package  jsp.custom.tag;

 public   class  C {

     private   static  C c;
    
     public  C() {}
    
     public   static  C getC() {
         if (c ==  null )
            c =  new  C();
        
         return  c;
    }
    
     public   static   final   int  intVal =  666 ;
     public   static   final  String strVal = "blah";
     public   static   final   Float  f =  new   Float ( 3 . 14 );
     public   static   final  Shit shit =  new  Shit("delicious",  93 );
  
}

 class  Shit {
     private  String shit;
     private   int  smells;
    
     public  Shit(String shit,  int  smells) {
         this .shit = shit;
         this .smells = smells;
    }
    
     public  String toString() {
         return  "SHIT>> " + shit + " " + smells + " <<SHIT";
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"
                        "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
<taglib>
 <tlib-version> 1 . 0 </tlib-version>
 <jsp-version> 1 . 2 </jsp-version>
 <short-name>shit</short-name>
 <uri>http://someshit/tags/</uri>

 <tag>
  <name>const</name>
  <tag-class>jsp.custom.tag.Const</tag-class>
  <attribute>
      <name>constName</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
   </attribute>
 </tag>
</taglib>

 package  jsp.custom.tag;

 import  java.io.IOException;

 import  javax.servlet.jsp.tagext.TagSupport;

 public   class   Const   extends  TagSupport {
    
     private  String constName;
        
     public   void  setConstName(String constName) {
         this .constName = constName;
    }
     public   int  doStartTag() {
        
         try  {
            pageContext.getOut().write(
                    C. class 
                    .getDeclaredField(constName)
                    .get(C.getC())
                    .toString()
            );
        }  catch  (IllegalArgumentException e) {
            e.printStackTrace();
        }  catch  (SecurityException e) {
            e.printStackTrace();
        }  catch  (IllegalAccessException e) {
            e.printStackTrace();
        }  catch  (NoSuchFieldException e) {
            e.printStackTrace();
        }  catch  (IOException e) {
            e.printStackTrace();
        }
         return  (SKIP_BODY);
    }
}

<%@ taglib uri="http://someshit/tags/" prefix="shit" %>
....
....
<shit:const constName="intVal" />
<shit:const constName="strVal" />
<shit:const constName="f" />
<shit:const constName="shit" />

	<taglib>
		<taglib-uri>http://someshit/tags/</taglib-uri>
		<taglib-location>/WEB-INF/shit.tld</taglib-location>
	</taglib>

 666  blah  3 . 14  SHIT>> delicious  93  <