public static Class<?> findClassIfExists(String className, ClassLoader classLoader) {
        try {
            return findClass(className, classLoader);
        } catch (ClassNotFoundError e) {
            return null;
        }
    }
Look up and return a class if it exists.
Like {@link #findClass}, but doesn't throw an exception if the class doesn't exist.

@param className   The class name.
@param classLoader The class loader, or {@code null} for the boot class loader.
@return A reference to the class, or {@code null} if it doesn't exist.
android/android_framework/base/src/main/java/util/XposedHelpers.java