing a [Java keyword] interface for any value. My preference is to use a [Java keyword] interface over a final class for constants. You implicitly get the public static final.

Mar 28, 2018 · The reason for that is because Java creates copies of non static variables every time you instantiate an object of the class. So if we make the constants static it would not do so and would save memory. With final we can make the variable constant. Hence the best practice to define a constant variable is the following:

Sep 21, 2012 · Many of these naming conventions were created well before IDEs were in widespread use. These days, static constants are going to be colored differently than local variables, so the need to use a specific naming convention to identify them is greatly reduced.

1 - The constant expression restrictions can be summarized as follows. Constant expressions a) can use primitive types and String only, b) allow primaries that are literals (apart from null) and constant variables only, c) allow constant expressions possibly parenthesised as subexpressions, d) allow operators except for assignment operators, ++, - …

If a constant is not static, Java will allocate a memory for that constant in every object of the class (i.e., one copy of the constant per object). If a constant is static, there will be only one copy of the constant for that class (i.e., one copy per class). Therefore, if the constant has only one value, it should declared static.

How to declare a constant in Java? 1. Using "Constant" Objects in Java. 65. Morbid use of constants. 3.

Oct 14, 2015 · I mean the array components be constants i.e. a[0] be a constant variable like this public static final int SIZE = 10; You cannot give array indexes names. You could initialize an array using the values of pre-existing constants:

Apr 17, 2010 · Joshua Bloch, "Effective Java - Programming Language Guide": The constant interface pattern is a poor use of interfaces. That a class uses some constants internally is an implementation detail. Implementing a constant interface causes this implementation detail to leak into the class's exported API.