Description

Checks for redundant import statements. An import statement is considered redundant if:

• It is a duplicate of another import. This is, when a class is imported more than once.
• The class non-statically imported is from the java.lang package, e.g. importing java.lang.String.
• The class non-statically imported is from the same package as the current package.

Examples

To configure the check:

<module name="Checker">
  <module name="TreeWalker">
    <module name="RedundantImport"/>
  </module>
</module>
        

Example:

import static com.puppycrawl.tools.checkstyle.checks.imports.redundantimport.Example1.*; // OK, static import
import static java.lang.Integer.MAX_VALUE; // OK, static import

// violation below, 'Redundant import from the same package'
import com.puppycrawl.tools.checkstyle.checks.imports.redundantimport.Example1;
import java.lang.String; // violation, "Redundant import from the java.lang package"
import java.util.Scanner;
import java.util.Scanner; // violation 'Duplicate import to line 18 - java.util.Scanner'

public class Example1{ }
        

Example of Usage

• Sun Style
• Checkstyle Style

Violation Messages

• import.duplicate
• import.lang
• import.same

All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.

Package

com.puppycrawl.tools.checkstyle.checks.imports

Parent Module

TreeWalker