The language will not allow any array to have a size greater than Integer.MAX_VALUE (2^31 - 1, about 2 billion). However, stricter limits will probably be imposed by the amount of memory on your machine, the OS's rules about how programs can allocate memory, and the startup parameters for heap size given to the VM.
In most cases, you should be able to handle 50-70 MB, provided you gave a big enough -Xmx argument to the VM at startup.
However, you do NOT need to (and should not) load the whole file into memory at once to copy or move it. EIther use File.rename, or read and write smaller pieces (a few k or tens of k) at a time.