Classpath

When a Java program executes the Java runtime environment (JRE) will locate and load classes as they are requested by the program's execution path. The JRE locates Java classes by searching the Java classpath in the order it is defined. The JRE supports a single, global classpath.

In contrast NetKernel employs a Java class search strategy that is context dependent and tightly managed. This control allows NetKernel to provide many benefits, such as module isolation and version management. Each module in NetKernel has its own classloader. The dynamic linking of modules creates a structured and ordered Java classpath. A module's classloader starts a local search for classes and then progressively broadens the scope through the module context.

The NetKernel class and resource resolution order is as follows:

1. The local module
2. Any JAR files located in the local module's lib/ directory - order is not defined.
3. The Java packages exported on the public interface of any modules imported into the local module in order of import.
4. The parent classloader - generally this is the module superstack context from which the currently executing NetKernel request originated.
5. The NetKernel core
6. The [install]/lib/ext/ directory of the NetKernel installation.
7. The Java Virtual Machine

Classpath Trace Tool

The Class Trace Tool can provide detailed class resolution information for a given class in a specified module context.