diff --git a/hal/src/main/native/cpp/jni/CANJNI.cpp b/hal/src/main/native/cpp/jni/CANJNI.cpp
index 968f656634..d69786ed63 100644
--- a/hal/src/main/native/cpp/jni/CANJNI.cpp
+++ b/hal/src/main/native/cpp/jni/CANJNI.cpp
@@ -62,9 +62,7 @@ Java_edu_wpi_first_hal_can_CANJNI_FRCNetCommCANSessionMuxReceiveMessage
   if (!CheckCANStatus(env, status, *messageIDPtr)) {
     return nullptr;
   }
-  return MakeJByteArray(env,
-                        std::string_view{reinterpret_cast<const char*>(buffer),
-                                         static_cast<size_t>(dataSize)});
+  return MakeJByteArray(env, {buffer, static_cast<size_t>(dataSize)});
 }
 
 /*
diff --git a/hal/src/main/native/cpp/jni/simulation/BufferCallbackStore.cpp b/hal/src/main/native/cpp/jni/simulation/BufferCallbackStore.cpp
index 265b363e17..1b6ec94b55 100644
--- a/hal/src/main/native/cpp/jni/simulation/BufferCallbackStore.cpp
+++ b/hal/src/main/native/cpp/jni/simulation/BufferCallbackStore.cpp
@@ -57,9 +57,8 @@ void BufferCallbackStore::performCallback(const char* name, uint8_t* buffer,
     std::fflush(stdout);
   }
 
-  auto toCallbackArr = MakeJByteArray(
-      env, std::string_view{reinterpret_cast<const char*>(buffer),
-                            static_cast<size_t>(length)});
+  auto toCallbackArr =
+      MakeJByteArray(env, {buffer, static_cast<size_t>(length)});
 
   env->CallVoidMethod(m_call, sim::GetBufferCallback(), MakeJString(env, name),
                       toCallbackArr, static_cast<jint>(length));
diff --git a/hal/src/main/native/cpp/jni/simulation/ConstBufferCallbackStore.cpp b/hal/src/main/native/cpp/jni/simulation/ConstBufferCallbackStore.cpp
index cba0a5b196..2cd652f59a 100644
--- a/hal/src/main/native/cpp/jni/simulation/ConstBufferCallbackStore.cpp
+++ b/hal/src/main/native/cpp/jni/simulation/ConstBufferCallbackStore.cpp
@@ -58,9 +58,8 @@ void ConstBufferCallbackStore::performCallback(const char* name,
     std::fflush(stdout);
   }
 
-  auto toCallbackArr = MakeJByteArray(
-      env, std::string_view{reinterpret_cast<const char*>(buffer),
-                            static_cast<size_t>(length)});
+  auto toCallbackArr =
+      MakeJByteArray(env, {buffer, static_cast<size_t>(length)});
 
   env->CallVoidMethod(m_call, sim::GetConstBufferCallback(),
                       MakeJString(env, name), toCallbackArr,
diff --git a/ntcore/src/main/native/cpp/jni/NetworkTablesJNI.cpp b/ntcore/src/main/native/cpp/jni/NetworkTablesJNI.cpp
index 5cdf39177c..b83c0c3e1d 100644
--- a/ntcore/src/main/native/cpp/jni/NetworkTablesJNI.cpp
+++ b/ntcore/src/main/native/cpp/jni/NetworkTablesJNI.cpp
@@ -198,16 +198,22 @@ static jobject MakeJObject(JNIEnv* env, const nt::Value& value) {
                             static_cast<jdouble>(value.GetDouble()));
     case NT_STRING:
       return MakeJString(env, value.GetString());
-    case NT_RAW:
-      return MakeJByteArray(env, value.GetRaw());
+    case NT_RAW: {
+      auto data = value.GetRaw();
+      return MakeJByteArray(
+          env, {reinterpret_cast<const uint8_t*>(data.data()), data.size()});
+    }
     case NT_BOOLEAN_ARRAY:
       return MakeJBooleanArray(env, value.GetBooleanArray());
     case NT_DOUBLE_ARRAY:
       return MakeJDoubleArray(env, value.GetDoubleArray());
     case NT_STRING_ARRAY:
       return MakeJStringArray(env, value.GetStringArray());
-    case NT_RPC:
-      return MakeJByteArray(env, value.GetRpc());
+    case NT_RPC: {
+      auto data = value.GetRpc();
+      return MakeJByteArray(
+          env, {reinterpret_cast<const uint8_t*>(data.data()), data.size()});
+    }
     default:
       return nullptr;
   }
@@ -300,7 +306,10 @@ static jobject MakeJObject(JNIEnv* env, jobject inst,
                        "NetworkTableInstance;IILjava/lang/String;[B"
                        "Ledu/wpi/first/networktables/ConnectionInfo;)V");
   JLocal<jstring> name{env, MakeJString(env, answer.name)};
-  JLocal<jbyteArray> params{env, MakeJByteArray(env, answer.params)};
+  JLocal<jbyteArray> params{
+      env, MakeJByteArray(
+               env, {reinterpret_cast<const uint8_t*>(answer.params.data()),
+                     answer.params.size()})};
   JLocal<jobject> conn{env, MakeJObject(env, answer.conn)};
   return env->NewObject(
       rpcAnswerCls, constructor, inst, static_cast<jint>(answer.entry),
@@ -736,7 +745,9 @@ Java_edu_wpi_first_networktables_NetworkTablesJNI_getRaw
   if (!val || !val->IsRaw()) {
     return defaultValue;
   }
-  return MakeJByteArray(env, val->GetRaw());
+  auto data = val->GetRaw();
+  return MakeJByteArray(
+      env, {reinterpret_cast<const uint8_t*>(data.data()), data.size()});
 }
 
