Apply suggestions from code review

Co-authored-by: SylvainJuge <[email protected]>

Author: trask

instrumentation/lettuce/lettuce-4.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/lettuce/v4_0/LettuceAsyncCommandsInstrumentation.java

@@ -76,9 +76,9 @@ public static AdviceScope onEnter(@Advice.Argument(0) RedisCommand<?, ?, ?> comm
     @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
     public static void onExit(
         @Advice.Argument(0) RedisCommand<?, ?, ?> command,
-        @Advice.Thrown Throwable throwable,
-        @Advice.Return AsyncCommand<?, ?, ?> asyncCommand,
-        @Advice.Enter AdviceScope adviceScope) {
+        @Advice.Thrown @Nullable Throwable throwable,
+        @Advice.Return @Nullable AsyncCommand<?, ?, ?> asyncCommand,
+        @Advice.Enter @Nullable AdviceScope adviceScope) {
       if (adviceScope != null) {
         adviceScope.end(throwable, command, asyncCommand);
       }

instrumentation/lettuce/lettuce-4.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/lettuce/v4_0/LettuceConnectInstrumentation.java

@@ -67,7 +67,7 @@ public static AdviceScope onEnter(@Advice.Argument(1) RedisURI redisUri) {
     public static void onExit(
         @Advice.Argument(1) RedisURI redisUri,
         @Advice.Thrown @Nullable Throwable throwable,
-        @Advice.Enter AdviceScope adviceScope) {
+        @Advice.Enter @Nullable AdviceScope adviceScope) {
       if (adviceScope != null) {
         adviceScope.end(throwable, redisUri);
       }

instrumentation/lettuce/lettuce-5.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/lettuce/v5_0/LettuceAsyncCommandsInstrumentation.java

@@ -89,8 +89,8 @@ public static AdviceScope onEnter(@Advice.Argument(0) RedisCommand<?, ?, ?> comm
     public static void stopSpan(
         @Advice.Argument(0) RedisCommand<?, ?, ?> command,
         @Advice.Thrown @Nullable Throwable throwable,
-        @Advice.Return AsyncCommand<?, ?, ?> asyncCommand,
-        @Advice.Enter AdviceScope adviceScope) {
+        @Advice.Return @Nullable AsyncCommand<?, ?, ?> asyncCommand,
+        @Advice.Enter @Nullable AdviceScope adviceScope) {
 
       if (adviceScope != null) {
         adviceScope.end(throwable, command, asyncCommand);

instrumentation/lettuce/lettuce-5.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/lettuce/v5_0/LettuceClientInstrumentation.java

@@ -85,8 +85,8 @@ public static AdviceScope onEnter(@Advice.Argument(1) RedisURI redisUri) {
     public static void stopSpan(
         @Advice.Argument(1) RedisURI redisUri,
         @Advice.Thrown @Nullable Throwable throwable,
-        @Advice.Return ConnectionFuture<?> connectionFuture,
-        @Advice.Enter AdviceScope adviceScope) {
+        @Advice.Return @Nullable ConnectionFuture<?> connectionFuture,
+        @Advice.Enter @Nullable AdviceScope adviceScope) {
       if (adviceScope != null) {
         adviceScope.end(throwable, redisUri, connectionFuture);
       }