/usr/bin/jh_classpath is in javahelper 0.63ubuntu1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 | #!/bin/bash --
set -e
. /usr/share/javahelper/jh_lib.sh
syntax()
{
   echo -e "Usage: jh_classpath [options] [jar(s)]"
   echo -e "Options:"
   echo -e "\t-h --help: show this text"
   echo -e "\t-V --version: show the version"
   echo -e "\t-i --indep: act on all Arch: all packages"
   echo -e "\t-a --arch: act on all Arch-specific packages"
   echo -e "\t-s --same-arch: alias of --arch for compatibility with debhelper"
   echo -e "\t-p<package> --package=<package>: package to act on (default=all)"
   echo -e "\t-P<packagedir> --tmpdir=<package>: package directory (default=\$CWD/debian/package)"
   echo -e "\t-c<classpath> --classpath=<classpath>: The classpath to set on the jar(s)"
   echo -e "\t-v --verbose: show more information while running"
   echo -e "\t-n --no-act: don't actually do anything, just print the results"
   exit 1
}
ARGS="i indep a arch s same-arch p package P tmpdir v verbose n no-act c classpath" parseargs "$@"
dh_testdir
VERBOSE="`getarg v verbose`"
NOACT="`getarg n noact`"
if [ "$ARGC" == "0" ]; then
	# read debian/$package.classpath
	for p in `findpackages`; do
		if [ -f "debian/$p.classpath" ]; then
			cat "debian/$p.classpath" | while read jar cpath; do
				if [ ! -f "$jar" ] ; then
                                    jar="debian/$p/$jar"
                                fi
				if [ -n "$VERBOSE" ]; then
					echo "Setting classpath on $jar to $cpath"
				fi
				if [ -n "$NOACT" ]; then
					echo "Would run jh_manifest -p$p --classpath=$cpath $jar"
				else
					jh_manifest "-p$p" "--classpath=$cpath" "$jar"
				fi
			done
		elif [ -f "debian/classpath" ]; then
			cat "debian/classpath" | while read jar cpath; do
				if [ ! -f "$jar" ] ; then
                                    jar="debian/$p/$jar"
                                fi
				if [ -n "$VERBOSE" ]; then
					echo "Setting classpath on $jar to $cpath"
				fi
				if [ -n "$NOACT" ]; then
					echo "Would run jh_manifest -p$p --classpath=$cpath $jar"
				else
					jh_manifest "-p$p" "--classpath=$cpath" "$jar"
				fi
			done
		fi
	done
else
	# process jars with -c or $CLASSPATH
	for (( i=0 ; i<ARGC; i++ )); do
		jar=${ARGV[i]}
                p=$(firstpackage)
		if [ -f "$jar" ]; then
			cpath="`getarg c classpath`"
			if [ ! -f "$jar" ] ; then
				jar="debian/$p/$jar"
                        fi
			if [ -z "$cpath" ]; then
				cpath="`sed 's/:/ /g' <<< $CLASSPATH`"
			fi
			if [ -z "$cpath" ]; then
				echo "Could not find a classpath, doing nothing"
				exit 0
			fi
			if [ -n "$VERBOSE" ]; then
				echo "Setting classpath on $jar to $cpath"
			fi
			if [ -n "$NOACT" ]; then
				echo "Would run jh_manifest -p$p --classpath=$cpath $jar"
			else
				jh_manifest "-p$p" "--classpath=$cpath" "$jar"
			fi
		else
			echo "Cannot find $jar: skipping"
		fi
	done
fi
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