rename ReferenceQueue.NULL to NULL_QUEUE

Author: mur47x111

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/heap/ReferenceInternals.java

@@ -161,7 +161,7 @@ public static <T> void setNextDiscovered(Reference<T> instance, Reference<?> new
     }
 
     public static boolean hasQueue(Reference<?> instance) {
-        return cast(instance).queue != Target_java_lang_ref_ReferenceQueue.NULL;
+        return cast(instance).queue != Target_java_lang_ref_ReferenceQueue.NULL_QUEUE;
     }
 
     /*
@@ -229,7 +229,7 @@ public static void processPendingReferences() {
                 } else {
                     @SuppressWarnings("unchecked")
                     Target_java_lang_ref_ReferenceQueue<? super Object> queue = SubstrateUtil.cast(ref.queue, Target_java_lang_ref_ReferenceQueue.class);
-                    if (queue != Target_java_lang_ref_ReferenceQueue.NULL) {
+                    if (queue != Target_java_lang_ref_ReferenceQueue.NULL_QUEUE) {
                         // Enqueues, avoiding the potentially overridden Reference.enqueue().
                         queue.enqueue(ref);
                     }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/heap/Target_java_lang_ref_Reference.java

@@ -119,7 +119,7 @@ public final class Target_java_lang_ref_Reference<T> {
     @Uninterruptible(reason = "The initialization of the fields must be atomic with respect to collection.")
     Target_java_lang_ref_Reference(T referent, Target_java_lang_ref_ReferenceQueue<? super T> queue) {
         this.referent = referent;
-        this.queue = (queue == null) ? Target_java_lang_ref_ReferenceQueue.NULL : queue;
+        this.queue = (queue == null) ? Target_java_lang_ref_ReferenceQueue.NULL_QUEUE : queue;
     }
 
     @KeepOriginal

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/heap/Target_java_lang_ref_ReferenceQueue.java

@@ -33,7 +33,7 @@
 
 @TargetClass(ReferenceQueue.class)
 final class Target_java_lang_ref_ReferenceQueue<T> {
-    @Alias static Target_java_lang_ref_ReferenceQueue<Object> NULL;
+    @Alias static Target_java_lang_ref_ReferenceQueue<Object> NULL_QUEUE;
 
     @Alias @RecomputeFieldValue(kind = RecomputeFieldValue.Kind.Reset) //
     volatile Reference<? extends T> head;