This implements a bash function (GNU Bash or Bourne-again shell) that compiles and runs a target java class (with attendant .java file). It assumes your target exists somewhere in $GITHUB_PATH

compileRun.sh

#!/bin/bash
readonly GITHUB_PATH=~/Documents/GitHub

function compileRun () {
    r () {
        if [ $1 -eq 0 ]
            then #compiled successfully
                java $2
                return 0
            else #compile failed
                echo "\e[31mCouldn't compile, so we will not run \"java $2\"\e[0m" >&2 # TODO: this does not correctly set the terminal colour
                return 1
        fi
    }
    #TODO: from lines 15 to 18, this does not work
    if [[${1} =~ ^[\S\s]+?\.java$]]; then #user included the .java extension in the target file name
        set -- $(echo ${1} | sed -e 's/^([\S\s]+?)\.java/\1/g') "${@:2}"
    # end TODO
    if test -f "${1}.java"; then #this means that it finds the file you're trying to compile in the present directory
        javac "${1}.java"
        r $? $1
        return $?
    else #couldn't find your file, so it needs to search
        a=$(find ${GITHUB_PATH} -name ${1}.java)
        b=$(echo $a | sed -e 's/[^\/]*$//g')
        cd "$b"
        javac "$a"
        r $? $1
        return $?
    fi

}