Java 尝试将新列表对象添加到预定义列表对象时出错

我正在使用Java8开发SpringBootVersion2，当我试图在“createTopic”方法中向预定义的列表对象（即topicList）添加一个新的列表对象时，我遇到了一个错误

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TopicService.java

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错误

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2020-04-15 19:52:27.172错误15312---[nio-8080-exec-2] o、 a.c.c.c.[/].[dispatcherServlet]：的Servlet.service（） 路径为[]的上下文中的servlet[dispatcherServlet]引发异常 [请求处理失败；嵌套异常为 java.lang.UnsupportedOperationException]及其根本原因

java.lang.UnsupportedOperationException:在 add（AbstractList.java:148）~[na:1.8.0_221]at add（AbstractList.java:108）~[na:1.8.0_221]at io.javabrains.springBootStarter.Service.TopicService.createTopic（TopicService.java:29） ~[classes/:na]at io.javabrains.springBootStarter.controller.TopicController.createTopic（TopicController.java:31） sun.reflect.NativeMethodAccessorImpl.invoke0（本机）处的~[classes/:na] 方法）~（na:1.8.0_221）at invoke（NativeMethodAccessorImpl.java:62） ~（na:1.8.0_221）at sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43） 位于java.lang.reflect.Method.invoke（Method.java:498）的~[na:1.8.0221] ~（na:1.8.0_221）at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke（InvocableHandlerMethod.java:209） ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest（InvocableHandlerMethod.java:136） ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle（ServletInvocableHandlerMethod.java:102） ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod（RequestMappingHandlerAdapter.java:894） ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal（RequestMappingHandlerAdapter.java:800） ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle（AbstractHandlerMethodAdapter.java:87） ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.springframework.web.servlet.DispatcherServlet.doDispatch（DispatcherServlet.java:991） ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.springframework.web.servlet.DispatcherServlet.doService（DispatcherServlet.java:925） ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.springframework.web.servlet.FrameworkServlet.processRequest（FrameworkServlet.java:981） ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.springframework.web.servlet.FrameworkServlet.doPost（FrameworkServlet.java:884） ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]at javaservlet.http.HttpServlet.service（HttpServlet.java:661） ~[tomcat-embed-core-8.5.39.jar:8.5.39]at org.springframework.web.servlet.FrameworkServlet.service（FrameworkServlet.java:858） ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]at javaservlet.http.HttpServlet.service（HttpServlet.java:742） ~[tomcat-embed-core-8.5.39.jar:8.5.39]at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:231） ~[tomcat-embed-core-8.5.39.jar:8.5.39]at org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:166） ~[tomcat-embed-core-8.5.39.jar:8.5.39]at org.apache.tomcat.websocket.server.WsFilter.doFilter（WsFilter.java:52） ~[tomcat-embed-websocket-8.5.39.jar:8.5.39]at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:193） ~[tomcat-embed-core-8.5.39.jar:8.5.39]at org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:166） ~[tomcat-embed-core-8.5.39.jar:8.5.39]at org.springframework.web.filter.RequestContextFilter.doFilterInternal（RequestContextFilter.java:99） ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.springframework.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107） ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:193） ~[tomcat-embed-core-8.5.39.jar:8.5.39]at org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:166） ~[tomcat-embed-core-8.5.39.jar:8.5.39]at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal（HttpPutFormContentFilter.java:109） ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.springframework.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107） ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:193） ~[tomcat-embed-core-8.5.39.jar:8.5.39]at org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:166） ~[tomcat-embed-core-8.5.39.jar:8.5.39]at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal（HiddenHttpMethodFilter.java:93） ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.springframework.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107） ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:193） ~[tomcat-embed-core-8.5.39.jar:8.5.39]at org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:166）

public class TopicService {

    private List<TopicObject>  topicList = Arrays.asList(
            new TopicObject("Java", "Java Course", "Spring boot in java"),
            new TopicObject("Maths", "Mathematics class","12th maths")
    );



    public String createTopic(TopicObject topicObj){

         topicList.add(new TopicObject("Java1", "Java Course1", "Spring boot in java1"));

        return "Request successful"  ;
    }
}

package io.javabrains.springBootStarter.controller;

import com.fasterxml.jackson.annotation.JsonProperty;

public class TopicObject {

    @JsonProperty("id")
    private String id;

    @JsonProperty("name")
    private String name;

    @JsonProperty("description")
    private String description;

    public TopicObject() {
    }

    public TopicObject(String id, String name, String description) {
        this.id = id;
        this.name = name;
        this.description = description;
    }


    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

}

private List<TopicObject>  topicList = Arrays.asList(
            new TopicObject("Java", "Java Course", "Spring boot in java"),
            new TopicObject("Maths", "Mathematics class","12th maths")
    );

private List<TopicObject>  topicList = new ArrayList<>(Arrays.asList(
        new TopicObject("Java", "Java Course", "Spring boot in java"),
        new TopicObject("Maths", "Mathematics class", "12th maths")
));