This is another feature request expressed to me in person at SIGCSE 2010.
It would be nice if DrJava had a feature that would analyze the structure of curly braces (and perhaps parentheses, square brackets and angle brackets) and suggest places where there is incorrect nesting.
At the very least, it should point out when the number of nested braces goes negative (e.g. "{ }}") or when the mix is incorrect (e.g. "{( }").