[BEANUTILS-541] FluentPropertyBeanIntrospector concurrency issue (backport to 1.X)

src/main/java/org/apache/commons/beanutils/FluentPropertyBeanIntrospector.java

@@ -80,13 +80,6 @@ public class FluentPropertyBeanIntrospector implements BeanIntrospector {
     /** The default prefix for write methods. */
     public static final String DEFAULT_WRITE_METHOD_PREFIX = "set";
 
-    private static void clearDescriptorsCacheHierarchy(final Class<?> cls) {
-        if (cls != null && cls != Object.class) {
-            Introspector.flushFromCaches(cls);
-            clearDescriptorsCacheHierarchy(cls.getSuperclass());
-        }
-    }
-
     /** The logger. */
     private final Log log = LogFactory.getLog(getClass());
 
@@ -162,11 +155,13 @@ public void introspect(final IntrospectionContext icontext)
                         icontext.addPropertyDescriptor(createFluentPropertyDescritor(
                                 m, propertyName));
                     } else if (pd.getWriteMethod() == null) {
-                        // We change statically cached PropertyDescriptor, it may affect
-                        // other subclasses of targetClass supertype.
+                        // We should not change statically cached PropertyDescriptor as it can be from super-type,
+                        // it may affect other subclasses of targetClass supertype.
                         // See BEANUTILS-541 for more details.
-                        clearDescriptorsCacheHierarchy(icontext.getTargetClass().getSuperclass());
-                        pd.setWriteMethod(m);
+                        PropertyDescriptor fluentPropertyDescriptor = new PropertyDescriptor(
+                                pd.getName(), pd.getReadMethod(), m);
+                        // replace existing (possibly inherited from super-class) to one specific to current class
+                        icontext.addPropertyDescriptor(fluentPropertyDescriptor);
                     }
                 } catch (final IntrospectionException e) {
                     log.info("Error when creating PropertyDescriptor for " + m

src/test/java/org/apache/commons/beanutils/bugs/Jira541TestCase.java

@@ -18,6 +18,12 @@
 
 import static org.junit.Assert.assertEquals;
 
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
 import org.apache.commons.beanutils.FluentPropertyBeanIntrospector;
 import org.apache.commons.beanutils.PropertyUtilsBean;
 import org.junit.Test;
@@ -42,6 +48,7 @@ public BaseType setField(final String objectName) {
             return this;
         }
     }
+
     public static class SubTypeA extends BaseType {
 
         @Override
@@ -61,6 +68,29 @@ public static class SubTypeB extends BaseType {
 
     @Test
     public void testFluentBeanIntrospectorOnOverriddenSetter() throws Exception {
+        testImpl();
+    }
+
+    @Test
+    public void testFluentBeanIntrospectorOnOverriddenSetterConcurrent() throws Exception {
+        ExecutorService executionService = Executors.newFixedThreadPool(256);
+        try {
+            List<Future<?>> futures = new ArrayList<>();
+            for (int i = 0; i < 10000; i++) {
+                futures.add(executionService.submit(() -> {
+                    testImpl();
+                    return null;
+                }));
+            }
+            for (Future<?> future : futures) {
+                future.get();
+            }
+        } finally {
+            executionService.shutdown();
+        }
+    }
+
+    private void testImpl() throws Exception {
         final PropertyUtilsBean propertyUtilsBean = new PropertyUtilsBean();
         propertyUtilsBean.addBeanIntrospector(new FluentPropertyBeanIntrospector());