How come my classpath isn't being used?

Question

I have projects/plugin/target/mypackage.jar

Then I have projects/runner/Runner.java

When I run jar tf mypackage.jar, it doesn't have some classes it relies upon. Runner.java wants to import mypackage.MyClass

When I do javac -cp '.:../plugin/target/*' Runner.java from the runner folder, it complains that some dependencies of MyClass aren't available.

My runner folder contains the appropriate JAR files. If I copy-paste those JAR files into target folder, the compilation works. Considering I'm using . in my classpath, why wouldn't the package know where to find the correct JARs?

Java JAR files always ignore the command line class path setting. Use the MANIFEST.MFfile to set the class path for a JAR file. — markspace, Aug 25 '17 at 16:25
Thanks Mark, let me look into both. If this is dupe, I will close. — Dave Stein, Aug 25 '17 at 16:28
Err why would it be that when I do `javac -help` or `java -help` it doesn't show `jar` as an option. `javac: invalid flag: -jar` — Dave Stein, Aug 25 '17 at 16:37

score 0 · Accepted Answer · answered Aug 25 '17 at 19:47

0

After some advice and shenanigans I found that this works:

javac -cp './*:../plugin/target/*' Runner.java.

The key difference being ./* rather than .

If anyone can better explain why that is the case, I will gladly mark them as the answer.

answered Aug 25 '17 at 19:47

Dave Stein

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Can't answer due to hold but [a _directory_ in the classpath is only used to find class files](http://docs.oracle.com/javase/8/docs/technotes/tools/unix/classpath.html#A1100592) while a jarfile name _or_ [a wildcard (NOT in manifest) is used to find jarfiles](http://docs.oracle.com/javase/8/docs/technotes/tools/unix/classpath.html#A1100762). Thus `.` finds classes but `./*` or `../plugin/target/*` finds jars, and your Q only mentioned wanting to find jars – dave_thompson_085 Aug 26 '17 at 00:05

How come my classpath isn't being used?

1 Answers1