Several implicit objects are available for you to use in your JSPs. These objects make it convenient to access important objects you may need to interact with in scriptlets and expressions. They include the request and response, session and application, exception, and several other useful objects. Among the ones that you will use most frequently are out and pageContext. In addition to providing a way to write to the output stream, you learned that out, an instance of JspWriter, has a number of methods used to manage buffering. You can let the system manage the buffer automatically, or you can do it yourself. The pageContext provides a single object that is used most frequently for storing and retrieving objects in any scope. It also has convenient methods to forward the current request to or include other Web resources. If it's important to know what version of container you are running in, then you can use the JspEngineInfo class to determine that.