使用IDE為 Eclipse 當專案有引入JDK時，java.lang物件仍然無法引入專案中 ![1708418796349](https://hackmd.io/_uploads/BJnJraU2a.jpg) 解決方式是重新引入JRE 1. Right-click on project » Properties » Java Build Path 2. Select Libraries tab 3. Find the JRE System Library and remove it 4. Click Add Library... button at right side » Add the JRE System Library (Workspace default JRE) 根據網路上的資料來看這個錯誤的發生原因是Eclipse的bug引起的 參考 https://stackoverflow.com/questions/18075343/java-project-in-eclipse-the-type-java-lang-object-cannot-be-resolved-it-is-ind