Java 11 模块信息和注释处理器

Question

How can we provide an annotation processor with a Java 11 module?

To register the annotation provider we need the following module-info entry:

import javax.annotation.processing.Processor;
import com.mycompany.mylib.impl.MyAnnotationProcessor;

module com.mycompany.mylib {

    provides Processor with MyAnnotationProcessor;

}

Now, unfortunately, this is not enough since the packages javax.annotation.processing , javax.lang.model.* and javax.tools are not in the java.base module but in the java.compiler module.

With Java SE 8 everything was just available in the JRE, but with Java 11 we get the option to use only a subset. With jlink we then can create smaller runtime images.

Now, of course, I could just add the following to the module-info:

requires java.compiler;

But this would cause java.compiler to be part of the custom runtime image as well.

But annotation processing is something special: it is code run at compile time, not at runtime. Thus it should not be part of the runtime image. It should only be a compile-time requirement/ dependency.

Is there a way to solve this with the Java 11 module system?

Answer 1

It seems that you should write

requires static java.compiler;

It's stated in the JLS 7.7.1 that

The requires keyword may be followed by the modifier static . This specifies that the dependence, while mandatory at compile time, is optional at run time.