### Question:
Proj { public static Integer epsgCode(CoordinateReferenceSystem crs) { String name = crs.getName(); if (name != null) { String[] split = name.split(":"); if (split.length == 2 && "epsg".equalsIgnoreCase(split[0])) { return Integer.parseInt(split[1]); } } return null; }  static CoordinateReferenceSystem crs(int srid); static CoordinateReferenceSystem crs(String s); static CoordinateReferenceSystem crs(String... projdef); static CoordinateReferenceSystem crs(Geometry geom); static Geometry crs(Geometry g, CoordinateReferenceSystem crs); static Geometry crs(Geometry g, CoordinateReferenceSystem crs, boolean overwrite); static Integer epsgCode(CoordinateReferenceSystem crs); static Bounds bounds(CoordinateReferenceSystem crs); static T reproject(T g, String from, String to); static T reproject(T g, CoordinateReferenceSystem from, 
        CoordinateReferenceSystem to); static T transform(T g, CoordinateTransform tx); static T transform(T g, CoordinateTransform tx, boolean inPlace); static Bounds reproject(Envelope e, String from, String to); static Bounds reproject(Envelope e, CoordinateReferenceSystem from,
        CoordinateReferenceSystem to); static CoordinateTransform transform(CoordinateReferenceSystem from, 
        CoordinateReferenceSystem to); static String toString(CoordinateReferenceSystem crs); static CoordinateReferenceSystem fromWKT(String wkt); static String toWKT(CoordinateReferenceSystem crs, boolean format); static boolean equal(CoordinateReferenceSystem crs1, CoordinateReferenceSystem crs2); static final CoordinateReferenceSystem EPSG_4326; static final CoordinateReferenceSystem EPSG_900913; }### Answer:
@Test public void testEpsgCode() { CoordinateReferenceSystem crs = Proj.crs("EPSG:4326"); assertEquals(4326, Proj.epsgCode(crs).intValue()); }