Request processing failed

Sabem me dizer o que está acontecendo? Estou fazendo na plataforma STS ao invés do Eclipse, segue:

TOPICOCONTROLLER :

package br.com.alura.forum.controller;

import java.awt.List; import java.util.Arrays; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; import br.com.alura.forum.modelo.Curso; import br.com.alura.forum.modelo.Topico;

@Controllerpublic class TopicoController {

@RequestMapping("/topicos")
@ResponseBody
public List lista () {
    Topico topico = new Topico("TITULO", "MENSAGEM", new Curso("Spring", "Programacao"));

    return (List) Arrays.asList(topico,topico,topico);
}

}

ERROR:

2020-07-11 01:27:15.805 ERROR 12139 --- [nio-8080-exec-3] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.ClassCastException: java.util.Arrays$ArrayList cannot be cast to java.awt.List] with root cause