1. A system, comprising: at least one processor; and a memory storing program instructions executable by the at least one processor to implement a dynamic class reloading component configured to: determine that a currently loaded version of a class in a running application is not current with a class definition of the class in a class file, wherein the class definition specifies a new version of the class; and in response to said determine: generate a new version of a body class for the class and a new version of a static body class for the class using bytecode from the class file, wherein the new versions of the body class and the static body class are given unique names, wherein the body class implements instance methods of the class according to the class definition of the class in the class file, and wherein the static body class implements static methods of the class according to the class definition of the class in the class file; generate an instance of the new version of the static body class and set a static body class field of the class to refer to the instance of the new version of the static body class; for each existing instance of the class, generate an instance of the new version of the body class and set a body class field of the existing instance of the class to the corresponding instance of the new version of the body class; and load the new version of the class corresponding to the class definition of the class in the class file via a class loader for the class.