[MNG-8024] Make WrapperProperties and WrapperList serializable

maven-model/src/test/java/org/apache/maven/model/SerializationTest.java

@@ -54,4 +54,18 @@ void testModelSerialization() throws Exception {
 
         assertNotNull(build2);
     }
+
+    @Test
+    void testModelPropertiesAndListSerialization() throws Exception {
+        Model model;
+        try (InputStream is = getClass().getResourceAsStream("/xml/pom.xml")) {
+            model = new MavenXpp3Reader().read(is);
+        }
+
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        try (ObjectOutputStream oos = new ObjectOutputStream(baos)) {
+            oos.writeObject(model.getProperties());
+            oos.writeObject(model.getBuild().getPlugins());
+        }
+    }
 }

src/mdo/java/WrapperList.java

@@ -18,6 +18,8 @@
  */
 package ${package};
 
+import java.io.ObjectStreamException;
+import java.io.Serializable;
 import java.util.AbstractList;
 import java.util.ArrayList;
 import java.util.List;
@@ -26,7 +28,7 @@
 import java.util.function.Function;
 import java.util.function.Supplier;
 
-class WrapperList<T, U> extends AbstractList<T> {
+class WrapperList<T, U> extends AbstractList<T> implements Serializable {
     private final Supplier<List<U>> getter;
     private final Consumer<List<U>> setter;
     private final Function<U, T> mapper;
@@ -102,4 +104,8 @@ public T remove(int index) {
             return mapper.apply(getter.get().remove(index));
         }
     }
+
+    private Object writeReplace() throws ObjectStreamException {
+        return new ArrayList<T>(this);
+    }
 }

src/mdo/java/WrapperProperties.java

@@ -330,4 +330,11 @@ public void storeToXML(OutputStream os, String comment, String encoding) throws
         props.putAll(getter.get());
         props.storeToXML(os, comment, encoding);
     }
+
+
+    private Object writeReplace() throws java.io.ObjectStreamException {
+        Properties props = new Properties();
+        props.putAll(getter.get());
+        return props;
+    }
 }