Hi Sateesh
1. Just do the full restart and then check the same. before start the instance check the DB instance or DB services are running or not?
2. Could you refer the SAP KBA for error message
'com.sap.engine.bootstrap.SynchronizationException: Database initialization failed! Check database properties'
1602004 - J2EE System fails with "exitcode = 66"
1656923 - Netweaver AS Java is not starting due to bootstrap related errors
1785570 - "Database connection initialization failed!" issued by JAVA applications
3. Could you share your OS / DB & SAP version detials?
BR
SS