The `java.net.ProxySelector` methods `select` and `connectFailure` now throw `IllegalArgumentException` in all `ProxySelector` implementations when called with invalid parameters.

Previously, the `select` method of the `ProxySelector` returned by `ProxySelector.of(InetSocketAddress)` was incorrectly throwing a `NullPointerException` when its `uri` parameter was `null` or if the protocol could not be determined. The `connectFailed` method of the same `ProxySelector` instance returned without checking its parameters for validity.