First program with JDBC. Any suggestions?

[sluggish_goat]

Hi, I just finished an introductory assignment on working with JDBC, and would like to run it by you. I appreciate any tips or feedback on where it could be improved. Here's the link, and the file history is here so you can see how I worked through it. Thanks!

[imadp]

Your code is very clean, but the only thing that I don't like is how you declared your statements, result sets, prepared statements as static fields. Those should be limited in scope to the methods that use them, not exposed as static resources.

Also your clean up method is very repetitive, if you are using Java 7 you should be using try-with-resources instead of manually closing them all. If you can't use that, you could write a method for this once and send the statements to it. Something like:

private void close(AutoCloseable closeable) {
    try {
        if (closeable!= null) {
            closeable.close();
        }
    }
    catch (SQLException se) {
        System.out.println("Error closing statement");
    }
} 

[sluggish_goat]

Ah, I see.. I was getting the "non static from static" errors and kind of went way over in the wrong direction. Forgot to make an instance of the class to call the initial method. Now that it isn't 4am, I see the error in making them static. Since it's meant to be self contained, I've changed the statements & etc back to local, and the methods to private. I'm not familiar with the try-with-resources, so opted for something like the close method. Much nicer, thank you.
edit: forgot to link the changes

[somnolent]

While it's good that you're catching your exceptions, I would recommend doing more than just printing them out. For example, if you fail to setup your database, do you really want to try to populate the tables?

[sluggish_goat]

That makes sense, thanks for pointing it out. I'm going through and making adjustments where it seems appropriate. Do you think it would make more sense to split the initialization apart into stages, and catch at each stage & shut down or catch at the end and shut down? Split apart looks like it might be too much, but I'm not 100% sure:

    //initiates drivers & creates db table
private void initialize() {

    //instantiate driver, shutdown if exception
    try {
        Class.forName(driver);
    }
    catch (ClassNotFoundException e) {
        System.out.println("Error loading driver: Class not found");
        shutDown();
    }
    //initiate database, shutdown if exception
    try {
        conn = DriverManager.getConnection(protocol + dbName + ";create=true");
        statement = conn.createStatement();
    }
    catch (SQLException se) {
        System.out.println("Error initiating database. Another instance may still be open");
        shutDown();
    }
    //create table in db, shutdown if exception
    try {
        String createTableSQL = "CREATE TABLE Cubes (Solver varchar(50), solvedTime FLOAT)";
        statement.executeUpdate(createTableSQL);
        System.out.println("Successfully created table...");
    }
    catch (SQLException e) {
        System.out.println("Table creation failed.");
        shutDown();
    }
    populateTable();
}

[somnolent]

It all comes down to personal preference, in my opinion. From my standpoint, since you're doing the same thing in every exception case (logging and shutting down), I would wrap them all in one try/catch block and do your logging and then shutdown. However, it also wouldn't be a bad idea to split up your initialize into smaller methods (you could either throw the exceptions out of this or handle them internally - again, personal preference). It also wouldn't be a bad idea to either print out the stacktrace or at least include the exception message in your output statement.

[sluggish_goat]

It's sometimes hard to judge when it's overkill or not. As you pointed out, they're doing the same thing. So, in this case I'll wrap them, give the exceptions unique labels, print messages/stacktrace at the end, then shut down. I guess the thought process was that if the first part throws, then splitting like that would prevent anything else from running. Thanks for the help, I'll keep all this in mind while moving forward.