The problem is that your module path contains the same package (javax.annotation) in different modules (java.xml.ws.annotation and tomcat.embed.core), which the module system forbids in order to make configurations more reliable. This is called a split package. The module system tells you as much when listing all the modules that read (i.e. “see”) that package twice. … Read more
The module system has mainly the following impact on the code: A package can only be accessed from one module (Nested packages are treated as separate, so even though the package java.util is in the module java.base, the package java.util.logging can be in the module java.logging) You can only access public fields and methods of … Read more
You can use class path and module path in parallel, but there are a few details to consider. Dependency Module Path ~> Class Path Explicit modules (JARs with a module descriptor on the module path) can not read the unnamed module (JARs on the class path) – that was done on purpose to prevent modular … Read more