Remove unused imports

org.openrewrite.java.RemoveUnusedImports

Remove imports for types that are not referenced. As a precaution against incorrect changes no imports will be removed from any source where unknown types are referenced. The most common cause of unknown types is the use of annotation processors not supported by OpenRewrite, such as lombok.

Tags

• RSPEC-S1128

Recipe source

GitHub, Issue Tracker, Maven Central

This recipe is available under the Apache License Version 2.0.

Usage

This recipe has no required configuration parameters and comes from a rewrite core library. It can be activated directly without adding any dependencies.

Gradle

1. Add the following to your build.gradle file:

build.gradle

plugins {
    id("org.openrewrite.rewrite") version("7.6.2")
}

rewrite {
    activeRecipe("org.openrewrite.java.RemoveUnusedImports")
    setExportDatatables(true)
}

repositories {
    mavenCentral()
}

2. Run gradle rewriteRun to run the recipe.

Gradle init script

1. Create a file named init.gradle in the root of your project.

init.gradle

initscript {
    repositories {
        maven { url "https://plugins.gradle.org/m2" }
    }
    dependencies { classpath("org.openrewrite:plugin:latest.release") }
}
rootProject {
    plugins.apply(org.openrewrite.gradle.RewritePlugin)
    dependencies {
        rewrite("org.openrewrite:rewrite-java")
    }
    rewrite {
        activeRecipe("org.openrewrite.java.RemoveUnusedImports")
        setExportDatatables(true)
    }
    afterEvaluate {
        if (repositories.isEmpty()) {
            repositories {
                mavenCentral()
            }
        }
    }
}

2. Run the recipe.

shell

gradle --init-script init.gradle rewriteRun

Maven POM

1. Add the following to your pom.xml file:

pom.xml

<project>
  <build>
    <plugins>
      <plugin>
        <groupId>org.openrewrite.maven</groupId>
        <artifactId>rewrite-maven-plugin</artifactId>
        <version>6.9.0</version>
        <configuration>
          <exportDatatables>true</exportDatatables>
          <activeRecipes>
            <recipe>org.openrewrite.java.RemoveUnusedImports</recipe>
          </activeRecipes>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

2. Run mvn rewrite:run to run the recipe.

Maven Command Line

You will need to have Maven installed on your machine before you can run the following command.

shell

mvn -U org.openrewrite.maven:rewrite-maven-plugin:run -Drewrite.activeRecipes=org.openrewrite.java.RemoveUnusedImports -Drewrite.exportDatatables=true

Moderne CLI

You will need to have configured the Moderne CLI on your machine before you can run the following command.

shell

mod run . --recipe RemoveUnusedImports

If the recipe is not available locally, then you can install it using:

mod config recipes jar install org.openrewrite:rewrite-java:8.53.0

See how this recipe works across multiple open-source repositories

Run this recipe on OSS repos at scale with the Moderne SaaS.

Run this recipe here

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Please contact Moderne for more information about safely running the recipes on your own codebase in a private SaaS.

Data Tables

SourcesFileResults

Source files that had results

org.openrewrite.table.SourcesFileResults

Source files that were modified by the recipe run.

Column Name	Description
Source path before the run	The source path of the file before the run. null when a source file was created during the run.
Source path after the run	A recipe may modify the source path. This is the path after the run. null when a source file was deleted during the run.
Parent of the recipe that made changes	In a hierarchical recipe, the parent of the recipe that made a change. Empty if this is the root of a hierarchy or if the recipe is not hierarchical at all.
Recipe that made changes	The specific recipe that made a change.
Estimated time saving	An estimated effort that a developer to fix manually instead of using this recipe, in unit of seconds.
Cycle	The recipe cycle in which the change was made.

SourcesFileErrors

Source files that errored on a recipe

org.openrewrite.table.SourcesFileErrors

The details of all errors produced by a recipe run.

Column Name	Description
Source path	The file that failed to parse.
Recipe that made changes	The specific recipe that made a change.
Stack trace	The stack trace of the failure.

RecipeRunStats

Recipe performance

org.openrewrite.table.RecipeRunStats

Statistics used in analyzing the performance of recipes.

Column Name	Description
The recipe	The recipe whose stats are being measured both individually and cumulatively.
Source file count	The number of source files the recipe ran over.
Source file changed count	The number of source files which were changed in the recipe run. Includes files created, deleted, and edited.
Cumulative scanning time (ns)	The total time spent across the scanning phase of this recipe.
99th percentile scanning time (ns)	99 out of 100 scans completed in this amount of time.
Max scanning time (ns)	The max time scanning any one source file.
Cumulative edit time (ns)	The total time spent across the editing phase of this recipe.
99th percentile edit time (ns)	99 out of 100 edits completed in this amount of time.
Max edit time (ns)	The max time editing any one source file.

Contributors

Jonathan Schneider, Tim te Beek, Laurens Westerlaken, Thomas Zub, tclayton-newr, Greg Adams, traceyyoshima, Knut Wannheden, Patrick Way, Tyler Van Gorder, Scott Jungling, Sam Snyder, Aaron Gershman, Greg Oledzki