Why is this an issue?

Unnecessary imports refer to importing types that are not used or referenced anywhere in the code.

Although they don’t affect the runtime behavior of the application after compilation, removing them will:

Exceptions

Imports for types mentioned in Javadocs are ignored.

How to fix it

While it’s not difficult to remove these unneeded lines manually, modern code editors support the removal of every unnecessary import with a single click from every file of the project.

Code examples

Noncompliant code example

package myapp.helpers;

import module java.logging; // Module imports are a Java 25 feature
import module java.logging; // Noncompliant - module is imported twice

import java.io.IOException;
import java.nio.file.*;
import java.nio.file.*;     // Noncompliant - package is imported twice
import java.lang.Runnable;  // Noncompliant - java.lang is imported by default

public class FileHelper {
    private static final Logger LOGGER = Logger.getLogger("FileLogger");

    public static String readFirstLine(String filePath) throws IOException {
        LOGGER.log(Level.INFO, "Reading first line from: " + filePath);
        return Files.readAllLines(Paths.get(filePath)).get(0);
    }
}

Compliant solution

package myapp.helpers;

import module java.logging;

import java.io.IOException;
import java.nio.file.*;

public class FileHelper {
    private static final Logger LOGGER = Logger.getLogger("FileLogger");

    public static String readFirstLine(String filePath) throws IOException {
        LOGGER.log(Level.INFO, "Reading first line from: " + filePath);
        return Files.readAllLines(Paths.get(filePath)).get(0);
    }
}

Resources

Documentation

Related rules