java - Serializable subclass of non-serializable parent class -

i hitting brickwall serialization of subclass of location in android/java

location not serializable. have first subclass called falocation not have instance variables. have declared serializable.

then have second class called waypoint looks this:

public class waypoint extends falocation implements serializable {      /**      *       */     private static final long serialversionuid = 1l;      /* class variables *******************************************************/     private static int class_version=1; //used version parcels      /* instance variables ****************************************************/     private transient string type=datahelper.pt_type_us;     private transient string country;      private transient string name=null;     private transient string description=null;     private transient int elevation = 0;     private transient int population = 0; // afterthought, added match db structure      /* constructors **********************************************************/         public waypoint() {         super();     }      public waypoint(double lat, double lon, string name, string description) {         super(lat, lon);         this.setname(name);         this.setdescription(description);     }      public waypoint(location l) {         super(l);     }      public waypoint(string provider) {         super(provider);     }       /* implementing serializable */     private void writeobject(java.io.objectoutputstream out) throws ioexception {         log.v("droidfa", "serialising \"%s\" (v%d).", waypoint.class.getsimplename(), class_version);         out.writeint(class_version);          out.writeobject(type);         out.writeobject(country);         out.writeobject(name);         out.writeobject(description);         out.writeint(elevation);         out.writeint(population);     }      private void readobject(java.io.objectinputstream in) throws ioexception, classnotfoundexception {          int serialclassversion = in.readint();         log.v("droidfa", "deserialising \"%s\" (v%d).", waypoint.class.getsimplename(),serialclassversion);          type = (string) in.readobject();         country = (string) in.readobject();         name = (string) in.readobject();         description = (string) in.readobject();         elevation = in.readint();         population = in.readint();     } } 

serialization works fine.

deseriamization produces followwing exception (the leg object contains waypoint).:

10-05 13:50:35.259: warn/system.err(7867): java.io.invalidclassexception: android.location.location; illegalaccessexception 10-05 13:50:35.267: warn/system.err(7867):     @ java.io.objectinputstream.resolveconstructorclass(objectinputstream.java:2010) 10-05 13:50:35.267: warn/system.err(7867):     @ java.io.objectinputstream.readnewobject(objectinputstream.java:2095) 10-05 13:50:35.267: warn/system.err(7867):     @ java.io.objectinputstream.readnonprimitivecontent(objectinputstream.java:929) 10-05 13:50:35.267: warn/system.err(7867):     @ java.io.objectinputstream.readobject(objectinputstream.java:2285) 10-05 13:50:35.278: warn/system.err(7867):     @ java.io.objectinputstream.readobject(objectinputstream.java:2240) 10-05 13:50:35.278: warn/system.err(7867):     @ com.droidfa.navigation.leg.readobject(leg.java:262) .../... 

is absolutely necessary serialize location? maybe mark transient, , obtain dynamically after deserializing object. (anyway, documentation ) :

q: if class not implement serializable subclass b implements serializable, fields of class serialized when b serialized?

a: fields of serializable objects written out , restored. object may restored if has no-arg constructor initialize fields of non-serializable supertypes. if subclass has access state of superclass can implement writeobject , readobject save , restore state.

so, if subclass has access fields of non-serializable superclass(es) can use writeobject , readobject protocol implement serialization. otherwise, there fields won't possible serialize.