modify some nonstandard code

easyexcel-core/src/main/java/com/alibaba/excel/cache/selector/EternalReadCacheSelector.java

@@ -10,7 +10,7 @@ import com.alibaba.excel.cache.ReadCache;
  * @author Jiaju Zhuang
  **/
 public class EternalReadCacheSelector implements ReadCacheSelector {
-    private ReadCache readCache;
+    private final ReadCache readCache;
 
     public EternalReadCacheSelector(ReadCache readCache) {
         this.readCache = readCache;

easyexcel-test/src/test/java/com/alibaba/easyexcel/test/core/encrypt/EncryptDataListener.java

@@ -16,7 +16,7 @@ import com.alibaba.fastjson.JSON;
  */
 public class EncryptDataListener extends AnalysisEventListener<EncryptData> {
     private static final Logger LOGGER = LoggerFactory.getLogger(EncryptDataListener.class);
-    List<EncryptData> list = new ArrayList<EncryptData>();
+    private final List<EncryptData> list = new ArrayList<>();
 
     @Override
     public void invoke(EncryptData data, AnalysisContext context) {