Refine LaunchedURLClassLoader load order

Refine the loading order of LaunchedURLClassLoader to consider the
root loader before locally bundled classes.

The prevents classes from locally bundled JARs from replacing system
classes.

Issue: #56232870

spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/LaunchedURLClassLoader.java

@@ -31,6 +31,8 @@ import org.springframework.boot.loader.jar.RandomAccessJarFile;
  */
 public class LaunchedURLClassLoader extends URLClassLoader {
 
+	private final ClassLoader rootClassLoader;
+
 	/**
 	 * Create a new {@link LaunchedURLClassLoader} instance.
 	 * @param urls the URLs from which to load classes and resources
@@ -38,6 +40,17 @@ public class LaunchedURLClassLoader extends URLClassLoader {
 	 */
 	public LaunchedURLClassLoader(URL[] urls, ClassLoader parent) {
 		super(urls, parent);
+		this.rootClassLoader = findRootClassLoader(parent);
+	}
+
+	private ClassLoader findRootClassLoader(ClassLoader classLoader) {
+		while (classLoader != null) {
+			if (classLoader.getParent() == null) {
+				return classLoader;
+			}
+			classLoader = classLoader.getParent();
+		}
+		return null;
 	}
 
 	/**
@@ -59,11 +72,24 @@ public class LaunchedURLClassLoader extends URLClassLoader {
 	}
 
 	private Class<?> doLoadClass(String name) throws ClassNotFoundException {
+
+		// 1) Try the root class loader
+		try {
+			if (this.rootClassLoader != null) {
+				return this.rootClassLoader.loadClass(name);
+			}
+		}
+		catch (Exception ex) {
+		}
+
+		// 2) Try to find locally
 		try {
 			return findClass(name);
 		}
-		catch (ClassNotFoundException e) {
+		catch (Exception ex) {
 		}
+
+		// 3) Use standard loading
 		return super.loadClass(name, false);
 	}