StringIndexOutOfBoundsException error while convering char to string

Question

I am getting the following error could someone please help. thanks.
java.lang.StringIndexOutOfBoundsException: String index out of range: 0
the error is on line : char a = middleinitial.trim().charAt(0);
following is my code:
if (!fname.equals("") && (!lname.equals("") && (!mi.equals(""))))
             s = lname.trim()+fname.trim()+mi.trim();
             lastName = st.nextToken().trim();
             firstName = st.nextToken().trim();
             middleinitial = st.nextToken().trim();
             char a =  middleinitial.trim().charAt(0);
             if (mi.equalsIgnoreCase(String.valueOf(a)))
               {name3 = lastName+firstName+mi;
                 if (name3.equalsIgnoreCase(s))
                   row.addElement(lastName);
                   row.addElement(firstName);
                   row.addElement(middleinitial);
                   while (st.hasMoreTokens())
                     row.addElement(st.nextToken());
                   dataVector.addElement(row);
             }

Answer 1

if i am trying to serch midname z i still get
exception because it hits null before it hits zYou should place the search inside the empty String
if() block like this:
  while ( (record = dis.readLine()) != null)        
      StringTokenizer st = new StringTokenizer(record, ":", false);
      Vector row = new Vector();
      String s;
      String t;
      if (!fname.equals("") && (!lname.equals("") && (!mi.equals(""))))          
          s = lname.trim()+fname.trim()+mi.trim();
          lastName = st.nextToken().trim();
          firstName = st.nextToken().trim();
          middleinitial = st.nextToken().trim();
          if(!middleinitial.equals("")
            char a =  middleinitial.trim().charAt(0);
            if (mi.equalsIgnoreCase(String.valueOf(a)))              
                name3 = lastName+firstName+mi;
                if (name3.equalsIgnoreCase(s))                
                    row.addElement(lastName);
                    row.addElement(firstName);
                    row.addElement(middleinitial);
                    while (st.hasMoreTokens())                  
                        row.addElement(st.nextToken());
                    dataVector.addElement(row);                       }
  }Is this how you tried it?
Alpha75