diff --git a/instrumentation/spring/spring-web/spring-web-3.1/library/src/main/java/io/opentelemetry/instrumentation/spring/web/v3_1/SpringWebHttpAttributesGetter.java b/instrumentation/spring/spring-web/spring-web-3.1/library/src/main/java/io/opentelemetry/instrumentation/spring/web/v3_1/SpringWebHttpAttributesGetter.java
index 9f5446e510e4..481469051e3c 100644
--- a/instrumentation/spring/spring-web/spring-web-3.1/library/src/main/java/io/opentelemetry/instrumentation/spring/web/v3_1/SpringWebHttpAttributesGetter.java
+++ b/instrumentation/spring/spring-web/spring-web-3.1/library/src/main/java/io/opentelemetry/instrumentation/spring/web/v3_1/SpringWebHttpAttributesGetter.java
@@ -23,7 +23,7 @@ enum SpringWebHttpAttributesGetter
 
   @Nullable private static final MethodHandle GET_STATUS_CODE;
   @Nullable private static final MethodHandle STATUS_CODE_VALUE;
-  @Nullable private static final MethodHandle GET_HEADERS;
+  private static final MethodHandle GET_HEADERS;
 
   static {
     MethodHandles.Lookup lookup = MethodHandles.publicLookup();
@@ -58,21 +58,24 @@ enum SpringWebHttpAttributesGetter
 
     GET_STATUS_CODE = getStatusCode;
     STATUS_CODE_VALUE = statusCodeValue;
+    GET_HEADERS =
+        isSpring7OrNewer()
+            ? findGetHeadersMethod(MethodType.methodType(List.class, String.class))
+            : findGetHeadersMethod(MethodType.methodType(List.class, Object.class));
+  }
 
-    // since spring web 7.0
-    MethodHandle methodHandle =
-        findGetHeadersMethod(MethodType.methodType(List.class, String.class, List.class));
-    if (methodHandle == null) {
-      // up to spring web 7.0
-      methodHandle =
-          findGetHeadersMethod(MethodType.methodType(Object.class, Object.class, Object.class));
+  private static boolean isSpring7OrNewer() {
+    try {
+      Class.forName("org.springframework.core.Nullness");
+      return true;
+    } catch (ClassNotFoundException e) {
+      return false;
     }
-    GET_HEADERS = methodHandle;
   }
 
   private static MethodHandle findGetHeadersMethod(MethodType methodType) {
     try {
-      return MethodHandles.lookup().findVirtual(HttpHeaders.class, "getOrDefault", methodType);
+      return MethodHandles.lookup().findVirtual(HttpHeaders.class, "get", methodType);
     } catch (Throwable t) {
       return null;
     }
@@ -95,15 +98,16 @@ public List<String> getHttpRequestHeader(HttpRequest httpRequest, String name) {
   }
 
   @SuppressWarnings("unchecked") // casting MethodHandle.invoke result
-  private static List<String> getHeader(HttpHeaders headers, String name) {
-    if (GET_HEADERS != null) {
-      try {
-        return (List<String>) GET_HEADERS.invoke(headers, name, emptyList());
-      } catch (Throwable t) {
-        // ignore
+  static List<String> getHeader(HttpHeaders headers, String name) {
+    try {
+      List<String> result = (List<String>) GET_HEADERS.invoke(headers, name);
+      if (result == null) {
+        return emptyList();
       }
+      return result;
+    } catch (Throwable t) {
+      throw new IllegalStateException(t);
     }
-    return emptyList();
   }
 
   @Override
diff --git a/instrumentation/spring/spring-webflux/spring-webflux-5.3/library/src/main/java/io/opentelemetry/instrumentation/spring/webflux/v5_3/HeaderUtil.java b/instrumentation/spring/spring-webflux/spring-webflux-5.3/library/src/main/java/io/opentelemetry/instrumentation/spring/webflux/v5_3/HeaderUtil.java
index a1647d4f1526..336d484a5359 100644
--- a/instrumentation/spring/spring-webflux/spring-webflux-5.3/library/src/main/java/io/opentelemetry/instrumentation/spring/webflux/v5_3/HeaderUtil.java
+++ b/instrumentation/spring/spring-webflux/spring-webflux-5.3/library/src/main/java/io/opentelemetry/instrumentation/spring/webflux/v5_3/HeaderUtil.java
@@ -11,42 +11,46 @@
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
 import java.util.List;
-import javax.annotation.Nullable;
 import org.springframework.http.HttpHeaders;
 
 class HeaderUtil {
-  @Nullable private static final MethodHandle GET_HEADERS;
+  private static final MethodHandle GET_HEADERS;
 
