Meet "is not incremental" , when use java compile incremental feature in Android Project

I got logs like :
"is not incremental (e.g. outputs have changed, no previous execution, etc.).“
"is not incremental. Unable to infer the source directories.”

I just do this:
tasks.withType(JavaCompile) { task ->
task.options.useDepend = true
task.options.incremental = true

plus. DataBinding is also being used in my Android project.

Looks like your task does not declare the inputs and outputs - in that case, Gradle has no way of checking the timestamps and hashes, so it assumes it needs to rebuild.

But the type of the task is actually JavaCompile. You mean that I need do sth further to declare the inputs and outputs?

In that case you don’t provide enough information to answer your question. JavaCompile is surely incremental.

Incremental is a incubating feature. What information do you need to figure it out?

Incremental is a incubating feature.

Incubating or not, incremental compiling works for me and pretty much everybody except you. There is a good chance you are using it wrong.

What information do you need to figure it out?

Dunno, let me think… how about a runnable example that displays the behaviour you see?