How does Eclipse set the source code lookup path without having to go to attach source? every time

when Ecipse encounters a class without source code, can attach source, set a location to find the source code globally?

Aug.21,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b3f3a4-2c48d.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3f3a4-2c48d.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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