ModuleNonBuiltinCLMain.java

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import static jdk.test.lib.Asserts.*;

import java.lang.reflect.Layer;
import java.lang.module.Configuration;
import java.lang.module.ModuleDescriptor;
import java.lang.module.ModuleFinder;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

//
// ClassLoader1 --> defines m1 --> packages p1
// ClassLoader2 --> defines m2 --> packages p2
// Java System Class Loader --> defines m3 --> packages p3
//
// m1 can read m2
// package p2 in m2 is exported to m1 and m3
//
// class p1.c1 defined in m1 tries to access p2.c2 defined in m2
// Access allowed since m1 can read m2 and package p2 is exported to m1.
//
public class ModuleNonBuiltinCLMain {

    // Create a Layer over the boot layer.
    // Define modules within this layer to test access between
    // publically defined classes within packages of those modules.
    public void createLayerOnBoot() throws Throwable {

        // Define module:     m1
        // Can read:          java.base, m2
        // Packages:          p1
        // Packages exported: p1 is exported to unqualifiedly
        ModuleDescriptor descriptor_m1 =
                ModuleDescriptor.module("m1")
                        .requires("java.base")
                        .requires("m2")
                        .exports("p1")
                        .build();

        // Define module:     m2
        // Can read:          java.base, m3
        // Packages:          p2
        // Packages exported: package p2 is exported to m1 and m3
        Set<String> targets = new HashSet<>();
        targets.add("m1");
        targets.add("m3");
        ModuleDescriptor descriptor_m2 =
                ModuleDescriptor.module("m2")
                        .requires("java.base")
                        .requires("m3")
                        .exports("p2", targets)
                        .build();

        // Define module:     m3
        // Can read:          java.base
        // Packages:          p3
        // Packages exported: none
        ModuleDescriptor descriptor_m3 =
                ModuleDescriptor.module("m3")
                        .requires("java.base")
                        .build();

        // Set up a ModuleFinder containing all modules for this layer.
        ModuleFinder finder = ModuleLibrary.of(descriptor_m1, descriptor_m2, descriptor_m3);

        // Resolves "m1"
        Configuration cf = Layer.boot()
                .configuration()
                .resolveRequires(finder, ModuleFinder.of(), Set.of("m1"));

        // map each module to differing user defined class loaders for this test
        Map<String, ClassLoader> map = new HashMap<>();
        Loader1 cl1 = new Loader1();
        Loader2 cl2 = new Loader2();
        ClassLoader cl3 = ClassLoader.getSystemClassLoader();
        map.put("m1", cl1);
        map.put("m2", cl2);
        map.put("m3", cl3);

        // Create Layer that contains m1 & m2
        Layer layer = Layer.boot().defineModules(cf, map::get);
        assertTrue(layer.findLoader("m1") == cl1);
        assertTrue(layer.findLoader("m2") == cl2);
        assertTrue(layer.findLoader("m3") == cl3);
        assertTrue(layer.findLoader("java.base") == null);

        // now use the same loader to load class p1.c1
        Class p1_c1_class = cl1.loadClass("p1.c1");
        try {
            p1_c1_class.newInstance();
        } catch (IllegalAccessError e) {
            throw new RuntimeException("Test Failed, an IAE should not be thrown since p2 is exported qualifiedly to m1");
        }
    }

    public static void main(String args[]) throws Throwable {
      ModuleNonBuiltinCLMain test = new ModuleNonBuiltinCLMain();
      test.createLayerOnBoot();
    }

    static class Loader1 extends ClassLoader { }
    static class Loader2 extends ClassLoader { }
}