diff --git a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ConcurrentTaskScheduler.java b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ConcurrentTaskScheduler.java
index 01770c2c19..c814b73821 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ConcurrentTaskScheduler.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ConcurrentTaskScheduler.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -191,6 +191,7 @@ public class ConcurrentTaskScheduler extends ConcurrentTaskExecutor implements T
 	 * @see Clock#systemDefaultZone()
 	 */
 	public void setClock(Clock clock) {
+		Assert.notNull(clock, "Clock must not be null");
 		this.clock = clock;
 	}
 
diff --git a/spring-context/src/main/java/org/springframework/scheduling/concurrent/SimpleAsyncTaskScheduler.java b/spring-context/src/main/java/org/springframework/scheduling/concurrent/SimpleAsyncTaskScheduler.java
index a4b5a0a3c7..debb853d3c 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/concurrent/SimpleAsyncTaskScheduler.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/concurrent/SimpleAsyncTaskScheduler.java
@@ -41,6 +41,7 @@ import org.springframework.scheduling.TaskScheduler;
 import org.springframework.scheduling.Trigger;
 import org.springframework.scheduling.support.DelegatingErrorHandlingRunnable;
 import org.springframework.scheduling.support.TaskUtils;
+import org.springframework.util.Assert;
 import org.springframework.util.ErrorHandler;
 
 /**
@@ -114,10 +115,10 @@ public class SimpleAsyncTaskScheduler extends SimpleAsyncTaskExecutor implements
 	/**
 	 * Set the clock to use for scheduling purposes.
 	 * <p>The default clock is the system clock for the default time zone.
-	 * @since 5.3
 	 * @see Clock#systemDefaultZone()
 	 */
 	public void setClock(Clock clock) {
+		Assert.notNull(clock, "Clock must not be null");
 		this.clock = clock;
 	}
 
diff --git a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolTaskScheduler.java b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolTaskScheduler.java
index 9ab42bae99..65b2e94872 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolTaskScheduler.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolTaskScheduler.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -159,6 +159,7 @@ public class ThreadPoolTaskScheduler extends ExecutorConfigurationSupport
 	 * @see Clock#systemDefaultZone()
 	 */
 	public void setClock(Clock clock) {
+		Assert.notNull(clock, "Clock must not be null");
 		this.clock = clock;
 	}
 
diff --git a/spring-context/src/test/java/org/springframework/scheduling/concurrent/ConcurrentTaskExecutorTests.java b/spring-context/src/test/java/org/springframework/scheduling/concurrent/ConcurrentTaskExecutorTests.java
index 4347a92b02..7b011c9eb6 100644
--- a/spring-context/src/test/java/org/springframework/scheduling/concurrent/ConcurrentTaskExecutorTests.java
+++ b/spring-context/src/test/java/org/springframework/scheduling/concurrent/ConcurrentTaskExecutorTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,8 +17,8 @@
 package org.springframework.scheduling.concurrent;
 
 import java.util.concurrent.Executor;
+import java.util.concurrent.Future;
 import java.util.concurrent.LinkedBlockingQueue;
-import java.util.concurrent.RunnableFuture;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 
@@ -52,8 +52,8 @@ class ConcurrentTaskExecutorTests extends AbstractSchedulingTaskExecutorTests {
 	@AfterEach
 	void shutdownExecutor() {
 		for (Runnable task : concurrentExecutor.shutdownNow()) {
-			if (task instanceof RunnableFuture) {
-				((RunnableFuture<?>) task).cancel(true);
+			if (task instanceof Future) {
+				((Future<?>) task).cancel(true);
 			}
 		}
 	}
diff --git a/spring-context/src/test/java/org/springframework/scheduling/concurrent/ThreadPoolTaskSchedulerTests.java b/spring-context/src/test/java/org/springframework/scheduling/concurrent/ThreadPoolTaskSchedulerTests.java
index 7226c0abd6..64a1144f7f 100644
--- a/spring-context/src/test/java/org/springframework/scheduling/concurrent/ThreadPoolTaskSchedulerTests.java
+++ b/spring-context/src/test/java/org/springframework/scheduling/concurrent/ThreadPoolTaskSchedulerTests.java
@@ -147,7 +147,7 @@ class ThreadPoolTaskSchedulerTests extends AbstractSchedulingTaskExecutorTests {
 		catch (InterruptedException ex) {
 			throw new IllegalStateException(ex);
 		}
-		assertThat(latch.getCount()).as("latch did not count down,").isEqualTo(0);
+		assertThat(latch.getCount()).as("latch did not count down").isEqualTo(0);
 	}