Setting Explict Annotation Processor

Question

I am attempting to add a maven repository to my Android Studio project. When I do a Gradle project sync everything is fine. However, whenever I try to build my apk, I get this error:

Execution failed for task ':app:javaPreCompileDebug'.
> Annotation processors must be explicitly declared now.  The following dependencies on 
the compile classpath are found to contain annotation processor.  Please add them to 
the annotationProcessor configuration.
 - classindex-3.3.jar
Alternatively, set android.defaultConfig.javaCompileOptions.annotationProcessorOptions
.includeCompileClasspath = true to continue with previous behavior.  Note that this 
option is deprecated and will be removed in the future.
See https://developer.android.com/r/tools/annotation-processor-error-message.html for more details.

The link included (https://developer.android.com/r/tools/annotation-processor-error-message.html) in the error 404s so its of no help.

I have enabled annotation processing in the android studio settings, and added includeCompileClasspath = true to my Annotation Processor options. I have also tried adding classindex, classindex-3.3 and classindex-3.3.jar to Processor FQ Name, but that did not help either.

these are the lines I have added to the default build.gradle under dependecies:

dependencies {
    ...
    compile group: 'com.skadistats', name: 'clarity', version:'2.1.1'
    compile group: 'org.atteo.classindex', name: 'classindex', version:'3.3'
}

Originally I just had the "clarity" one added, because that is the one I care about, but I added the "classindex" entry in the hopes that it would fix it. Removing "clarity" and keeping "classindex" gives me the exact same error.

I'm not all too familiar with gradle/maven so any help would be appreciated.

Answer 1

To fix the error, simply change the configuration of those dependencies to use annotationProcessor. If a dependency includes components that also need to be on the compile classpath, declare that dependency a second time and use the compile dependency configuration.

For example:

annotationProcessor 'com.jakewharton:butterknife:7.0.1'
compile 'com.jakewharton:butterknife:7.0.1'

This link describes it in detail: https://developer.android.com/studio/preview/features/new-android-plugin-migration.html#annotationProcessor_config

Relevant snippet included for completeness.

Use the annotation processor dependency configuration

In previous versions of the Android plugin for Gradle, dependencies on the compile classpath were automatically added to the processor classpath. That is, you could add an annotation processor to the compile classpath and it would work as expected. However, this causes a significant impact to performance by adding a large number of unnecessary dependencies to the processor.

When using the new plugin, annotation processors must be added to the processor classpath using the annotationProcessor dependency configuration, as shown below:

dependencies { ... annotationProcessor 'com.google.dagger:dagger-compiler:' }

The plugin assumes a dependency is an annotation processor if its JAR file contains the following file: META- INF/services/javax.annotation.processing.Processor. If the plugin detects annotation processors on the compile classpath, your build fails and you get an error message that lists each annotation processor on the compile classpath. To fix the error, simply change the configuration of those dependencies to use annotationProcessor. If a dependency includes components that also need to be on the compile classpath, declare that dependency a second time and use the compile dependency configuration.