private List<ClassSymbol> getTopLevelClasses(List<? extends JCCompilationUnit> units) { List<ClassSymbol> classes = List.nil(); for (JCCompilationUnit unit : units) { for (JCTree node : unit.defs) { if (node.getTag() == JCTree.CLASSDEF) { ClassSymbol sym = ((JCClassDecl) node).sym; Assert.checkNonNull(sym); classes = classes.prepend(sym); } } } return classes.reverse(); }