TameAThrottledAPI.java

MyStubbornAPIInterface actualInstance = ... // Create it however you'd create your original instance.
MyStubbornAPIInterface proxiedInstance = (MyStubbornAPIInterface) Proxy.newProxyInstance(actualInstance.getClass().getClassLoader(),
        new Class[]{MyStubbornAPIInterface.class}, (proxy, method, args) -> {
            while (true) {
                try {
                    return method.invoke(actualInstance, args);
                } catch (MyThrottlingException e) {
                    try {
                        Thread.sleep(ThreadLocalRandom.current().nextInt(1, 5) * 1000L);
                    } catch (InterruptedException e) {
                        Thread.currentThread().interrupt();
                    }
                }
            }
        });