Java Programming

Hi, everyone.

I would be very grateful if someone could help me with the two questions I have.

I am working on the program, which has to turn a billion of integers in words, sort them and find a certain character.

My first question is how can I process my convertion of integer other than in loop? ( loop takes about an hour). The algorithm works well for smaller iterations.

Where can I store such large amounts of strings to be able to sort them then and work with them?

Thank you in advance.