Replacement for JDK8 APIs

[Stéphane Nicoll]

Hi,

I am working on the Spring Boot project[1] and I am trying to make sure our
codebase compiles with the current JDK9 build[2]. So far I've hit two major
issues:

We use "sun.misc.VMSupport" to retrieve the port being used by the Java
remote debugging. You can find the actual code in RemoteDebugPortProvider[3]

We have an annotation processor that inspects all classes annotated with
@ConfigurationProperties and generates some meta-data about them. One
important piece of this is to extract the default value assigned to fields.
Consider the following example

@ConfigurationProperties
public class Foo {

  private static final String DEFAULT_NAME = "name";

  private String name = DEFAULT_NAME;

  private Integer counter = 42;

  private List<String> hosts = Collections.singletonList("localhost");


}

What we've build is a visitor that navigates to those elements and extracts
the default values assigned to each field, including navigating to parent
element (the "name" constant there) or inferring value from method
parameters ("localhost"). The  current code relies on a feature of the JDK
that is no longer exported[4]:


java.lang.IllegalAccessException: class
org.springframework.boot.configurationprocessor.fieldvalues.javac.Trees
cannot access class com.sun.tools.javac.api.JavacTrees (in module
jdk.compiler) because module jdk.compiler does not export
com.sun.tools.javac.api to unnamed module @5a7fe64
<https://github.com/spring-projects/spring-boot/commit/5a7fe64f>

Does anybody has some insight as how we could migrate those two use cases?
In particular, the second use case could be implemented with a contract of
javax.lang.model but we haven't found how to do it.

Thank you,
S.



[1] https://github.com/spring-projects/spring-boot
[2] https://github.com/spring-projects/spring-boot/issues/7226
[3]
https://github.com/spring-projects/spring-boot/blob/master/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/tunnel/server/RemoteDebugPortProvider.java
[4]
https://github.com/spring-projects/spring-boot/blob/master/spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/fieldvalues/javac/Trees.java