You can have a 32-bit Processing / Java stack on your 64-bit Windows.
See https://forum.processing.org/topic/32-bit-or-64-bit-processing
If you really need lot of memory, I believe latest beta of Processing has a 64-bit version of the Serial library, but I don't know if it works well.
See https://forum.processing.org/topic/32-bit-or-64-bit-processing
If you really need lot of memory, I believe latest beta of Processing has a 64-bit version of the Serial library, but I don't know if it works well.