We have an application that is running into a problem with a utility program.
Below is a standalone reproducer.
The program does not import the SPI package sun.nio.ch - it isn't aware of
it, and SocketChannel.isConnected() is a public method of a public type. In
short, it does not break any law of encapsulation, so call
setAccessible(true) should be OK.
import java.lang.reflect.Method;
public class JDK9Nio {
public static void main(String args[]) throws Exception {
call();
}
public static void call() throws Exception {
Class clzz = Class.forName("java.nio.channels.SocketChannel");
Method open = clzz.getMethod("open");
Object obj = open.invoke(null);
Method isConn = obj.getClass().getMethod("isConnected");
isConn.setAccessible(true); // OK with JDK8, fail with JDK9
System.out.println(isConn.invoke(obj));
}
}
java JDK9Nio
Exception in thread "main" java.lang.reflect.InaccessibleObjectException:
Unable to make member of class sun.nio.ch.SocketChannelImpl accessible: module
java.base does not export sun.nio.ch to unnamed module @3857f613
at
jdk.internal.reflect.Reflection.throwInaccessibleObjectException(java.base@9-ea/Reflection.java:414)
at
java.lang.reflect.AccessibleObject.checkCanSetAccessible(java.base@9-ea/AccessibleObject.java:174)
at
java.lang.reflect.Method.checkCanSetAccessible(java.base@9-ea/Method.java:192)
at
java.lang.reflect.Method.setAccessible(java.base@9-ea/Method.java:186)
at JDK9Nio.call(JDK9Nio.java:14)
at JDK9Nio.main(JDK9Nio.java:6)
It's easy to say that the program should be re-written and the setAccessible is
not necessary but this is a utility program over which the application has no
control (a jython script).
What's ugly is that the internal implementation is showing through to the
application.
Many people especially tool makers have this problem:
https://bugs.eclipse.org/bugs/show_bug.cgi?id=482318
https://netbeans.org/bugzilla/show_bug.cgi?id=258952
https://netbeans.org/bugzilla/show_bug.cgi?id=262765
http://mail.openjdk.java.net/pipermail/quality-discuss/2015-November/000468.html
https://community.oracle.com/thread/3937249
