org.jboss.weld.tests.unit.util.reflection.FormatsTest fails with JDK 9. This test uses BCEL classes.

The exception (which is caught and hidden in the code) is thrown upon reaching this line:

class org.jboss.weld.util.reflection.Formats cannot access class com.sun.org.apache.bcel.internal.classfile.ClassParser (in module java.xml) because module java.xml does not export com.sun.org.apache.bcel.internal.classfile to unnamed module @345965f2

It seems that in JDK 9 these classes were moved and/or their visibility/accessibility changed.