JDK 1.1 and later.
serialver [-show] classname...
serialver displays the version number, or serialization-unique identifier, for a named class or classes. If the 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.
When the -show option is specified, serialver displays a simple graphical interface that allows the user to type in a single classname at a time and obtain its serialization UID. When using -show, no class names may be specified on the command-line.
serialver is written in Java, and so it is sensitive to the CLASSPATH environment variable in the same way that the java interpreter is. The specified classes are looked up relative to this class path.
java.io.ObjectStreamClass