I have a lab for Java Programming that involves infix expressions from a file and coverts the infix to postfix notation. There's an additional part involved with converting the converted infix expression back into original infix, so if it was 8 4 + it would go back to 8 + 4 and another with converting the postfix equation to prefix. I already have the infix to postfix part, but I need help on postfix to infix and postfix to prefix. The specifications for the lab also imply that there must be no additional files, so postfix to prefix has to come from the converted solution.

Even so, getting assistance on java programming for postfix to prefix or postfix back to infix would be greatly appreciated!