Best practice for storing large amounts of data with J2ME

Question

I am developing a J2ME application that has a large amount of data to store on the device (in the region of 1MB but variable). I can't rely on the file system so I'm stuck the Record Management System (RMS), which allows multiple record stores but each have a limited size. My initial target platform, Blackberry, limits each to 64KB.

I'm wondering if anyone else has had to tackle the problem of storing a large amount of data in the RMS and how they managed it? I'm thinking of having to calculate record sizes and split one data set accross multiple stores if its too large, but that adds a lot of complexity to keep it intact.

There is lots of different types of data being stored but only one set in particular will exceed the 64KB limit.

Answer 1

For anything past a few kilobytes you need to use either JSR 75 or a remote server. RMS records are extremely limited in size and speed, even in some higher end handsets. If you need to juggle 1MB of data in J2ME the only reliable, portable way is to store it on the network. The HttpConnection class and the GET and POST methods are always supported.

On the handsets that support JSR 75 FileConnection it may be valid alternative but without code signing it is an user experience nightmare. Almost every single API call will invoke a security prompt with no blanket permission choice. Companies that deploy apps with JSR 75 usually need half a dozen binaries for every port just to cover a small part of the possible certificates. And this is just for the manufacturer certificates; some handsets only have carrier-locked certificates.