1. A computer-implemented method for deploying an application in a resource constrained environment, the application comprising a computer program written in the Java® computer programming language, the method comprising: identifying a resource constraint of a target system including identifying a target system having limited processing capacity; filtering the application in dependence upon the identified resource constraint including: preprocessing a tag library of the application, including identifying a tag library descriptor of the application and copying a listener from the tag library descriptor to a deployment descriptor for the application; identifying a hierarchy of classes of the application stored in a single file; storing each class of the hierarchy as a separate file accessible to the application; and identifying to a runtime platform the copying of the listener from the tag library descriptor to the deployment descriptor, including setting a flag in the application.