diff --git a/spring-cloud-alibaba-starters/spring-cloud-alibaba-sentinel-datasource/src/main/java/com/alibaba/cloud/sentinel/datasource/config/DataSourcePropertiesConfiguration.java b/spring-cloud-alibaba-starters/spring-cloud-alibaba-sentinel-datasource/src/main/java/com/alibaba/cloud/sentinel/datasource/config/DataSourcePropertiesConfiguration.java
index a0a5526f..330a0a04 100644
--- a/spring-cloud-alibaba-starters/spring-cloud-alibaba-sentinel-datasource/src/main/java/com/alibaba/cloud/sentinel/datasource/config/DataSourcePropertiesConfiguration.java
+++ b/spring-cloud-alibaba-starters/spring-cloud-alibaba-sentinel-datasource/src/main/java/com/alibaba/cloud/sentinel/datasource/config/DataSourcePropertiesConfiguration.java
@@ -132,7 +132,6 @@ public class DataSourcePropertiesConfiguration {
 				if (!ObjectUtils.isEmpty(field.get(this))) {
 					return field.getName();
 				}
-				return null;
 			}
 			catch (IllegalAccessException e) {
 				// won't happen
diff --git a/spring-cloud-alibaba-starters/spring-cloud-alibaba-sentinel-datasource/src/main/java/com/alibaba/cloud/sentinel/datasource/converter/SentinelConverter.java b/spring-cloud-alibaba-starters/spring-cloud-alibaba-sentinel-datasource/src/main/java/com/alibaba/cloud/sentinel/datasource/converter/SentinelConverter.java
index 306dd1a0..1cc8c725 100644
--- a/spring-cloud-alibaba-starters/spring-cloud-alibaba-sentinel-datasource/src/main/java/com/alibaba/cloud/sentinel/datasource/converter/SentinelConverter.java
+++ b/spring-cloud-alibaba-starters/spring-cloud-alibaba-sentinel-datasource/src/main/java/com/alibaba/cloud/sentinel/datasource/converter/SentinelConverter.java
@@ -86,9 +86,8 @@ public abstract class SentinelConverter<T extends Object>
 					});
 
 			for (Object obj : sourceArray) {
-				String item = null;
 				try {
-					item = objectMapper.writeValueAsString(obj);
+					String item = objectMapper.writeValueAsString(obj);
 					Optional.ofNullable(convertRule(item))
 							.ifPresent(convertRule -> ruleCollection.add(convertRule));
 				}
diff --git a/spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-config/src/main/java/com/alibaba/cloud/nacos/endpoint/NacosConfigHealthIndicator.java b/spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-config/src/main/java/com/alibaba/cloud/nacos/endpoint/NacosConfigHealthIndicator.java
index affd0139..37e3c246 100644
--- a/spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-config/src/main/java/com/alibaba/cloud/nacos/endpoint/NacosConfigHealthIndicator.java
+++ b/spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-config/src/main/java/com/alibaba/cloud/nacos/endpoint/NacosConfigHealthIndicator.java
@@ -32,6 +32,16 @@ public class NacosConfigHealthIndicator extends AbstractHealthIndicator {
 
 	private final ConfigService configService;
 
+	/**
+	 * status up .
+	 */
+	private final String STATUS_UP = "UP";
+
+	/**
+	 * status down .
+	 */
+	private final String STATUS_DOWN = "DOWN";
+
 	public NacosConfigHealthIndicator(ConfigService configService) {
 		this.configService = configService;
 	}
@@ -43,10 +53,10 @@ public class NacosConfigHealthIndicator extends AbstractHealthIndicator {
 		// Set the status to Builder
 		builder.status(status);
 		switch (status) {
-		case "UP":
+		case STATUS_UP:
 			builder.up();
 			break;
-		case "DOWN":
+		case STATUS_DOWN:
 			builder.down();
 			break;
 		default:
diff --git a/spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-discovery/src/main/java/com/alibaba/cloud/nacos/discovery/actuate/health/NacosDiscoveryHealthIndicator.java b/spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-discovery/src/main/java/com/alibaba/cloud/nacos/discovery/actuate/health/NacosDiscoveryHealthIndicator.java
index 5a925ec3..32e523bb 100644
--- a/spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-discovery/src/main/java/com/alibaba/cloud/nacos/discovery/actuate/health/NacosDiscoveryHealthIndicator.java
+++ b/spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-discovery/src/main/java/com/alibaba/cloud/nacos/discovery/actuate/health/NacosDiscoveryHealthIndicator.java
@@ -31,6 +31,16 @@ import org.springframework.boot.actuate.health.HealthIndicator;
  */
 public class NacosDiscoveryHealthIndicator extends AbstractHealthIndicator {
 
+	/**
+	 * status up.
+	 */
+	private static final String STATUS_UP = "UP";
+
+	/**
+	 * status down.
+	 */
+	private static final String STATUS_DOWN = "DOWN";
+
 	private final NamingService namingService;
 
 	public NacosDiscoveryHealthIndicator(NamingService namingService) {
@@ -44,10 +54,10 @@ public class NacosDiscoveryHealthIndicator extends AbstractHealthIndicator {
 		// Set the status to Builder
 		builder.status(status);
 		switch (status) {
-		case "UP":
+		case STATUS_UP:
 			builder.up();
 			break;
-		case "DOWN":
+		case STATUS_DOWN:
 			builder.down();
 			break;
 		default: