Since Gradle 4.x, there are new recommendations for dependencies.
Compile is deprecated
Configuration 'compile' is obsolete and has been replaced with 'implementation'
Annotation processor is deprecated
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.
jetified-classindex-3.4.jar (org.atteo.classindex:classindex:3.4)
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.
Since Gradle 4.x, there are new recommendations for dependencies.
Compile is deprecated
Annotation processor is deprecated