you did not mention which version on struts you are using, if you are using struts1 then use saveToken() to prevent duplicate form submit, if struts2 use token interceptor.
ocjp 6 — Feeding a person with food is a great thing in this world. Feeding the same person by transferring the knowledge is far more better thing. The reason is the amount of satisfaction which we get through food is of only one minute or two. But the satisfaction which we can get through the knowledge is of life long.
could you please give the entire struts.xml.
check the order in your struts.xml like
package
result-types
interceptors
default-interceptor-ref
global-results
global-exception-mappings and then
action