I have Eclipse 3.1.1 and MyEclipse 4.0.3 GA and the JSP validator seems to not know about any JDK 1.4 functions. For example, it will flag the use of java.lang.String.replaceAll as an unknown method, even though the code complete in the JSP editor will list that method! If I try to use something like replaceAll in a .java file it is not flagged, only in jsps.