diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/LongTaskTimer.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/LongTaskTimer.java
index <HASH>..<HASH> 100644
--- a/micrometer-core/src/main/java/io/micrometer/core/instrument/LongTaskTimer.java
+++ b/micrometer-core/src/main/java/io/micrometer/core/instrument/LongTaskTimer.java
@@ -66,6 +66,7 @@ public interface LongTaskTimer extends Meter, HistogramSupport {
      * @return The return value of {@code f}.
      * @throws Exception Any exception bubbling up from the callable.
      */
+    @Nullable
     default <T> T recordCallable(Callable<T> f) throws Exception {
         Sample sample = start();
         try {
@@ -82,6 +83,7 @@ public interface LongTaskTimer extends Meter, HistogramSupport {
      * @param <T> The return type of the {@link Supplier}.
      * @return The return value of {@code f}.
      */
+    @Nullable
     default <T> T record(Supplier<T> f) {
         Sample sample = start();
         try {
Mark supplier/callable record methods return value as nullable

This was missed originally, but the return value is nullable and should be marked as such.

Resolves gh-<I>