add missing @nullable annotations

Author: SylvainJuge

instrumentation/apache-httpclient/apache-httpclient-5.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/apachehttpclient/v5_0/ApacheHttpClientHelper.java

@@ -10,11 +10,12 @@
 import io.opentelemetry.context.Context;
 import org.apache.hc.core5.http.ClassicHttpRequest;
 import org.apache.hc.core5.http.HttpResponse;
+import javax.annotation.Nullable;
 
 public class ApacheHttpClientHelper {
 
   public static void doMethodExit(
-      Context context, ClassicHttpRequest request, Object result, Throwable throwable) {
+      Context context, ClassicHttpRequest request, @Nullable Object result, @Nullable Throwable throwable) {
     if (throwable != null) {
       instrumenter().end(context, request, null, throwable);
     } else if (result instanceof HttpResponse) {

instrumentation/apache-httpclient/apache-httpclient-5.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/apachehttpclient/v5_0/ApacheHttpClientInstrumentation.java

@@ -149,7 +149,7 @@ public static AdviceScope start(ClassicHttpRequest request) {
       return new AdviceScope(request, parentContext, context, context.makeCurrent());
     }
 
-    public void end(Object result, Throwable throwable) {
+    public void end(@Nullable Object result, @Nullable Throwable throwable) {
       scope.close();
       ApacheHttpClientHelper.doMethodExit(context, request, result, throwable);
     }
@@ -172,7 +172,7 @@ public static AdviceScope methodEnter(@Advice.Argument(0) ClassicHttpRequest req
     @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
     public static void methodExit(
         @Advice.Return Object result,
-        @Advice.Thrown Throwable throwable,
+        @Advice.Thrown @Nullable Throwable throwable,
         @Advice.Enter @Nullable AdviceScope scope) {
 
       if (scope != null) {
@@ -206,8 +206,8 @@ public static Object[] methodEnter(
     @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
     public static void methodExit(
         @Advice.Argument(0) ClassicHttpRequest request,
-        @Advice.Return Object result,
-        @Advice.Thrown Throwable throwable,
+        @Advice.Return @Nullable Object result,
+        @Advice.Thrown @Nullable Throwable throwable,
         @Advice.Enter Object[] enterResult) {
 
       AdviceScope scope = (AdviceScope) enterResult[0];
@@ -242,8 +242,8 @@ public static Object[] methodEnter(
     @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
     public static void methodExit(
         @Advice.Argument(0) ClassicHttpRequest request,
-        @Advice.Return Object result,
-        @Advice.Thrown Throwable throwable,
+        @Advice.Return @Nullable Object result,
+        @Advice.Thrown @Nullable Throwable throwable,
         @Advice.Enter Object[] enterResult) {
 
       AdviceScope scope = (AdviceScope) enterResult[0];
@@ -267,7 +267,7 @@ public static AdviceScope methodEnter(
     @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
     public static void methodExit(
         @Advice.Return Object result,
-        @Advice.Thrown Throwable throwable,
+        @Advice.Thrown @Nullable Throwable throwable,
         @Advice.Enter @Nullable AdviceScope scope) {
 
       if (scope != null) {
@@ -302,8 +302,8 @@ public static Object[] methodEnter(
 
     @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
     public static void methodExit(
-        @Advice.Return Object result,
-        @Advice.Thrown Throwable throwable,
+        @Advice.Return @Nullable Object result,
+        @Advice.Thrown @Nullable Throwable throwable,
         @Advice.Enter Object[] enterResult) {
 
       AdviceScope scope = (AdviceScope) enterResult[0];