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javareflectionjarclassloaderreflections

Reflections and multiple jars

I got two jar files, lets call them domain.jar and scanner.jar. In the scanner jar I have used Reflections library like so:

Reflections reflections = new Reflections(new ConfigurationBuilder().addUrls(ClasspathHelper.forPackage(packageName)).setScanners(new SubTypesScanner(false)));
Set<Class<?>> subTypesOf = reflections.getSubTypesOf(Object.class);

where if I point the packageName to packages inside the scanner.jar everything works fine, but if I try to find classes from the domain.jar it always returns empty set.

I run it with java -cp domain.jar -jar scanner.jar

Any idea what I'm doing wrong? From Reflections usage examples it supports multimodule projects so this should be possible.

Solution

  • The -cp and -jar options are mutually exclusive. Either you use -jar, and the classpath is composed from the jar file and all the other jar files referenced in its manefest, or you use -cp and list all the jars that must be part of the classpath.

    The documentation about the -jar option says:

    When you use this option, the JAR file is the source of all user classes, and other user class path settings are ignored.

    So, try with

    java -cp domain.jar;scanner.jar your.fully.qualified.MainClass