Merge pull request #192 from jnr/better_module_handling

Use tricks to improve module visibility issues

src/main/java/jnr/posix/JavaLibCHelper.java

@@ -78,6 +78,27 @@ private static class ReflectiveAccess {
  private static final Field FILE_DESCRIPTOR_HANDLE;
 
  static {
+ try {
+ Method getModule = Class.class.getMethod("getModule");
+ Class<?> Module = Class.forName("java.lang.Module");
+ Method isOpen = Module.getMethod("isOpen", String.class, Module);
+ Method isNamed = Module.getMethod("isNamed");
+ Method addOpens = Module.getMethod("addOpens", String.class, Module);
+ Object JNRPosixModule = getModule.invoke(ReflectiveAccess.class);
+ Object JavaBaseModule = getModule.invoke(FileDescriptor.class);
+
+ if (!((Boolean) isOpen.invoke(JavaBaseModule, "java.io", JNRPosixModule))) {
+ // warn that many APIs will be broken without module access
+ System.err.println("Some JDK modules may not be open to jnr-posix, which will break file descriptor and process APIs. See https://github.com/jnr/jnr-posix/wiki/Using-POSIX-with-Java-Modules");
+ } else if (!((Boolean) isNamed.invoke(JNRPosixModule))) {
+ // explicitly open them to avoid the implicitly open warning
+ addOpens.invoke(JavaBaseModule, "java.io", JNRPosixModule);
+ addOpens.invoke(JavaBaseModule, "sun.nio.ch", JNRPosixModule);
+ }
+ } catch (Exception e) {
+ // ignore, we're not on Java 9+
+ }
+
  Method getFD;
  Class selChImpl;
  try {