JSP 2.0 Expression Language - Implicit Objects

This example illustrates some of the implicit objects available in the Expression Language. The following implicit objects are available (not all illustrated here):

pageContext - the PageContext object
pageScope - a Map that maps page-scoped attribute names to their values
requestScope - a Map that maps request-scoped attribute names to their values
sessionScope - a Map that maps session-scoped attribute names to their values
applicationScope - a Map that maps application-scoped attribute names to their values
param - a Map that maps parameter names to a single String parameter value
paramValues - a Map that maps parameter names to a String[] of all values for that parameter
header - a Map that maps header names to a single String header value
headerValues - a Map that maps header names to a String[] of all values for that header
initParam - a Map that maps context initialization parameter names to their String parameter value
cookie - a Map that maps cookie names to a single Cookie object.

Change Parameter
foo =

EL Expression Result ${param.foo} bar ${param["foo"]} bar ${header["host"]} 127.0.0.1:8080 ${header["accept"]} text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8 ${header["user-agent"]} Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36

EL Expression	Result
${param.foo}	bar
${param["foo"]}	bar
${header["host"]}	127.0.0.1:8080
${header["accept"]}	text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,/;q=0.8
${header["user-agent"]}	Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36