If you are trying to compile from command prompt of window OS, then
set path="jdk/bin directory";%path%
set classpath="struts jar file name with path";%classpath%
set classpath="servlet jar file name with path";%classpath%
javac -d . *.java
Are you using your Eclipse or MyEclipse? The Action classes you want to compile are those that you wrote? Normally IDE's can automatically compile your code, so, if you want to compile your code, most probably it is already done by the IDE (look into your workspace on your file system), and when you deploy your app into a server the IDE will just move the compiled code to the AS.
Maybe this kind of question is for the IDE's forum. Please let us know if this information is enough or you have more doubts about struts.