Cannot resolve symbol ‘String‘或Cannot resolve symbol ‘System‘ ——IDEA

IDEA中运行报错，“Cannot resolve symbol ‘String‘”解决方案

‘System‘解决

参考一：(31条消息) IDEA2021 提示“Cannot resolve symbol ‘String‘”解决方案_idea无法解析符号string_YT20233的博客-优快云博客https://blog.youkuaiyun.com/CNMBZY/article/details/123671368?ops_request_misc=&request_id=&biz_id=102&utm_term=cannot%20resolve%20symbol%20string&utm_medium=distribute.pc_search_result.none-task-blog-2~all~sobaiduweb~default-2-123671368.142^v73^insert_down4,201^v4^add_ask,239^v2^insert_chatgpt&spm=1018.2226.3001.4187

参考二：没有指定具体的JDK路径，File –> Project Structure–>Project SDK

(31条消息) idea 出现 Cannot resolve symbol string 的问题_icecoola_的博客-优快云博客https://blog.youkuaiyun.com/icecoola_/article/details/78235316?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522167810862016800182141707%2522%252C%2522scm%2522%253A%252220140713.130102334.pc%255Fall.%2522%257D&request_id=167810862016800182141707&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~all~first_rank_ecpm_v1~rank_v31_ecpm-4-78235316-null-null.142^v73^insert_down4,201^v4^add_ask,239^v2^insert_chatgpt&utm_term=cannot%20resolve%20symbol%20string&spm=1018.2226.3001.4187 参考三：

(31条消息) IDEA Cannot resolve symbol ‘String‘ 的解决方法_Alijuan_的博客-优快云博客https://blog.youkuaiyun.com/pipi_S/article/details/128806380?ops_request_misc=&request_id=&biz_id=102&utm_term=cannot%20resolve%20symbol%20string&utm_medium=distribute.pc_search_result.none-task-blog-2~all~sobaiduweb~default-1-128806380.142^v73^insert_down4,201^v4^add_ask,239^v2^insert_chatgpt&spm=1018.2226.3001.4187参考四：

(31条消息) [IDEA]Cannot resolve symbol ‘String‘ Cannot resolve symbol ‘System‘解决_idea中cannot resolve system_想要一天超神的博客-优快云博客https://blog.youkuaiyun.com/qq_45059376/article/details/122508057?ops_request_misc=&request_id=&biz_id=102&utm_term=cannot%20resolve%20symbol%20system&utm_medium=distribute.pc_search_result.none-task-blog-2~all~sobaiduweb~default-2-122508057.nonecase&spm=1018.2226.3001.4187