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copied!<p>This will do what you are trying to do while providing type safety. There's no way to avoid an unchecked warning, but the type checking done here justifies its suppression.</p> <pre><code> public static void main(String[] args) throws Exception { Class<? extends Creator<String>> clz = load(argv[0], String.class); Constructor<? extends Creator<String>> ctor = clz.getConstructor(); Creator<String> creator = ctor.newInstance(); System.out.println(creator.create()); } public static <T> Class<? extends Creator<T>> load(String fqcn, Class<T> type) throws ClassNotFoundException { Class<?> any = Class.forName(fqcn); for (Class<?> clz = any; clz != null; clz = clz.getSuperclass()) { for (Object ifc : clz.getGenericInterfaces()) { if (ifc instanceof ParameterizedType) { ParameterizedType pType = (ParameterizedType) ifc; if (Creator.class.equals(pType.getRawType())) { if (!pType.getActualTypeArguments()[0].equals(type)) throw new ClassCastException("Class implements " + pType); /* We've done the necessary checks to show that this is safe. */ @SuppressWarnings("unchecked") Class<? extends Creator<T>> creator = (Class<? extends Creator<T>>) any; return creator; } } } } throw new ClassCastException(fqcn + " does not implement Creator<String>"); } </code></pre> <p>The main restriction you have to adhere to is that a class in the hierarchy must specify the type parameter. For example <code>class MyCreator implements Creator<String></code>. You can't use it with <code>class GenericCreator<T> implements Creator<T></code>. </p> <p>It doesn't currently handle the valid case where you create a new interface <code>interface StringCreatorIfc extends Creator<String></code>, and have a class implement that. It could be enhanced to do that, but I'll leave that as an exercise for those inclined.</p>

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