2 Replies Latest reply on May 4, 2019 11:31 PM by 3674320

    java rookie needs help compiling source code

    3674320

      I am relatively new to Java programming and I have hit a snag I can't seem to fix.

       

      my system is 64 bit windows 10.

       

      I have this rather large bit of java code running under Tomcat 9 which does a lot of mysql database work and now I would like to get a very small part of that code running from the windows 10 command line.

      I have a number of small java test programs that compile and run from the command line with no issues.

      I first created a small test program which wou7ld just load the database driver and that was successfull.

       

      I used the following command to compile my java code

      java -cp C:\Tomcat_9_0_14\lib\mysql-connector-java-5.1.47-bin.jar;. sql2.java

       

      However when I added code to read a database table I now can't even compile the4 java source code. I receive the following error message

      Error: Could not find or load main class sql2.java

       

      Here is the sql2.java file

       

      import java.util.*;

      import java.io.*;

      import java.sql.*;

       

      public class sql2 {

          private static String mysql_username = "my_user";

          private static String mysql_user_password = "my_pass";

          private static String url = "jdbc:mysql://localhost/my_database";

          private static String db_error_message = new String();

          private class division_class {

              public int        division_id;

              public String    division_name;

              public int        conference_id;

          } // end of division_class

          private static Vector division_entries = new Vector();

          private static division_class division_node;

       

          public static void main (String args[])  {

              Connection conn;

              Statement stmt;

              ResultSet results;

              int    num_div;

              String query = new String();

       

              try {

                  Class.forName("com.mysql.jdbc.Driver").newInstance();

              } catch (Exception e) {

                  db_error_message = "Can't get MySQL Instance : " + e;

                  System.out.println(db_error_message + "\n");

                  System.exit(1);

              } // CATCH

              System.out.println("Successfully loaded database driver\n");

       

              try {

                  conn = DriverManager.getConnection(url,mysql_username,mysql_user_password);

                  stmt = conn.createStatement();

                  results = stmt.executeQuery("SELECT * FROM hockey_divisions");

                  num_div = 0;

                  while (results.next()) {

                      num_div += 1;

                      division_node = new division_class();

                      division_node.division_id = results.getInt(1);

                      division_node.division_name = results.getString(2);

                      division_node.conference_id = results.getInt(3);

                      division_entries.addElement(division_node);

                  } // WHILE displaying SELECT results

              } catch (Exception e) {

                  db_error_message = "Database error : " + e;

                  System.out.println(db_error_message + "\n");

                  System.exit(1);

              } // CATCH

       

          System.exit(0);

          } // end of main

      } // end of sql2

       

      As you can see, there is a "main" class. What have I done that is so horribly wrong ?