serialver [ -classpath path ] classnames... serialver [ -classpath path ] -show
serialver displays the version number of a class or classes. This version number is used for the purposes of serialization: the version number must change each time the serialization format of the class changes.
If the specified class declares a long serialVersionUID constant, the value of that field is displayed. Otherwise, a unique version number is computed by applying the Secure Hash Algorithm (SHA) to the API defined by the class. This program is primarily useful for computing an initial unique version number for a class, which is then declared as a constant in the class. The output of serialver is a line of legal Java code, suitable for pasting into a class definition.