Empty entry in PATH env can lead to failure running mvn.cmd, at least on Windows

[scottkurz]

Saw this running Start on a Liberty app on Windows.

ECHO is on.
Liberty Tools running command: \mvn.cmd io.openliberty.tools:liberty-maven-plugin:dev from directory: C:\git\guides\guide-maven-multimodules\finish

with the Terminal immediately ending up in a <Closed> state, without mvn apparently running.

I think what is happening is that when an "empty" entry ends up on the PATH env var, e.g. set PATH="%PATH%;;C:\mydir" then our test (in io.openliberty.tools.eclipse.CommandBuilder to see if mvn.cmd exists in that dir) succeeds

            File tempFile = new File(member + File.separator + executableBaseName);
            if (tempFile.exists()) {

even though there's no mvn there. I think we might want to special case the empty string and not allow this comparison to succeed.

EXCEPT... it would be nice to understand the Windows file/path syntax enough to know what /mvn.cmd is supposed to represent???

Not finding any hits searching so leaving this open.