These tests fail repeatably on Ubuntu 16.04 LTS
 java/awt/Modal/FileDialog/FileDialogNonModal2Test.java
java/awt/Modal/FileDialog/FileDialogNonModal6Test.java
java/awt/Modal/FileDialog/FileDialogNonModal7Test.java
Test 6 + 7 will fail even if they are the only test that is run.
Test2 passes "standalone" but will fail if run after Test1 (not listed here).

Test2:
----------System.err:(5/351)----------
Gtk-Message: GtkDialog mapped without a transient parent. This is discouraged.
[xcb] Unknown sequence number while processing queue
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
java: ../../src/xcb_io.c:274: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed.
----------rerun:(23/1981)*----------

Test 6:
----------System.out:(0/0)----------
----------System.err:(5/351)----------
Gtk-Message: GtkDialog mapped without a transient parent. This is discouraged.
[xcb] Unknown request in queue while dequeuing
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
java: ../../src/xcb_io.c:179: dequeue_pending_request: Assertion `!xcb_xlib_unknown_req_in_deq' failed.
----------rerun:(23/1981)*----------

Test7:

----------System.out:(0/0)----------
----------System.err:(5/351)----------
Gtk-Message: GtkDialog mapped without a transient parent. This is discouraged.
[xcb] Unknown request in queue while dequeuing
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
java: ../../src/xcb_io.c:179: dequeue_pending_request: Assertion `!xcb_xlib_unknown_req_in_deq' failed.

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These are more than test issues and need to be investigated.