1. A system, comprising: one or more processors; memory coupled to the one or more processors and configured to store program instructions executable by the one or more processors to implement an application server configured to support one or more application components, wherein the application server comprises: a transaction manager module configured to provide a common interface for both local and global transactions during a same execution instance of the application server, wherein the common interface comprises a common application interface to a local transaction manager within the application server and to a global transaction manager within the application server; wherein, during the same execution instance of the application server, the transaction manager module is further configured to provide runtime logic to: determine a given one of said transactions initiated by a given application component is to be managed by the local transaction manager, and determine an other one of said transactions issued by a given application component is to be managed by the global transaction manager; wherein, during the same execution instance of the application server, the one or more application components use the common application interface to initiate said transactions regardless of a transaction manager type for transactions; and wherein one or more of the local transactions initiated via the common application interface are not part of any global transaction, do not involve any communication between the application component and the global transaction manager, and are not controlled by the global transaction manager.