How to see if JTextField is blank?

Question

I have yet another question. How do you check to see if a JTextField is blank, for example:
    int i = 0;
    String s = jtfStudentID.getText();
    String c = jtfCourseID.getText();
    if ((s != null) && (c != null)) {
      FindStudAndCour(s, c);
    else {
      if (FindSC == 1) {
        while ((i < studentVec.size()) &&
              (!s.equals((String)studentVec.elementAt(i)))) {
          i++;
        if (i == studentVec.size()) {
          jtfMessage.setText("Student ID not found.");
        else {
          String t;
          int Grade = 0, Passed = 0, NumCourComp = 0, Average = 0;
          try {
            for (int j = 0; j < markVec.size(); j++) {
              if (s.equals((String)markVec.elementAt(j))) {
                NumCourComp++;
                t = (String)markVec.elementAt(j + 2);
                Grade = Integer.valueOf(t).intValue();
                Average = Average + Grade;
                if (Grade >= 50) {
                  Passed++;
            if(NumCourComp != 0){
              Average = Average / NumCourComp;
          catch (Exception x) {
            jtfMessage.setText("Error: " + x);
          jtfLastName.setText("" + studentVec.elementAt(i + 1));
          jtfFirstName.setText("" + studentVec.elementAt(i + 2));
          jtfAddress.setText("" + studentVec.elementAt(i + 3));
          jtfCity.setText("" + studentVec.elementAt(i + 4));
          jtfProvince.setText("" + studentVec.elementAt(i + 5));
          jtfPCode.setText("" + studentVec.elementAt(i + 6));
          jtfPhone.setText("" + studentVec.elementAt(i + 7));
          jtfEMail.setText("" + studentVec.elementAt(i + 8));
          jtfNumCourComp.setText("" + NumCourComp);
          jtfStudAverGrade.setText("" + Average);
          jtfMessage.setText("Student found.");
      else {
        while ((i < courseVec.size()) &&
              (!c.equals((String)courseVec.elementAt(i)))) {
          i++;
        if (i == courseVec.size()) {
          jtfMessage.setText("Course ID not found.");
        else {
          String r;
          int Grade = 0, Passed = 0, NumCourses = 0, Average = 0;
          try {
            for (int j = 0; j < markVec.size(); j++) {
              if (c.equals((String)markVec.elementAt(j))) {
                NumCourses++;
                r = (String)markVec.elementAt(j + 1);
                Grade = Integer.valueOf(r).intValue();
                Average = Average + Grade;
                if (Grade >= 50) {
                  Passed++;
            if(NumCourses != 0){
              Average = Average / NumCourses;
          catch (Exception x) {
            jtfMessage.setText("Error: " + x);
          jtfCourseName.setText("" + courseVec.elementAt(i + 1));
          jtfCoordinator.setText("" + courseVec.elementAt(i + 2));
          jtfNumStudPassed.setText("" + Passed);
          jtfAverGradeCourse.setText("" + Average);
          jtfMessage.setText("Course found.");
    }Colin

Answer 1

Try:
if (yourTextField.getText().trim().length() == 0) {
// do something here
Good luck!