 /*
@@ -1359,7 +1370,8 @@ Java_edu_wpi_first_networktables_NetworkTablesJNI_getRpcResult__II
   if (!nt::GetRpcResult(entry, call, &result)) {
     return nullptr;
   }
-  return MakeJByteArray(env, result);
+  return MakeJByteArray(
+      env, {reinterpret_cast<const uint8_t*>(result.data()), result.size()});
 }
 
 /*
@@ -1376,7 +1388,8 @@ Java_edu_wpi_first_networktables_NetworkTablesJNI_getRpcResult__IID
   if (!nt::GetRpcResult(entry, call, &result, timeout, &timed_out)) {
     return nullptr;
   }
-  return MakeJByteArray(env, result);
+  return MakeJByteArray(
+      env, {reinterpret_cast<const uint8_t*>(result.data()), result.size()});
 }
 
 /*
@@ -1404,7 +1417,9 @@ Java_edu_wpi_first_networktables_NetworkTablesJNI_getRpc
   if (!val || !val->IsRpc()) {
     return defaultValue;
   }
-  return MakeJByteArray(env, val->GetRpc());
+  auto data = val->GetRpc();
+  return MakeJByteArray(
+      env, {reinterpret_cast<const uint8_t*>(data.data()), data.size()});
 }
 
 /*
diff --git a/wpiutil/src/main/native/include/wpi/jni_util.h b/wpiutil/src/main/native/include/wpi/jni_util.h
index 6042f893a9..6ee2626217 100644
--- a/wpiutil/src/main/native/include/wpi/jni_util.h
+++ b/wpiutil/src/main/native/include/wpi/jni_util.h
@@ -187,7 +187,8 @@ class JArrayRefInner {
 };
 
 /**
- * Specialization of JArrayRefBase to provide std::string_view conversion.
+ * Specialization of JArrayRefBase to provide std::string_view conversion
+ * and span<const uint8_t> conversion.
  */
 template <typename C>
 class JArrayRefInner<C, jbyte> {
@@ -201,6 +202,14 @@ class JArrayRefInner<C, jbyte> {
     }
     return {reinterpret_cast<const char*>(arr.data()), arr.size()};
   }
+
+  span<const uint8_t> uarray() const {
+    auto arr = static_cast<const C*>(this)->array();
+    if (arr.empty()) {
+      return {};
+    }
+    return {reinterpret_cast<const uint8_t*>(arr.data()), arr.size()};
+  }
 };
 
 /**
@@ -484,12 +493,12 @@ inline jintArray MakeJIntArray(JNIEnv* env, const std::vector<T>& arr) {
 }
 
 /**
- * Convert a std::string_view into a jbyteArray.
+ * Convert a span into a jbyteArray.
  *
  * @param env JRE environment.
- * @param str std::string_view to convert.
+ * @param str span to convert.
  */
-inline jbyteArray MakeJByteArray(JNIEnv* env, std::string_view str) {
+inline jbyteArray MakeJByteArray(JNIEnv* env, span<const uint8_t> str) {
   jbyteArray jarr = env->NewByteArray(str.size());
   if (!jarr) {
     return nullptr;