Can't call methods of private subclasses with java_method in java 12

[yamam]

Environment

jruby 9.2.8.0 (2.5.3) 2019-08-12 a1ac7ff OpenJDK 64-Bit Server VM 12.0.2+10 on 12.0.2+10 +jit [mswin32-x86_64]

JavaTest.java

public class JavaTest {

    public interface PublicInterface {
        public void publicMethod(Integer a);
        public void publicMethod(Long a);
    }

    public PublicInterface publicMember = new PrivateSubclass();

    private class PrivateSubclass implements PublicInterface {
        public void publicMethod(Integer a) {System.out.println("publicMethod(Integer)");}
        public void publicMethod(Long a) {System.out.println("publicMethod(Long)");}
    }
}

test.rb

java_import 'JavaTest'
JavaTest.new.publicMember.java_method(:publicMethod, [java.lang.Integer.java_class]).call(1)

Expected Behavior

You can call methods of private subclasses with java_method in java 8.

$ javac JavaTest.java
$ jruby test.rb
publicMethod(Integer)

Actual Behavior

You can't call methods of private subclasses with java_method in java 12.

$ jruby test.rb
2019-08-20T09:36:29.010+09:00 [main] WARN FilenoUtil : Native subprocess control requires open access to sun.nio.ch
Pass '--add-opens java.base/sun.nio.ch=org.jruby.dist' or '=org.jruby.core' to enable.
TypeError: illegal access on 'publicMethod': class org.jruby.javasupport.JavaMethod (in module org.jruby.dist) cannot access a member of class JavaTest$PrivateSubclass with modifiers "public"
    call at org/jruby/RubyMethod.java:120
  <main> at test.rb:2

[headius]

Looks like this is a problem with how we determine whether we should set methods accessible.

The logic here basically turns off setAccessible when on Java 9 or higher:

jruby/core/src/main/java/org/jruby/util/cli/Options.java

Line 319 in cf7a2bf

private static boolean calculateSetAccessibleDefault() {

I'm going to look at changing this property back to always true and modify the logic that uses it to use our trySetAccessible logic.

[headius]

It looks like all places that use the JI_SETACCESSIBLE option (with the default "false" on Java 9+) are already using our safe trySetAccessible that's aware of modules. Changing this calculated default to "true" appears to work fine.

I'm going to push it to a PR to make sure it doesn't affect too much other code.