1，File
2，Preferences
3，General----Existing----next
4. Browse to select the project to import ---finash
5. Many errors may appear after importing
Check whether the jdk environment of the project is the same as the current environment
When not the same, you need to replace the jdk library
Select the project name --- right click ---build Path---configure Build path
Select JRE-->remove under Liberiaries
6,Add Library--->JRE System Library-->next
7. Select the default JRE --- finish
8. If there is a "red cross" in Source, project, and Libraries
There are empty references in the description,
For unused references, "select ----remove "
Remove null references for usefulness, re-import
