Why inherit the abstract class HttpServlet without overriding any methods without compilation errors?

isn"t inheriting abstract classes a necessary abstract method in an implementation?

an abstract subclass must implement all abstract methods in the abstract class, otherwise the subclass is also an abstract class.
Mar.31,2021

because it has no abstract methods! Abstract classes do not have to contain abstract methods.

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-64f5-1b36f55-2b7d1.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b36f55-2b7d1.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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