28. The software development platform of claim 27 , wherein said dedicated computer program is a runtime engine that automatically executes said software applications at runtime, according to the logic defined by said hierarchies of models.
27. A software development platform having a processor for overcoming the need to write computer source code in order to develop software applications, comprising: a visualizable computer executable modeling language for the definition of software applications, said definition developed by performing the steps of: defining each of said software applications in a hierarchy of process models, input and output slots, data models, and flow rules, wherein said process models, input and output slots, data models and flow rules are used for defining each of the software applications, the defining step further comprising: classifying some of said process models and said data models that must not contain any sub-process as atomic; classifying all other process models and data models that contain one or more sub processes as composite; defining each of said composite process models as a construction of one or more sub process models, said input and output slots, said data models, and said flow rules; classifying inputs sent to the input slots into mandatory and optional; defining a portion of said input slots as being one of mandatory and optional, wherein a process that requires an input at each of its mandatory input slots for its initiation does not start before all said mandatory inputs are received; defining each of said composite data models as a construction of one or more sub data models; and defining each of said flow rules by connecting a pair selected from said input and output slots, said data models, and the one or more sub data models, wherein said flow rules define both data flow and process flow in the process and data models; a visual modeling tool for defining said software applications by at least one user as said hierarchies of models in said modeling language; and a dedicated computer program to automatically execute said software applications without requiring further coding according to the logic defined by said hierarchies of models, wherein said process models, data models, input and output slots, and flow rules are arranged in a structural hierarchy conforming to a set of rigid composition rules.