diff --git a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/FeignBeanPostProcessor.java b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/FeignBeanPostProcessor.java
index 5f51d65f8..a341d02e2 100644
--- a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/FeignBeanPostProcessor.java
+++ b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/FeignBeanPostProcessor.java
@@ -33,7 +33,7 @@ import feign.codec.Decoder;
  *
  * @since 1.0.0
  */
-class FeignBeanPostProcessor implements BeanPostProcessor {
+final class FeignBeanPostProcessor implements BeanPostProcessor {
 
 	private final ApplicationEventPublisher publisher;
 	private final Tracer tracer;
diff --git a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/FeignRequestContext.java b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/FeignRequestContext.java
index b30d4c2a4..93bfdc694 100644
--- a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/FeignRequestContext.java
+++ b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/FeignRequestContext.java
@@ -28,7 +28,7 @@ import org.springframework.cloud.sleuth.Span;
  *
  * @since 1.0.0
  */
-class FeignRequestContext {
+final class FeignRequestContext {
 
 	private static final FeignRequestContext INSTANCE = new FeignRequestContext();
 
@@ -36,7 +36,7 @@ class FeignRequestContext {
 
 	private static final ThreadLocal<SpanHolder> THREAD_LOCAL = new ThreadLocal<>();
 
-	private static class SpanHolder {
+	private static final class SpanHolder {
 		final Span span;
 		final boolean retried;
 
diff --git a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/SleuthFeignBuilder.java b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/SleuthFeignBuilder.java
index d80ffe53c..0b7420102 100644
--- a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/SleuthFeignBuilder.java
+++ b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/SleuthFeignBuilder.java
@@ -31,7 +31,9 @@ import feign.hystrix.HystrixFeign;
  *
  * @since 1.0.0
  */
-class SleuthFeignBuilder {
+final class SleuthFeignBuilder {
+
+	private SleuthFeignBuilder() {}
 
 	static Feign.Builder builder(ApplicationEventPublisher publisher, Tracer tracer) {
 		return HystrixFeign.builder()
diff --git a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignClient.java b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignClient.java
index 00bc76ce2..ffaa2d1e3 100644
--- a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignClient.java
+++ b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignClient.java
@@ -34,7 +34,7 @@ import feign.Response;
  *
  * @since 1.0.0
  */
-class TraceFeignClient extends FeignEventPublisher implements Client {
+final class TraceFeignClient extends FeignEventPublisher implements Client {
 
 	private final Client delegate;
 
diff --git a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignDecoder.java b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignDecoder.java
index d13d7f7c8..149e81445 100644
--- a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignDecoder.java
+++ b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignDecoder.java
@@ -34,15 +34,16 @@ import feign.codec.Decoder;
  *
  * @since 1.0.0
  */
-class TraceFeignDecoder extends FeignEventPublisher implements Decoder {
+final class TraceFeignDecoder extends FeignEventPublisher implements Decoder {
 
 	private final Decoder delegate;
 
-	public TraceFeignDecoder(ApplicationEventPublisher publisher, Tracer tracer) {
+	TraceFeignDecoder(ApplicationEventPublisher publisher, Tracer tracer) {
 		super(publisher, tracer);
 		this.delegate = new Decoder.Default();
 	}
-	public TraceFeignDecoder(ApplicationEventPublisher publisher, Tracer tracer, Decoder delegate) {
+
+	TraceFeignDecoder(ApplicationEventPublisher publisher, Tracer tracer, Decoder delegate) {
 		super(publisher, tracer);
 		this.delegate = delegate;
 	}
diff --git a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignRequestInterceptor.java b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignRequestInterceptor.java
index 6aff3af32..a15fdb28d 100644
--- a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignRequestInterceptor.java
+++ b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignRequestInterceptor.java
@@ -37,7 +37,7 @@ import feign.RequestTemplate;
  *
  * @since 1.0.0
  */
-class TraceFeignRequestInterceptor implements RequestInterceptor,
+final class TraceFeignRequestInterceptor implements RequestInterceptor,
 		ApplicationEventPublisherAware {
 
 	private final Tracer tracer;
@@ -45,7 +45,7 @@ class TraceFeignRequestInterceptor implements RequestInterceptor,
 
 	private ApplicationEventPublisher publisher;
 
-	public TraceFeignRequestInterceptor(Tracer tracer) {
+	TraceFeignRequestInterceptor(Tracer tracer) {
 		this.tracer = tracer;
 	}
 
diff --git a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignRetryer.java b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignRetryer.java
index d8300c618..4919dd677 100644
--- a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignRetryer.java
+++ b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TraceFeignRetryer.java
@@ -31,17 +31,17 @@ import feign.Retryer;
  *
  * @since 1.0.0
  */
-class TraceFeignRetryer implements Retryer {
+final class TraceFeignRetryer implements Retryer {
 
 	private final Tracer tracer;
 	private final FeignRequestContext feignRequestContext = FeignRequestContext.getInstance();
 	private final Retryer delegate;
 
-	public TraceFeignRetryer(Tracer tracer) {
+	TraceFeignRetryer(Tracer tracer) {
 		this(tracer, new Retryer.Default());
 	}
 
-	public TraceFeignRetryer(Tracer tracer, Retryer delegate) {
+	TraceFeignRetryer(Tracer tracer, Retryer delegate) {
 		this.tracer = tracer;
 		this.delegate = delegate;
 	}