Checking core structure...
compile_project:10: no matches found: *.in
rm -f poof-core.jar `find . -name \*.class`
(cd src; javac -encoding UTF-8 `find . -name \*.java`)
./poof/system/User.java:8: error: cannot find symbol
public class User implements Serializable {
                             ^
  symbol: class Serializable
./poof/system/Entry.java:8: error: cannot find symbol
abstract class Entry implements Serializable {
                                ^
  symbol: class Serializable
./poof/system/Root.java:8: error: cannot find symbol
public class Root extends User implements Serializable { 
                                          ^
  symbol: class Serializable
./poof/system/File.java:8: error: cannot find symbol
public class File extends Entry implements Serializable {	
                                           ^
  symbol: class Serializable
4 errors
make: *** [all] Error 1