Shortening System.out - which is better? [closed]

Question

Oftentimes people will shorten System.out to just out and make an analog called in (e.g. Scanner in = new Scanner(System.in);). I've seen two methods of doing this

Method 1:

import static java.lang.System.out;

Method 2:

static final PrintStream out = System.out;

Is there a coding convention or best practices for this? If so, which one is it and why is it more readable?

Answer 1

With the second approach you hide that out refers to System.out, so if anytime later you want to redirect the output, you need to change only static final PrintStream out = System.out; since the rest of the code is only aware of the fact that it is writing to a PrintStream.

The first approach is just using the shortcut offered by static imports.

Which one to use depends on the purpose of the code. If it is a one time, throwaway code trying out something, then I'd go with the first, otherwise the second, if there are many print statements. Otherwise I would not care replacing System.out.

On the other hand I would consider using a logger instead of System.out and that could be redirected to System.out to a File and to many other targets.

Answer 2

Is one more readable than the other or is it just a matter of personal preference?

Well, depends on your goals. I do not like both of them, so I would answer no to the first part.
Static imports will confuse readers without some IDE, because it is very hard to find out the origin of the statement. A member or class variable could be ok if you do not modify anything about System.*, but I do not see the point to save a System. (Anyway, you could have the same argument as for Method1.)
Not that heavy arguments, more a matter of personal preference. This is the reason i used the word like in the beginning. I prefer System.out(.prinln()).
One difference between this two methods is the effect of System.setOut(). Method1 is affected, Method2 does not care.

To emphasize it (it was already touched by Andras):

Method 3:

• static void print(Object object) { some implementation, e.g. System.out.println(o) }

This is clearly shorter and more flexible. If you need more you could choose any of the available logging possibilities.

(Just for completeness: This flexibility could be reached with the other methods, too. Method1: Static import of some custom class with a public class variable out which has the necessary methods. Method2: Modify the variable type to a custom class with the same public class variable out which has the necessary methods)