Use condy directly such that a ConstantsRegistry class isn't generate…

…d as a side effect.

src/main/java/org/cojen/tupl/core/DirectPageOpsSelector.java

@@ -52,16 +52,14 @@ static String kindStr() {
         }
     }
 
-    static final Throwable failure;
+    static volatile Object result;
 
     static {
-        Throwable ex = null;
         try {
             select();
         } catch (Throwable e) {
-            ex = e;
+            result = e;
         }
-        failure = ex;
     }
 
     private static void select() throws Throwable {
@@ -128,14 +126,18 @@ private static void select() throws Throwable {
             return;
         }
 
+        result = unsafe;
+
         ClassMaker cm = ClassMaker.beginExplicit
             ("org.cojen.tupl.core.DirectPageOps", MethodHandles.lookup());
 
         cm.addField(unsafe.getClass(), "U").private_().static_().final_();
         cm.addField(long.class, "O").private_().static_().final_();
 
         MethodMaker mm = cm.addClinit();
-        mm.field("U").setExact(unsafe);
+        var unsafeVar = mm.var(DirectPageOpsSelector.class)
+            .condy("U").invoke(Object.class, "U").cast(unsafe.getClass());
+        mm.field("U").set(unsafeVar);
         mm.field("O").set(mm.field("U").invoke("arrayBaseOffset", byte[].class));
 
         mm = cm.addMethod(int.class, "kind").static_();
@@ -223,4 +225,11 @@ private static Throwable combine(Throwable existing, Throwable additional) {
         existing.addSuppressed(additional);
         return existing;
     }
+
+    // Condy method which is called by the generated code.
+    static Object U(MethodHandles.Lookup caller, String name, Class type) {
+        Object unsafe = result;
+        result = null;
+        return unsafe;
+    }
 }