[java-atk-wrapper: 1/2] Check against getAccessibleStateSet returning null

[Samuel Thibault <sthibaul src gnome org>]

commit 9a4eb697e1c2027724d5b62b510b0644f99099a6
Author: Samuel Thibault <samuel thibault ens-lyon org>
Date:   Mon Apr 1 23:22:59 2019 +0200

    Check against getAccessibleStateSet returning null
    
    Fixes https://bugzilla.gnome.org/show_bug.cgi?id=775609

 jni/src/jawobject.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/jni/src/jawobject.c b/jni/src/jawobject.c
index bef6fe3..e14c20c 100644
--- a/jni/src/jawobject.c
+++ b/jni/src/jawobject.c
@@ -486,6 +486,8 @@ jaw_object_ref_state_set (AtkObject *atk_obj)
                                           "getAccessibleStateSet",
                                           "()Ljavax/accessibility/AccessibleStateSet;" );
   jobject jstate_set = (*jniEnv)->CallObjectMethod( jniEnv, ac, jmid );
+  if (jstate_set == NULL)
+    return NULL;
 
   jclass classAccessibleStateSet = (*jniEnv)->FindClass(jniEnv,
                                                         "javax/accessibility/AccessibleStateSet" );