48         try {
  49             byte[] bytes = Files.readAllBytes(cf);
  50             return MethodHandles.lookup().defineHiddenClass(bytes, true).lookupClass();
  51         } catch (IOException e) {
  52             throw new UncheckedIOException(e);
  53         } catch (IllegalAccessException e) {
  54             throw new RuntimeException(e);
  55         }
  56     }
  57 
  58     /*
  59      * Test Field::set that can write the value of a non-static final field
  60      * in a normal class
  61      */
  62     @Test
  63     public void testFieldsInNormalClass() throws Throwable {
  64         // despite the name "HiddenClass", this class is loaded by the
  65         // class loader as non-hidden class
  66         Class<?> c = Fields.class;
  67         Fields o = new Fields();
  68         assertFalse(c.isHiddenClass());
  69         readOnlyAccessibleObject(c, "STATIC_FINAL", null, true);
  70         readWriteAccessibleObject(c, "STATIC_NON_FINAL", null, false);
  71         readWriteAccessibleObject(c, "FINAL", o, true);
  72         readWriteAccessibleObject(c, "NON_FINAL", o, false);
  73     }
  74 
  75     /*
  76      * Test Field::set that fails to write the value of a non-static final field
  77      * in a hidden class
  78      */
  79     @Test
  80     public void testFieldsInHiddenClass() throws Throwable {
  81         assertTrue(hiddenClass.isHiddenClass());
  82         Object o = hiddenClass.newInstance();
  83         readOnlyAccessibleObject(hiddenClass, "STATIC_FINAL", null, true);
  84         readWriteAccessibleObject(hiddenClass, "STATIC_NON_FINAL", null, false);
  85         readOnlyAccessibleObject(hiddenClass, "FINAL", o, true);
  86         readWriteAccessibleObject(hiddenClass, "NON_FINAL", o, false);
  87     }
  88 
  89     private static void readOnlyAccessibleObject(Class<?> c, String name, Object o, boolean isFinal) throws Exception {
  90         Field f = c.getDeclaredField(name);
  91         int modifier = f.getModifiers();
  92         if (isFinal) {
  93             assertTrue(Modifier.isFinal(modifier));
  94         } else {
  95             assertFalse(Modifier.isFinal(modifier));
  96         }
  97         assertTrue(f.trySetAccessible());
  98         assertTrue(f.get(o) != null);
  99         try {
 100             f.set(o, null);
 101             assertTrue(false, "should fail to set " + name);

  48         try {
  49             byte[] bytes = Files.readAllBytes(cf);
  50             return MethodHandles.lookup().defineHiddenClass(bytes, true).lookupClass();
  51         } catch (IOException e) {
  52             throw new UncheckedIOException(e);
  53         } catch (IllegalAccessException e) {
  54             throw new RuntimeException(e);
  55         }
  56     }
  57 
  58     /*
  59      * Test Field::set that can write the value of a non-static final field
  60      * in a normal class
  61      */
  62     @Test
  63     public void testFieldsInNormalClass() throws Throwable {
  64         // despite the name "HiddenClass", this class is loaded by the
  65         // class loader as non-hidden class
  66         Class<?> c = Fields.class;
  67         Fields o = new Fields();
  68         assertFalse(c.isHidden());
  69         readOnlyAccessibleObject(c, "STATIC_FINAL", null, true);
  70         readWriteAccessibleObject(c, "STATIC_NON_FINAL", null, false);
  71         readWriteAccessibleObject(c, "FINAL", o, true);
  72         readWriteAccessibleObject(c, "NON_FINAL", o, false);
  73     }
  74 
  75     /*
  76      * Test Field::set that fails to write the value of a non-static final field
  77      * in a hidden class
  78      */
  79     @Test
  80     public void testFieldsInHiddenClass() throws Throwable {
  81         assertTrue(hiddenClass.isHidden());
  82         Object o = hiddenClass.newInstance();
  83         readOnlyAccessibleObject(hiddenClass, "STATIC_FINAL", null, true);
  84         readWriteAccessibleObject(hiddenClass, "STATIC_NON_FINAL", null, false);
  85         readOnlyAccessibleObject(hiddenClass, "FINAL", o, true);
  86         readWriteAccessibleObject(hiddenClass, "NON_FINAL", o, false);
  87     }
  88 
  89     private static void readOnlyAccessibleObject(Class<?> c, String name, Object o, boolean isFinal) throws Exception {
  90         Field f = c.getDeclaredField(name);
  91         int modifier = f.getModifiers();
  92         if (isFinal) {
  93             assertTrue(Modifier.isFinal(modifier));
  94         } else {
  95             assertFalse(Modifier.isFinal(modifier));
  96         }
  97         assertTrue(f.trySetAccessible());
  98         assertTrue(f.get(o) != null);
  99         try {
 100             f.set(o, null);
 101             assertTrue(false, "should fail to set " + name);