AtomicIntegerFieldUpdater访问权限问题

AtomicIntegerFieldUpdater所要修改的变量必须可在当前类访问，否则将抛出异常

java.lang.RuntimeException: java.lang.IllegalAccessException: Class XXXXX can not access a member of class XXX with modifiers "private volatile"

原因在AtomicIntegerFieldUpdaterImpl构造函数之中

final Field field;
final int modifiers;
try {
	field = AccessController.doPrivileged(
		new PrivilegedExceptionAction<Field>() {
			public Field run() throws NoSuchFieldException {
				return tclass.getDeclaredField(fieldName);
			}
		});
	modifiers = field.getModifiers();
	sun.reflect.misc.ReflectUtil.ensureMemberAccess(
		caller, tclass, null, modifiers);
	ClassLoader cl = tclass.getClassLoader();
	ClassLoader ccl = caller.getClassLoader();
	if ((ccl != null) && (ccl != cl) &&
		((cl == null) || !isAncestor(cl, ccl))) {
		sun.reflect.misc.ReflectUtil.checkPackageAccess(tclass);
	}
} catch (PrivilegedActionException pae) {
	throw new RuntimeException(pae.getException());
} catch (Exception ex) {
	throw new RuntimeException(ex);
}

代码中的第10行直接获取Modifiers，并没有抑制JVM的访问权限检查

将成员变量修饰符换掉即可