The type XXX cannot be resolved. It is indirectly

在Eclipse中遇到The type XXX cannot be resolved. It is indirectly referenced from required .class files錯誤.....,查找的解決辦法以下:

一: 
It is indirectly referenced from required .class file

緣由：你正要使用的類調用了另外一個類，而這個類又調用了其餘類，這種關係可能會有好多層。而在這個調用的過程當中，某個類所在的包的缺失就會形成以上那個錯誤。

解決方法：導入缺失的包

二:
The project was not built since its build path is incomplete. Cannot find the class file for java.lang.Object. Fix the build path then try building this project 
The type java.lang.Object cannot be resolved. It is indirectly referenced from required .class files

出現以上訊息的緣由是因為你裝了多個版本的jre或jdk的關係。本來Eclipse在創建專案時，會自動參照你的jre路徑，但多個版本就沒辦法了。 
你只能手動創建… 
1. 進入window\preferences\java\Installed JREs 
1)按Add 
2)輸入JRE Name, 例JDK1.5.0.03 
3)JRE home directory, 選擇安裝的路徑 
4)按OK 
2. 進入Project\properties\Java Bulid Path 
1)Add library 
2)選JRE System Library後按Next 
3)選workplace default JRE後按finish...