Patent ID: 7979891

Claim:
A method for securing access to classes by untrusted applications, the method comprising: providing, at a computer which includes a computer readable medium and a processor, a plurality of class files, wherein internal Application Programming Interfaces (APIs) and public APIs are maintained in separate class files; providing a filtering classloader which is configured to look-up a requested class, compare the requested class to a filter list, and by default, deny access to internal class file APIs; receiving at the computer, a request from an untrusted application to access a class stored on the computer; looking up the requested class by looking-up the class using a local classloader and, returning the class if the class is found using the local classloader or, if the class is not found using the local classloader, then looking-up the class using the filtering classloader and, returning the class if the class is found using the filtering classloader; if the class is not found by using either the local classloader or the filtering classloader then returning an exception; if the class is found by the filtering classloader then looking-up the class in a filter list which includes a plurality of documented classes available to untrusted applications; and if the class is in the filter list, then permitting the untrusted application to access the class.