Oracle DataSource Doubts?

When we get a connection using datasource say oracleDatasource . Lets say during programming, some developer does not close the connection explicity.

Will that connection be returned to connection or will it be considered as connection leak?

As it is said, datasource is created, deployed, and managed separately(by appserver) from the applications that use it. There are two ways in which we can create datasource

1. From appserver admin console.(I understand that datasource can be managed by appserver here)
2. Second way is to create开发者_运维问答 datasource in your pragramme like

   Datasource ds = new OracleDataSource();

   But how will datasource be managed by appserver api in this case as we are creating it in our programme?