java - Android copy error from asset -

i trying make application in android, using pre-created database. create data file , keep in asset folder, when application run, copy /data/data/package name/databases/data problem when run android 2.2 , copy correctly. when run android 2.3.3 over, doesn't copy database , not show errors. here code:

public class mainactivity extends activity {  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);      try {      despath="/data/data/" + getpackagename()+"/databases/data";     file f=new file(despath);     if(!f.exists())    {          copydb( getbasecontext().getassets().open("data"),new fileoutputstream(despath));     }      } catch (filenotfoundexception e) {         // todo auto-generated catch block         e.printstacktrace();     } catch (ioexception e) {         // todo auto-generated catch block         e.printstacktrace();     } }  @override public boolean oncreateoptionsmenu(menu menu) {     // inflate menu; adds items action bar if present.     getmenuinflater().inflate(r.menu.main, menu);     return true; }  public void copydb(inputstream inputstream, outputstream outputstream) throws ioexception {     byte[] buffer=new byte[1024];     int length;     while((length=inputstream.read(buffer))>0)     {         outputstream.write(buffer,0,length);     }     inputstream.close();     outputstream.close(); }     }