Error sql with Spring

I use async jersey web services with spring and tomcat.

All works but if tomcat run and for example 40 minute i'm not call any api, when i try to call one api i have this error:

 (XmlBeanDefinitionReader.java:317) - Loading XML bean definitions from class path resource [org/springframework/jdbc/support/sql-error-codes.xml]
 (SQLErrorCodesFactory.java:126) - SQLErrorCodes loaded: [DB2, Derby, H2, HSQL, Informix, MS-SQL, MySQL, Oracle, PostgreSQL, Sybase, Hana]

Why if i call api everything works but if i wait for example 40 min. i have this error?