lade.jpms
Create and run dynamic JPMS module layers from an in-memory classloader
Provides a ModuleFinder for InMemoryClassLoader, allowing dynamic JPMS from in-memory resources.
Uses JPMS API, so JDK >= 9 required.
Dependency Graph
Examples
The following example, creates ×3 in-memory JPMS JARs, creates a ModuleLayer and executes the application.
Create JARs
An API, Imp and App:
Archive api = archive()
.configured(
asJpmsModule()
.named("api")
.exporting(s -> true)
.autoRequiring()
)
.with(AcmeApi.class)
.toObjectModel();
Archive app = archive()
.configured(
asJpmsModule()
.named("app")
.autoRequiring()
.autoRequiring(fromArchives(api))
.exporting(s -> true)
.using(AcmeApi.class)
.launching(AcmeApp.class)
)
.toObjectModel();
Archive imp = archive()
.configured(
asJpmsModule()
.named("imp")
.autoRequiring()
.autoRequiring(fromArchives(api))
.providing(AcmeApi.class, AcmeImp.class)
).toObjectModel();
Create InMemoryClassLoader
Remembering to register the URLStreamHandler
Handler.addProtocolHandlerSystemProperty(); InMemoryClassLoader loader = inMemoryClassLoader() .jar(api.toByteArray()) .jar(imp.toByteArray()) .jar(app.toByteArray());
Create ModuleFinder and ModuleLayer
The ModuleLayer has in-memory modules resolved by the finder, and service dependencies are bound
ModuleFinder finder = new InMemoryModuleFinder(loader);
ModuleLayer parent = ModuleLayer.boot();
Configuration configuration = parent.configuration().resolveAndBind(
ModuleFinder.of(),
finder,
Set.of("app"));
ModuleLayer layer = parent.defineModulesWithOneLoader(configuration, loader);
Execute the App
Launch the application
Class<?> mainClass = layer.findLoader("app").loadClass(AcmeApp.class.getCanonicalName());
Method main = Methods.getMethod(mainClass, "main", String[].class)
.orElseThrow(NoSuchMethodError::new);
String you = "Dynamic & In-Mem";
String stdout = captureStdout(() -> main.invoke(null, new Object[] {new String[] {you}}));
String expectedResponse =
"module app: Acme Corp would like to say \"Hello\" to \"" +
you +
"\" (Terms and conditions apply)\n";
assertThat(stdout, is(equalTo(expectedResponse)));
View full source of associated test.
