Throw ClassNotFoundException for missing class resource in ThrowawayClassLoader

spring-core/src/main/java/org/springframework/aot/nativex/feature/ThrowawayClassLoader.java

@@ -54,7 +54,11 @@ protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundE
 				return super.loadClass(name, true);
 			}
 			catch (ClassNotFoundException ex) {
-				return loadClassFromResource(name);
+				Class<?> loadedFromResource = loadClassFromResource(name);
+				if (loadedFromResource == null) {
+					throw ex;
+				}
+				return loadedFromResource;
 			}
 		}
 	}

spring-core/src/test/java/org/springframework/aot/nativex/feature/ThrowawayClassLoaderTests.java

@@ -25,6 +25,7 @@
 import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 
 /**
  * Tests for {@link ThrowawayClassLoader}.
@@ -56,6 +57,23 @@ public InputStream getResourceAsStream(String name) {
 		assertThat(closed).as("InputStream closed").isTrue();
 	}
 
+	@Test
+	void loadClassThrowsClassNotFoundExceptionWhenClassResourceIsMissing() {
+		// The grandparent resolves bootstrap classes only, so super.loadClass(...) fails,
+		// and the resource loader provides no class bytes. The fallback must then honor the
+		// ClassLoader.loadClass contract by reporting the failure instead of returning null.
+		ClassLoader resourceLoader = new ClassLoader(new ClassLoader(null) {}) {
+			@Override
+			public InputStream getResourceAsStream(String name) {
+				return null;
+			}
+		};
+		ThrowawayClassLoader classLoader = new ThrowawayClassLoader(resourceLoader);
+
+		assertThatExceptionOfType(ClassNotFoundException.class)
+				.isThrownBy(() -> classLoader.loadClass("com.example.MissingClass"));
+	}
+
 	private static byte[] classBytesOf(String className) throws IOException {
 		String resourceName = className.replace('.', '/') + ".class";
 		try (InputStream in = ThrowawayClassLoaderTests.class.getClassLoader().getResourceAsStream(resourceName)) {