Reading an InputStream twice in Java

[Jonah]

What is the best way of reading in an InputStream twice in Java? I'm
using the mark(int bytes) and reset() method, but it's flawed as it
limits the number of bytes that can be read before the reset() becomes
invalid.

[Gordon V. Cormack]

Don't read it twice. Save the result in a data structure.

[Jonah]

Would a String be sufficient? Then create a Scanner using the String
to "re-read" in the MIPS assembly language? Or would it be better to
use an ArrayList or Hashtable?

[Gordon V. Cormack]

A string scanner would work, but beware string concatenation in
building the string. x + y takes time proportional to the length
of x.

It is probably better to use ArrayList as you suggest.