Internally we've implemented the package private method java.lang.StringCoding.countPositives for efficiently counting positive bytes in a byte array. This has been developed and deployed to support the needs of built-in charset encoders/decoders, where counting positives is a quick ASCII test. It appears there's utility for such a method elsewhere - not the least in non-builtin decoders and encoders - so we should consider exposing this as a public API.

Suggestion to add a public method to java.util.Arrays, delegating when appropriate to the internal method in java.lang.StringCoding