I raad many times the meaning of PageContext.pushBody()? What does it mean
From javadoc pushBody public BodyContent pushBody()Return a new BodyContent object, save the current "out" JspWriter, and update the value of the "out" attribute in the page scope attribute namespace of the PageContext.
This is mainly used by custom tags buffering their content. When a custom tag uses a buffer for its content, the current output stream is being pushed so that any further output will be redirected to the buffer. The initial output stream can be used by popping it out of the stack, using popBody().