[jacorb-developer] Error when compiling the stub

[keviin kevin]

In chapitre 4 , the grid demo. When I try to compile _MyServerStub.java I
get an error

 cannot find symbol
symbol  : class ServantObjectExt
location: package org.omg.CORBA.portable
                if ( _so instanceof
org.omg.CORBA.portable.ServantObjectExt)
                                                          ^
stock/_MyServerStub.java:83: cannot find symbol
symbol  : class ServantObjectExt
location: package org.omg.CORBA.portable

((org.omg.CORBA.portable.ServantObjectExt)_so).normalCompletion();
                                            ^
stock/_MyServerStub.java:88: cannot find symbol
symbol  : class ServantObjectExt
location: package org.omg.CORBA.portable
                if ( _so instanceof
org.omg.CORBA.portable.ServantObjectExt)
                                                          ^
stock/_MyServerStub.java:89: cannot find symbol
symbol  : class ServantObjectExt
location: package org.omg.CORBA.portable

((org.omg.CORBA.portable.ServantObjectExt)_so).exceptionalCompletion(re);
                                            ^
stock/_MyServerStub.java:94: cannot find symbol
symbol  : class ServantObjectExt
location: package org.omg.CORBA.portable
                if ( _so instanceof
org.omg.CORBA.portable.ServantObjectExt)
                                                          ^
stock/_MyServerStub.java:95: cannot find symbol
symbol  : class ServantObjectExt
location: package org.omg.CORBA.portable

((org.omg.CORBA.portable.ServantObjectExt)_so).exceptionalCompletion(err);
                                            ^
6 errors