Java Classpath and relative paths

Question

If you have a relative path in the java class path, does this just search the current working directory. Does the same hold for class paths declared in a manifest file. In a manifest file is it relative to the dir the jar is in?

Ex. Cmdline

java -cp somejar.jar

Or

Manifest

Class-Path: somejar.jar

Answer 1

You've actually mentioned two different cases:

Case #1

java -cp foo/bar/somejar.jar ...

In this case the relative path to the JAR (or whatever) is resolved relative to the current directory.

Case #2

java -jar foo/bar/somejar.jar ...

where somejar.jar contains

Class-Path: anotherjar.jar

In this case "foo/bar/somejar.jar" is resolved relative to the current directory (as above), but "anotherjar.jar" is resolved relative to the directory containing "somejar.jar".

(Aside: my understanding is that a Manifest Class-Path: attribute is respected when a JAR file is included via -cp or $CLASSPATH, but it only affects the dependencies of classes loaded from that JAR ... see the "findingclasses" link below.)

References:

• http://docs.oracle.com/javase/7/docs/technotes/tools/windows/classpath.html
• http://docs.oracle.com/javase/7/docs/technotes/tools/findingclasses.html
• http://docs.oracle.com/javase/7/docs/technotes/guides/jar/jar.html
• http://docs.oracle.com/javase/tutorial/deployment/jar/downman.html