Since Checkstyle 5.0
Checks that there are no static import statements.
Rationale: Importing static members can lead to naming conflicts between class' members. It may lead to poor code readability since it may no longer be clear what class a member resides in (without looking at the import statement).
If you exclude a starred import on a class this automatically excludes each member individually.
For example: Excluding java.lang.Math.*
. will allow the
import of each static member in the Math class
individually like java.lang.Math.PI, java.lang.Math.cos, ...
.
name | description | type | default value | since |
---|---|---|---|---|
excludes | Control whether to allow for certain classes via a star notation to be excluded such as java.lang.Math.* or specific static members to be excluded like java.lang.System.out for a variable or java.lang.Math.random for a method. See notes section for details. |
String[] | {} |
5.0 |
To configure the check:
<module name="Checker"> <module name="TreeWalker"> <module name="AvoidStaticImport"/> </module> </module>
Example:
import static java.lang.Math.pow; // violation import static java.lang.System.*; // violation import java.io.File; // OK import java.util.*; // OK
To configure the check so that the java.lang.System.out
member and all members from java.lang.Math
are allowed:
<module name="Checker"> <module name="TreeWalker"> <module name="AvoidStaticImport"> <property name="excludes" value="java.lang.System.out,java.lang.Math.*"/> </module> </module> </module>
Example:
import static java.lang.Math.*; // OK import static java.lang.System.out; // OK import static java.lang.Integer.parseInt; // violation import java.io.*; // OK import java.util.*; // OK
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
com.puppycrawl.tools.checkstyle.checks.imports