   static {
-    // since spring web 7.0
-    MethodHandle methodHandle =
-        findGetHeadersMethod(MethodType.methodType(List.class, String.class, List.class));
-    if (methodHandle == null) {
-      // up to spring web 7.0
-      methodHandle =
-          findGetHeadersMethod(MethodType.methodType(Object.class, Object.class, Object.class));
+    GET_HEADERS =
+        isSpring7OrNewer()
+            ? findGetHeadersMethod(MethodType.methodType(List.class, String.class))
+            : findGetHeadersMethod(MethodType.methodType(List.class, Object.class));
+  }
+
+  private static boolean isSpring7OrNewer() {
+    try {
+      Class.forName("org.springframework.core.Nullness");
+      return true;
+    } catch (ClassNotFoundException e) {
+      return false;
     }
-    GET_HEADERS = methodHandle;
   }
 
   private static MethodHandle findGetHeadersMethod(MethodType methodType) {
     try {
-      return MethodHandles.lookup().findVirtual(HttpHeaders.class, "getOrDefault", methodType);
+      return MethodHandles.lookup().findVirtual(HttpHeaders.class, "get", methodType);
     } catch (Throwable t) {
-      return null;
+      throw new IllegalStateException(t);
     }
   }
 
   @SuppressWarnings("unchecked") // casting MethodHandle.invoke result
   static List<String> getHeader(HttpHeaders headers, String name) {
-    if (GET_HEADERS != null) {
-      try {
-        return (List<String>) GET_HEADERS.invoke(headers, name, emptyList());
-      } catch (Throwable t) {
-        // ignore
+    try {
+      List<String> result = (List<String>) GET_HEADERS.invoke(headers, name);
+      if (result == null) {
+        return emptyList();
       }
+      return result;
+    } catch (Throwable t) {
+      throw new IllegalStateException(t);
     }
-    return emptyList();
   }
 
   private HeaderUtil() {}
diff --git a/instrumentation/spring/spring-webflux/spring-webflux-5.3/library/src/main/java/io/opentelemetry/instrumentation/spring/webflux/v5_3/internal/WebClientHttpAttributesGetter.java b/instrumentation/spring/spring-webflux/spring-webflux-5.3/library/src/main/java/io/opentelemetry/instrumentation/spring/webflux/v5_3/internal/WebClientHttpAttributesGetter.java
index b8b61bf6e5e4..eb13a258901c 100644
--- a/instrumentation/spring/spring-webflux/spring-webflux-5.3/library/src/main/java/io/opentelemetry/instrumentation/spring/webflux/v5_3/internal/WebClientHttpAttributesGetter.java
+++ b/instrumentation/spring/spring-webflux/spring-webflux-5.3/library/src/main/java/io/opentelemetry/instrumentation/spring/webflux/v5_3/internal/WebClientHttpAttributesGetter.java
@@ -28,22 +28,26 @@ public enum WebClientHttpAttributesGetter
   private static final MethodHandle GET_HEADERS;
 
   static {
-    // since webflux 7.0
-    MethodHandle methodHandle =
-        findGetHeadersMethod(MethodType.methodType(List.class, String.class, List.class));
-    if (methodHandle == null) {
-      // up to webflux 7.0
-      methodHandle =
-          findGetHeadersMethod(MethodType.methodType(Object.class, Object.class, Object.class));
+    GET_HEADERS =
+        isSpring7OrNewer()
+            ? findGetHeadersMethod(MethodType.methodType(List.class, String.class))
+            : findGetHeadersMethod(MethodType.methodType(List.class, Object.class));
+  }
+
+  private static boolean isSpring7OrNewer() {
+    try {
+      Class.forName("org.springframework.core.Nullness");
+      return true;
+    } catch (ClassNotFoundException e) {
+      return false;
     }
-    GET_HEADERS = methodHandle;
   }
 
   private static MethodHandle findGetHeadersMethod(MethodType methodType) {
     try {
-      return MethodHandles.lookup().findVirtual(HttpHeaders.class, "getOrDefault", methodType);
+      return MethodHandles.lookup().findVirtual(HttpHeaders.class, "get", methodType);
     } catch (Throwable t) {
-      return null;
+      throw new IllegalStateException(t);
     }
   }
 
@@ -60,14 +64,15 @@ public String getHttpRequestMethod(ClientRequest request) {
   @Override
   @SuppressWarnings("unchecked") // casting MethodHandle.invoke result
   public List<String> getHttpRequestHeader(ClientRequest request, String name) {
-    if (GET_HEADERS != null) {
-      try {
-        return (List<String>) GET_HEADERS.invoke(request.headers(), name, emptyList());
-      } catch (Throwable t) {
-        // ignore
+    try {
+      List<String> result = (List<String>) GET_HEADERS.invoke(request.headers(), name);
+      if (result == null) {
+        return emptyList();
       }
+      return result;
+    } catch (Throwable t) {
+      throw new IllegalStateException(t);
     }
-    return emptyList();
   }
 
   @Override