DubboComponentScan cannot backward support for alibaba @Service and @Reference.

dubbo-common/src/main/java/org/apache/dubbo/common/utils/PojoUtils.java

@@ -366,7 +366,7 @@ private static Object realize0(Object pojo, Class<?> type, Type genericType, fin
                 history.put(pojo, dest);
                 for (Object obj : src) {
                     Type keyType = getGenericClassByIndex(genericType, 0);
-                    Class<?> keyClazz = obj.getClass();
+                    Class<?> keyClazz = obj == null ? null : obj.getClass();
                     if (keyType instanceof Class) {
                         keyClazz = (Class<?>) keyType;
                     }

dubbo-common/src/test/java/org/apache/dubbo/common/utils/PojoUtilsTest.java

@@ -37,6 +37,7 @@
 import java.util.LinkedHashMap;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.HashSet;
 import java.util.Map;
 import java.util.UUID;
 
@@ -682,6 +683,24 @@ public void testDateTimeTimestamp() throws Exception {
         assertEquals(dateTimeStr, new SimpleDateFormat(dateFormat[0]).format(timestamp));
     }
 
+    @Test
+    public void testRealizeCollectionWithNullElement() {
+        LinkedList<String> listStr = new LinkedList<>();
+        listStr.add("arrayValue");
+        listStr.add(null);
+        HashSet<String> setStr = new HashSet<>();
+        setStr.add("setValue");
+        setStr.add(null);
+
+        Object listResult = PojoUtils.realize(listStr, LinkedList.class);
+        assertEquals(LinkedList.class, listResult.getClass());
+        assertEquals(listResult, listStr);
+
+        Object setResult = PojoUtils.realize(setStr, HashSet.class);
+        assertEquals(HashSet.class, setResult.getClass());
+        assertEquals(setResult, setStr);
+    }
+
     public enum Day {
         SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY
     }

dubbo-compatible/src/main/java/com/alibaba/dubbo/config/spring/context/annotation/EnableDubbo.java

@@ -18,7 +18,7 @@
 package com.alibaba.dubbo.config.spring.context.annotation;
 
 import org.apache.dubbo.config.AbstractConfig;
-import org.apache.dubbo.config.spring.context.annotation.CompatibleDubboComponentScan;
+import org.apache.dubbo.config.spring.context.annotation.DubboComponentScan;
 import org.apache.dubbo.config.spring.context.annotation.EnableDubboConfig;
 
 import org.springframework.core.annotation.AliasFor;
@@ -36,7 +36,7 @@
 @Inherited
 @Documented
 @EnableDubboConfig
-@CompatibleDubboComponentScan
+@DubboComponentScan
 public @interface EnableDubbo {
 
     /**
@@ -46,9 +46,9 @@
      * package names.
      *
      * @return the base packages to scan
-     * @see CompatibleDubboComponentScan#basePackages()
+     * @see DubboComponentScan#basePackages()
      */
-    @AliasFor(annotation = CompatibleDubboComponentScan.class, attribute = "basePackages")
+    @AliasFor(annotation = DubboComponentScan.class, attribute = "basePackages")
     String[] scanBasePackages() default {};
 
     /**
@@ -57,9 +57,9 @@
      * scanned.
      *
      * @return classes from the base packages to scan
-     * @see CompatibleDubboComponentScan#basePackageClasses
+     * @see DubboComponentScan#basePackageClasses
      */
-    @AliasFor(annotation = CompatibleDubboComponentScan.class, attribute = "basePackageClasses")
+    @AliasFor(annotation = DubboComponentScan.class, attribute = "basePackageClasses")
     Class<?>[] scanBasePackageClasses() default {};