SQL Error: 0, SQLState: 08S01 Communications link failure

I am getting this error (not so frequently):

2013-05-08 16:44:35,786  WARN (JDBCExceptionReporter.java:100) [org.hibernate.util.JDBCExceptionReporter, logExceptions] - SQL Error: 0, SQLState: 08S01
2013-05-08 16:44:35,786 ERROR (JDBCExceptionReporter.java:101) [org.hibernate.util.JDBCExceptionReporter, logExceptions] - Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
2013-05-08 16:44:35,833 ERROR (AdminDaoImpl.java:297) [com.myapp.admin.db.AdminDaoImpl, createFilePackage] - data-upload: Exception while adding new file package
org.hibernate.exception.JDBCConnectionException: Cannot open connection
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:97) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:52) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:449) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:142) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:85) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1354) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at com.myapp.admin.db.AdminDaoImpl. createFilePackage(AdminDaoImpl.java:182) [AdminDaoImpl.class:na]
    at com.myapp.admin.ctrl.UploadController.processUploadZip(UploadController.java:217) [UploadController.class:na]
    at sun.reflect.GeneratedMethodAccessor106.invoke(Unknown Source) [na