Software is too expensive to build cheaply...

The example he had was:

// Stripping trailing phone extensions for contact numbers for other group X, system XYZ... 
String newNum = "";
keepGoing = true;
for(int c=0;c
  char ch = oldNumber.charAt(c);
  if (ch >= '0' && ch <='9' && keepGoing) {
     newNum += ch;
   } else if (ch  '(' || ch  ' ' || ch  'x' || ch  'X')) {
     keepGoing = false;
   }
}

And here's how I would do it:

  String newNum = stripPhoneExtension(oldNumber);

// later in the class...

/**
 * Strip the extension from a phone number. Everything before the extension
 * will be returned.
 * @return the (stripped) phone number.
 */
private String stripPhoneExtension(String phoneNumber) {
   int phoneNumberLength = phoneNumber.length();
   char[] extensionMarkers = {'(', ' ', 'x', 'X'};
   
   for (int index = 0; index < phoneNumberLength; index++) {
      char phoneDigit = phoneNumber.charAt();
      if (isCharInArray(phoneDigit, extensionMarkers)) {
         return phoneNumber.substring(0, index);
       }
    }
   return phoneNumber;
}

/**
 * Check to see if a char is in an array. Similar to the
 * List.contains() method, but useful where performance may be
 * an issue.
 * @param searchTerm the char to look for.
 * @param charArray the array to look in.
 * @return true if the char is present in the array, otherwise false.
 */
private boolean isCharInArray(char searchTerm, char[] charArray) {
   for (int i = 0; i < charArray.length; i++) {
      if (searchTerm == charArray[i]) {
         return true;
       }
    }
   return false;
}

Actually, for private methods like these, the param and return tags are probably overkill, but for public or protected methods I would put them there.

Hopefully that clears up some misunderstandings.