JBBC--Database failure

Hi,

 1.) When database connectivity is lost with the Weblogic Server , server goes to failed that after n no. of time .What is that parameter which determine that server will go to failed that after n no. of time .

2.) After restoring the DB Connectivity Server always remains in failed state ? Why 

3.) Any setting which will help so that after DB Connectivity loss Server changed from Failed to Running Stage ?--Except Node Manager

Thanks

Sahil Soni