Fix #116 : Java 16 support for ReflectionUtils (and Java 11 no warning)

Author: axel3rd

src/main/java/org/codehaus/plexus/util/ReflectionUtils.java

@@ -32,7 +32,6 @@
  * @author <a href="mailto:[email protected]">Michal Maczka</a>
  * @author <a href="mailto:[email protected]">Jesse McConnell</a>
  * @author <a href="mailto:[email protected]">Trygve Laugst&oslash;l</a>
- *
  */
 public final class ReflectionUtils
 {
@@ -126,7 +125,7 @@ public static List<Method> getSetters( Class<?> clazz )
 
     /**
      * @param method the method
-     * @return  the class of the argument to the setter. Will throw an RuntimeException if the method isn't a setter.
+     * @return the class of the argument to the setter. Will throw an RuntimeException if the method isn't a setter.
      */
     public static Class<?> getSetterType( Method method )
     {
@@ -163,6 +162,7 @@ public static void setVariableValueInObject( Object object, String variable, Obj
 
     /**
      * Generates a map of the fields and values on a given object, also pulls from superclasses
+     * 
      * @param variable field name
      * @param object the object to generate the list of fields from
      * @return map containing the fields and their values
@@ -218,6 +218,14 @@ private static void gatherVariablesAndValuesIncludingSuperclasses( Object object
 
         Class<?> clazz = object.getClass();
 
+        if ( Float.parseFloat( System.getProperty( "java.specification.version" ) ) >= 11
+            && Class.class.getCanonicalName().equals( clazz.getCanonicalName() ) )
+        {
+            // Updating Class fields accessibility is forbidden on Java 16 (and throws warning from version 11)
+            // No concrete use case to modify accessibility at this level
+            return;
+        }
+
         Field[] fields = clazz.getDeclaredFields();
 
         AccessibleObject.setAccessible( fields, true );