“kotlin-kapt”与“annotationProcessor()”？

Question

What is the basic core difference between:

• kotlin-kapt
• annotationProcessor()

Also, what's the working behavior of these in Kotlin/Java ?

I researched a lot about this topic but I'm a little bit confused. So, I need to learn more to clear my concepts.

Answer 1

• kapt : Default annotation processor for Kotlin projects, useful to reference generated code at compile time in a kotlin project. In order to use it you should use the kotlin-kapt plugin. It also takes care of java classes

plugins {
    kotlin("kapt") version "1.7.10"
}

and the related dependency:

dependencies {
    kapt("groupId:artifactId:version")
}

• annotationProcessor : gradle directive to specify your own annotationProcessor or a third party one. For example, in the old android projects was common to use Butterknife library that has its own annotation processor:

dependencies {
  annotationProcessor 'com.jakewharton:butterknife-compiler:10.2.3'
}

In general, an annotation processor is useful to generate code automatically from annotations (for butternife, for example @BindView ) and this is true both for kapt and for a random third-party annotation processor.