#62 Support Java 21

* run CI build on Java 21 also
* use ObjectInputStream for testing with all Java versions
* update Maven JAR Plugin to 3.3.0

.github/workflows/maven.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java-version: [ 8, 11, 17 ]
+        java-version: [ 8, 11, 17, 21 ]
         os: [ ubuntu-latest, windows-latest ]
     runs-on: ${{ matrix.os }}
     steps:

pom.xml

@@ -89,6 +89,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-jar-plugin</artifactId>
+        <version>3.3.0</version>
         <configuration>
           <archive>
             <manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestFile>

src/test/java/org/ops4j/pax/tinybundles/test/ClassFinderTest.java

@@ -18,10 +18,10 @@
 package org.ops4j.pax.tinybundles.test;
 
 import java.io.IOException;
+import java.io.ObjectInputStream;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.regex.Pattern;
 
 import aQute.bnd.build.Container;
 import org.junit.Before;
@@ -81,21 +81,22 @@ public void findAnonymousClasses() throws IOException {
 
     @Test
     public void findAllEmbeddedClassesFromJreClass() throws IOException {
-        final Class<?> clazz = Pattern.class;
+        final Class<?> clazz = ObjectInputStream.class;
         final Collection<ClassDescriptor> descriptors = finder.findAllEmbeddedClasses(clazz);
         verify(descriptors, false,
-            "java/util/regex/Pattern$1.class",
-            "java/util/regex/Pattern$CharProperty.class",
-            "java/util/regex/Pattern$Dollar.class"
+            "java/io/ObjectInputStream$1.class",
+            "java/io/ObjectInputStream$ValidationList$1.class",
+            "java/io/ObjectInputStream$ValidationList$Callback.class",
+            "java/io/ObjectInputStream$ValidationList.class"
         );
     }
 
     @Test
     public void findAnonymousClassesFromJreClass() throws IOException {
-        final Class<?> clazz = Pattern.class;
+        final Class<?> clazz = ObjectInputStream.class;
         final Collection<ClassDescriptor> descriptors = finder.findAnonymousClasses(clazz);
         verify(descriptors, false,
-            "java/util/regex/Pattern$1.class"
+            "java/io/ObjectInputStream$1.class"
         );
     }