4.18.2 Piping the output of javac and java

Output from the executables javac and java have their standard output stream and standard error stream piped into Emacs’ batch mode so that error messages like Foo.java:123 point back to the correct file Foo.jtw:123 even if file inclusion (J.T.W. Proof of concept #2 file inclusion) has been used. The programs grep and sed are also used as pipes in the transformation process so they must be present on the client’s system.