namespace aliases: no, say yes.
Support Java's package/class filename convention: yes.
Comments: yes.
?? C# Doc comments -> JavaDoc: no(t yet)
C# annotations: no(t yet)
C# modifiers -> Java modifiers: yes (not all have an exact translation, e.g. internal)
Cosmetic: support single statements as blocks.
ref / out params: yes.
fix java reserved words:  yes (check for completeness)
map built in types: yes (but, unsigned ....)
partial classes: yes.
extern aliases: no (emit warning)
overloaded generic type classes: no(t yet)
nested types: yes (C# nested types map to static java nested types)
'base' calls: yes
parenthesis: yes CS2J will automatically add parenthesis only where required.  A command line option will, additionally, retain superfluous parenthesis that are in the C# source.
dimension separators
delegates: yes.
preprocessor: yes.
is: yes.
as: yes. (expr is repeated)
null coalescing expression exp ?? default: yes (expr is repeated)
Main method: yes
ToString, GetHashCode, Equals: yes
Properties: yes (generate setter / getter methods as needed, translate usages of properties to calls to getters/setters)
events: yes. fields with delegate objects as type
enums: yes (enums as constants)
generic type argument variance annotation: no 
type parameter constraints: yes
variable number of params: yes
struct: yes (rewrites to java class, semantic change) add default constructor, call on declaration of variables with struct type
indexers: yes (generate indexer methods in Java)
operators: no(t yet) say yes
conversion operators: yes (implicit conversion isn't supported there must be a cast expression)
constructor initializers: yes (converted to this / base calls)
destructor: yes (finalizer method)
fixed: no
unsafe: no
labeled statement: partial (but, what?)
var: partial
dynamic: no
foreach: yes
throw expression without expression: yes
catch withough variable: yes
using statement: yes
checked/unchecked statement: no
LINQ: no
yield: no
literal numbers: yes
verbatim string: yes