Harden candidate property descriptor checks

Tighten `isCandidateProperty` to reject null descriptors and properties without a read method, instead of treating missing getters as bindable candidates. Tests were updated to cover null and missing-property cases, verify Object-derived `class` is excluded, and confirm a real bindable property (`ServerProperties.port`) is still accepted.

Author: mercyblitz

microsphere-spring-boot-core/src/main/java/io/microsphere/spring/boot/context/properties/bind/ConfigurationPropertiesBeanContext.java

@@ -543,8 +543,14 @@ static String buildPropertyPath(String propertyName, @Nullable String nestedPath
      * @return {@code true} if the property is a binding candidate, {@code false} otherwise
      */
     static boolean isCandidateProperty(PropertyDescriptor descriptor) {
+        if (descriptor == null) {
+            return false;
+        }
         Method readMethod = descriptor.getReadMethod();
-        return readMethod == null || !Object.class.equals(readMethod.getDeclaringClass());
+        if (readMethod == null) {
+            return false;
+        }
+        return !Object.class.equals(readMethod.getDeclaringClass());
     }
 
     /**

microsphere-spring-boot-core/src/test/java/io/microsphere/spring/boot/context/properties/bind/ConfigurationPropertiesBeanContextTest.java

@@ -146,11 +146,18 @@ void testGetInstance() {
 
     @Test
     void testIsCandidateProperty() {
+        assertFalse(isCandidateProperty(null));
         PropertyDescriptor descriptor = getPropertyDescriptor(ConfigurationPropertiesBeanContextTest.class, "name");
-        assertTrue(isCandidateProperty(descriptor));
+        assertFalse(isCandidateProperty(descriptor));
+
+        descriptor = getPropertyDescriptor(ConfigurationPropertiesBeanContextTest.class, "not-found");
+        assertFalse(isCandidateProperty(descriptor));
 
         descriptor = getPropertyDescriptor(ConfigurationPropertiesBeanContextTest.class, "class");
         assertFalse(isCandidateProperty(descriptor));
+
+        descriptor = getPropertyDescriptor(ServerProperties.class, "port");
+        assertTrue(isCandidateProperty(descriptor));
     }
 
     @Test