The supported encryption algorithms for Sun Java are listed in the Sun Providers Documention
, including the supported key lengths. If you don't want to use standard algorithms like 3DES or AES with restricted key sizes, you could choose Blowfish or RC4.
Bear in mind that RC4 is remarkably easy to use insecurely, as in the WEP protocol. In addition, RC2 was designed
so that the NSA could break it 20 years ago if it used 40 bit keys, and any algorithm using keys shorter than 128 bits is going to be fairly vulnerable today.