EL expressions

${person.dog.namename}
as for the . ,the first part must be map objects
the [] gives you more options than the .
${musicList["something"]}
eg:
String[] music={"Zero  7","Tahiti 80","BT"}
request.setAttribute("musiclist",music);
${musiclist["0"]} is  Zero 7
---
A String index is coerced to an int for arrays and Lists
ArrayList a=new ArrayList();
a.add("one");
....
request.setAttribute("arr",a);
you can use either ${arr[0]} or ${arr["0"]}
you can use${arr} ,which calls toString() function
-----
you can use nested expressions inside the brackets
${musicMap[music[0]]}