I suspect you're right. Java doesn't have the best track-record when it comes to SIMD.
Unlike .Net with System.Numerics.Vectors, they're not even interested in making a platform-independent SIMD library for manual optimisation. The JVM holds contempt for such real-world optimisations. I see that Intel have made one though - https://software.intel.com/en-us/articles/vector-api-develop...