Java Reeds were developed by Vandoren in 1983 for Jazz and Commercial music.

A thicker and more flexible pallet* than the traditional reed allows vibration over a larger surface area with maximum elasticity. This type of vertebral column gives the musician much greater playing flexibility as the resultant elasticity zone is very large.

The JA stands for Jazz, and the VA for Variety (entertainment music) and, of course, Vandoren!
*The pallet zone is where the sound waves are propogated with the greatest range. From the tip, the waves are absorbed further in the Java Reed.