Suppress case variants of mapped names in isPropertySuppressed

src/main/java/org/apache/commons/beanutils2/MappedPropertyDescriptor.java

@@ -162,7 +162,7 @@ private Class<?> reLoadClass(final String name) {
      *
      * @param s The property name
      */
-    private static String capitalizePropertyName(final String s) {
+    static String capitalizePropertyName(final String s) {
         if (s.isEmpty()) {
             return s;
         }

src/main/java/org/apache/commons/beanutils2/PropertyUtilsBean.java

@@ -1068,15 +1068,21 @@ private Object invokeMethod(final Method method, final Object bean, final Object
     /**
      * Tests whether a property name has been removed by a registered {@link SuppressPropertiesBeanIntrospector}. The mapped-descriptor fallback in
      * {@link #getPropertyDescriptor(Object, String)} bypasses the introspection pipeline, so suppressed mapped property names must be filtered explicitly.
+     * {@link MappedPropertyDescriptor} derives its accessor names from the capitalized property name, so names differing only in the case of their first
+     * character resolve the same accessors and are compared on that capitalized form here.
      *
      * @param name The property name to test.
      * @return {@code true} if the name is suppressed by an introspector.
      */
     private boolean isPropertySuppressed(final String name) {
+        final String base = MappedPropertyDescriptor.capitalizePropertyName(name);
         for (final BeanIntrospector introspector : introspectors) {
-            if (introspector instanceof SuppressPropertiesBeanIntrospector
-                    && ((SuppressPropertiesBeanIntrospector) introspector).getSuppressedProperties().contains(name)) {
-                return true;
+            if (introspector instanceof SuppressPropertiesBeanIntrospector) {
+                for (final String suppressed : ((SuppressPropertiesBeanIntrospector) introspector).getSuppressedProperties()) {
+                    if (base.equals(MappedPropertyDescriptor.capitalizePropertyName(suppressed))) {
+                        return true;
+                    }
+                }
             }
         }
         return false;

src/test/java/org/apache/commons/beanutils2/PropertyUtilsTest.java

@@ -315,6 +315,23 @@ void testCustomIntrospectionSuppressedMappedProperty() throws Exception {
         assertEquals("First Value", unsuppressed.getProperty(bean, "mappedProperty(First Key)"), "Mapped property should be readable when not suppressed");
     }
 
+    /**
+     * {@link MappedPropertyDescriptor} capitalizes the first character of the property name to build the accessor names, so {@code MappedProperty(key)}
+     * resolves the same {@code getMappedProperty}/{@code setMappedProperty} pair as {@code mappedProperty(key)} and must be suppressed with it.
+     */
+    @Test
+    void testCustomIntrospectionSuppressedMappedPropertyCaseVariant() throws Exception {
+        final PropertyUtilsBean pub = new PropertyUtilsBean();
+        pub.addBeanIntrospector(new SuppressPropertiesBeanIntrospector(Arrays.asList("mappedProperty")));
+
+        assertNull(pub.getPropertyDescriptor(bean, "MappedProperty"), "Case variant of a suppressed mapped property should have no descriptor");
+        assertThrows(NoSuchMethodException.class, () -> pub.getProperty(bean, "MappedProperty(First Key)"),
+                "Case variant of a suppressed mapped property must not be readable");
+        assertThrows(NoSuchMethodException.class, () -> pub.setProperty(bean, "MappedProperty(First Key)", "changed"),
+                "Case variant of a suppressed mapped property must not be writable");
+        assertEquals("First Value", bean.getMappedProperty("First Key"), "Suppressed mapped property must be unchanged");
+    }
+
     /**
      * Test the describe() method.
      */