Jasmin is an assembler for Java bytecodes. However, I don't know if it can handle the exit from javap.
UPDATE
The Jasmin documentation says this javapoutput:
Sun provides a javap program that can print assembly code in a class file. However, javap output is not suitable for use as an assembler format. It is intended for human reading, and not for analysis by assembler, so it has a number of omissions and shortcomings.
, , , javap .