${empty st}<br>
${empty ""}<br>
${empty array}<br>
${empty map}<br>
${empty ""}<br>
${empty array}<br>
${empty map}<br>
값이 null이면 true 리턴
<%
String st = null;
int[] array = new int[0];
Map<String,String> map = new HashMap<String,String>();
%>
[결과]