Custom tags to avoid placing java code inside the JSP page "scripting", so that the JSP page is able to concentrate only on the presentation logic. old "classic" where a developer has to adjust the flow, from start go to ?? , will evaluate the body or not, all done depending on the return value of overridden methods . instance of tag handler is reused, can't rely on constructor to do initialization, better to use setPageContext( ). now everything is done overriding just one method. simple tag model never reuse tag handler instances. body content: in practice content is not processed at all JspWriter out=getJspContext().getOut(); out.print(" ... "); getJSPBody.invoke(null); out.print(" ... "); Modify to process body content StringWriter writer=new StringWriter(); getJSPBody.invoke( writer ); String bodyContent=writer.toString(); .tld addresses to custom tag, so how to know about explicit "within web.xml"...
is nature,the part that we influence, starts when we decide.