I am using the Authenticator class in Java for proxy authentication in my application. The authentication works correctly when I enter the wrong credentials initially, as it throws an error. However, once I enter the correct credentials, subsequent attempts with incorrect credentials still succeed. It seems like the correct credentials are being cached and reused even when I want to authenticate with new credentials.

I’m doing some work about using proxy server to visit websites.I learnt about these two different proxy servers but I wanna know more about the differences between these two proxy.Here are the questions.
1.I know that tunnel proxies have one more central node than direct proxies to send request.And I searched that it’s safer than direct proxy, but I don’t know how safe it is? And what technology makes it safer？
2.The business I am currently doing requires high time consumption.(response time need to be in 1 second) The tunnel proxy I used could hardly meet my needs. And I wonder it’s the quality of the proxy server or because of the central node that costs time?