It is indirectly referenced from required .class file

這種問題是因爲你在導入別人的文件的時候確實jar包或者是jdk致使 好比個人狀況是 java.lang.enum cannot be resolved，It is indirectly referenced from required .class file 就是由於少了jdk，具體作法，右鍵項目-》buildpath-》configur build path-》library-》add library->jre system library->選一個jre或者jdk便可