I'd like to know how to use too much data with a disk to load into Java memory.

Create a swap partition.

And hold Xmx big among jvm options.

If you run out of physical memory, you will automatically use swap partitions, but performance will be slower than you can imagine.

The swapping process is a repetition of the process of transferring data from memory to disk and then uploading it back to memory if necessary, so it is inevitably slow.

The recommended method is to divide the data into chunk sizes and load as much as you need.