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Migrate Log4j 2.x to SLF4J 1.x

org.openrewrite.java.logging.slf4j.Log4j2ToSlf4j1

Transforms usages of Log4j 2.x to leveraging SLF4J 1.x directly. Note, this currently does not modify log4j.properties files.

Tags​

  • slf4j
  • logging
  • log4j

Recipe source​

GitHub, Issue Tracker, Maven Central

info

This recipe is composed of more than one recipe. If you want to customize the set of recipes this is composed of, you can find and copy the GitHub source for the recipe from the link above.

This recipe is available under the Moderne Source Available License.

Definition​

Examples​

Example 1​
Before​
import org.apache.logging.log4j.Logger;

class Test {
    static void method(Logger logger) {
        logger.fatal("uh oh");
    }
}
After​
import org.slf4j.Logger;

class Test {
    static void method(Logger logger) {
        logger.error("uh oh");
    }
}
Example 2​
Before​
import org.apache.logging.log4j.Logger;

class Test {
    static void method(Logger logger) {
        logger.fatal("uh oh");
    }
}
After​
import org.slf4j.Logger;

class Test {
    static void method(Logger logger) {
        logger.error("uh oh");
    }
}

Usage​

This recipe has no required configuration options. It can be activated by adding a dependency on org.openrewrite.recipe:rewrite-logging-frameworks in your build file or by running a shell command (in which case no build changes are needed):

  1. Add the following to your build.gradle file:
build.gradle
plugins {
    id("org.openrewrite.rewrite") version("7.7.0")
}

rewrite {
    activeRecipe("org.openrewrite.java.logging.slf4j.Log4j2ToSlf4j1")
    setExportDatatables(true)
}

repositories {
    mavenCentral()
}

dependencies {
    rewrite("org.openrewrite.recipe:rewrite-logging-frameworks:3.9.0")
}
  1. Run gradle rewriteRun to run the recipe.

See how this recipe works across multiple open-source repositories​

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Data Tables​

Source files that had results​

org.openrewrite.table.SourcesFileResults

Source files that were modified by the recipe run.

Column NameDescription
Source path before the runThe source path of the file before the run. null when a source file was created during the run.
Source path after the runA 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 changesIn 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 changesThe specific recipe that made a change.
Estimated time savingAn estimated effort that a developer to fix manually instead of using this recipe, in unit of seconds.
CycleThe recipe cycle in which the change was made.

Contributors​

Aaron Gershman, Knut Wannheden, Patrick, Tim te Beek, Sam Snyder, Md Riyazul Islam, Jonathan Schnéider, Andrii Rodionov, Adriano Machado, Laurens Westerlaken