1. A method of executing a virtualized application able to run in a virtualized environment, the method comprising: using a computer to perform the method of: searching for a license pre-stored in the virtualized application, upon an occurrence of an event to launch the virtualized application; monitoring a system environment, receiving a license from the system environment, and determining whether the license received from the system environment conforms with the pre-stored license by comparing the license received from the system environment with the license pre-stored in the virtualized application; and launching the virtualized application to run in the virtualized environment, according to an execution policy of the virtualized application, upon determining that the license received from the system environment conforms with the pre-stored license, wherein the determining of whether the license received from the system environment conforms with the pre-stored license is performed by an environment monitor included in the virtualized application in the virtualized environment.