How can I fix a JAVAC Invalid flag error?

Question

I'm trying to compile a shell script with javac and it keeps returning me this error:

$ bash run_RGE.sh

javac: invalid flag: Element.java
Usage: javac <options> <source files>
use -help for a list of possible options
javac: invalid flag: RGE.java
Usage: javac <options> <source files>
use -help for a list of possible options
javac: invalid flag: -Xms1024m
Usage: javac <options> <source files>
use -help for a list of possible options
sleep: missing operand
Try "sleep --help" for more information.

My shell script looks like this :

#!/bin/bash
# -*- coding: utf-8 -*-
export LIB=C:/home/b04280/Transfert/Libs/
CLASSPATH=$(echo "$LIB"/*.jar | tr ' ' ':')
export ficIn=C:/home/b04280/Transfert/rgeII.xlsx/
export repIn=C:/home/b04280/Transfert/rgeII/
export repOut=C:/home/b04280/Transfert/rgeIIcible/
javac -cp $CLASSPATH Element.java
javac -cp $CLASSPATH RGE.java
javac -Xms1024m -Xmx1024m -cp $CLASSPATH  RGE $ficIn $repIn $repOut > docx.txt
sleep

I am wondering where this error comes from, I looked at other questions on here regarding the same topic but their solutions didn't seem fit to my particular case.

Any help please? Thanks in advance.

PS. I also have the sleep error (I "translated" this script from batch --> shell and "sleep" was the replacement I found for "pause")

Use bash -x run_RGE.sh, it will show the expanded commands it's running. — Aaron
What are you running your bash script on by the way? If it's git bash or cygwin that might work, but on a real Unix OS the echo "$LIB"/*.jar part won't work with a windows path — Aaron
Thanks for the suggestions; I'm running it on an Linux Virtual Machine. Specifically Mobaxterm. — rifraf_01
not familiar with the tool, but a quick glance at its doc makes me think it doesn't translate windows paths to unix paths like Cygwin and git bash do. That would mean "C:/home/b04280/Transfert/Libs/" isn't a directory from the point of view of your script — Aaron
Also, each entry in the CLASSPATH contains a colon, but the CLASSPATH is colon-separated. — glenn jackman

Aaron Aaron · Accepted Answer · 2020-10-02T20:52:59

I believe this should be closer to what you need :

#!/bin/bash
# -*- coding: utf-8 -*-
lib=/home/b04280/Transfert/Libs
classpath=$(echo "$lib"/*.jar | tr ' ' ':')
fic_in=/home/b04280/Transfert/rgeII.xlsx/
rep_in=/home/b04280/Transfert/rgeII/
rep_out=/home/b04280/Transfert/rgeIIcible/
javac -cp "$classpath" Element.java
javac -cp "$classpath" RGE.java
java -Xms1024m -Xmx1024m -cp "$classpath" RGE "$fic_in" "$rep_in" "$rep_out" > docx.txt

In particular :

unix paths
quoted variables to avoid them being parsed as multiple arguments if their values contain spaces
in the last command RGE is a class name rather than a file path, you specify memory settings, plus the command produces useful output ; it seems to me it should execute the code (java) rather than compile it (javac)
I'm not sure it's necessary, but removing the trailing slash from $LIB's value avoids having double slashes in $CLASSPATH which might confuse java[c]
removed the useless exports (they'd be useful if you invoked other bash scripts or binaries that would rely on those variables being set, but you're just passing them as parameters)
applied naming conventions (avoid uppercase variables as they might conflict with environment variables, use snake_case rather than camelCase).

I'm not sure in your context whether you're executing the linux version of the java[c] binaries or the windows one. If it's the windows one you'll need to replace the tr ' ' ':' part by tr ' ' ';' as the classpath on windows is semi-colon separated rather than colon-separated.

How can I fix a JAVAC Invalid flag error?

1 Answers