# JSP 2.0 Expression Language - Implicit Objects

This example illustrates some of the implicit objects available in the Expression Lanaguage. 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} | ${param.foo}
> ${'${'}param["foo"]} | ${param["foo"]}
> ${'${'}header["host"]} | ${header["host"]}
> ${'${'}header["accept"]} | ${header["accept"]}
> ${'${'}header["user-agent"]} | ${header["user-agent"]}

> `