database - Having great difficulty implementing login system using SQLite in Java -

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private void jbutton1actionperformed(java.awt.event.actionevent evt) {                                              string query;     boolean login = false;     string username = jtextfield1.gettext();     string password = jtextfield2.gettext();     try{     query = "select (cusername , cpassword) customer cusername = '"+username+"' , cpassword = '"+password+"'";     pst = conn.preparestatement(query);     pst.setstring(1, username);     pst.setstring(2, password);     pst.executequery();      string usercheck = rs.getstring(1);     string passcheck = rs.getstring(2);      if((usercheck.equals(username)) && (passcheck.equals(password)))     {         login = true;         system.out.println("it works?!");     }     else     {         login = false;         system.out.println("psyche, that's wrong number!");     }      }     catch(exception e){         system.out.println(e);     }      system.exit(0);  }

i'm having difficulty implementing login system in code. i'm trying retrieve text username , password jtextfields , query them database it's not working. @ moment i'm getting 

java.lang.arrayindexoutofboundsexception: 0

and unfortunately have no idea why. appreciated.

your query , logic behind got lot of work do:

first of all, if want parametrised query, must use '?' instead of value. pst.setstring work.

secondly, must affect pst.executequery(); resultset

query = "select cusername, cpassword customer cusername = ? , cpassword = ?"; pst = conn.preparestatement(query); pst.setstring(1, username); pst.setstring(2, password); resultset rs = pst.executequery();  if (rs.next()) {       string usercheck = rs.getstring(1);    string passcheck = rs.getstring(2); }

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