JavaDB Installation

[PhilArmstrong]

Hi,
I was following this guide (Apache Derby Tutorial) and have followed every set of it up until step 3 where I tried to compile the SimpleApp program that comes with the javadb.
It compiles but i get this message:

Note: SimpleApp.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

Not a major problem though, when I try to run it i get this error message:

Exception in thread "main" java.lang.NoClassDefFoundError: SimpleApp
Caused by: java.lang.ClassNotFoundException: SimpleApp
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClassInternal(Unknown Source)

This isn't the error for not having the class path set because I had that earlier, this is something different I think

If anyone can help me with this I'd be very grateful.

[Eranga]

Hi,

Welcome to our community. :)

You have used a List, Map without generics in one of you class. Did you use any?

[PhilArmstrong]

I don't know,
I just compiled and ran the program that came with the JavaDB:
I've tried to remove most of the comments...

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import java.util.ArrayList;
import java.util.Properties;

public class SimpleApp
{
    /* the default framework is embedded*/
    private String framework = "embedded";
    private String driver = "org.apache.derby.jdbc.EmbeddedDriver";
    private String protocol = "jdbc:derby:";


    public static void main(String[] args)
    {
        new SimpleApp().go(args);
        System.out.println("SimpleApp finished");
    }


    void go(String[] args)
    {
        /* parse the arguments to determine which framework is desired*/
        parseArguments(args);

        System.out.println("SimpleApp starting in " + framework + " mode");

        /* load the desired JDBC driver */
        loadDriver();


        Connection conn = null;

        ArrayList statements = new ArrayList(); // list of Statements, PreparedStatements
        PreparedStatement psInsert = null;
        PreparedStatement psUpdate = null;
        Statement s = null;
        ResultSet rs = null;
        try
        {
            Properties props = new Properties(); // connection properties
            // providing a user name and password is optional in the embedded
            // and derbyclient frameworks
            props.put("user", "user1");
            props.put("password", "user1");


            String dbName = "derbyDB"; // the name of the database


            conn = DriverManager.getConnection(protocol + dbName
                    + ";create=true", props);

            System.out.println("Connected to and created database " + dbName);

            // We want to control transactions manually. Autocommit is on by
            // default in JDBC.
            conn.setAutoCommit(false);

            /* Creating a statement object that we can use for running various
             * SQL statements commands against the database.*/
            s = conn.createStatement();
            statements.add(s);

            // We create a table...
            s.execute("create table location(num int, addr varchar(40))");
            System.out.println("Created table location");

            // and add a few rows...


            // parameter 1 is num (int), parameter 2 is addr (varchar)
            psInsert = conn.prepareStatement(
                        "insert into location values (?, ?)");
            statements.add(psInsert);

            psInsert.setInt(1, 1956);
            psInsert.setString(2, "Webster St.");
            psInsert.executeUpdate();
            System.out.println("Inserted 1956 Webster");

            psInsert.setInt(1, 1910);
            psInsert.setString(2, "Union St.");
            psInsert.executeUpdate();
            System.out.println("Inserted 1910 Union");

            // Let's update some rows as well...

            // parameter 1 and 3 are num (int), parameter 2 is addr (varchar)
            psUpdate = conn.prepareStatement(
                        "update location set num=?, addr=? where num=?");
            statements.add(psUpdate);

            psUpdate.setInt(1, 180);
            psUpdate.setString(2, "Grand Ave.");
            psUpdate.setInt(3, 1956);
            psUpdate.executeUpdate();
            System.out.println("Updated 1956 Webster to 180 Grand");

            psUpdate.setInt(1, 300);
            psUpdate.setString(2, "Lakeshore Ave.");
            psUpdate.setInt(3, 180);
            psUpdate.executeUpdate();
            System.out.println("Updated 180 Grand to 300 Lakeshore");


            /*
               We select the rows and verify the results.
             */
            rs = s.executeQuery(
                    "SELECT num, addr FROM location ORDER BY num");


            int number; // street number retreived from the database
            boolean failure = false;
            if (!rs.next())
            {
                failure = true;
                reportFailure("No rows in ResultSet");
            }

            if ((number = rs.getInt(1)) != 300)
            {
                failure = true;
                reportFailure(
                        "Wrong row returned, expected num=300, got " + number);
            }

            if (!rs.next())
            {
                failure = true;
                reportFailure("Too few rows");
            }

            if ((number = rs.getInt(1)) != 1910)
            {
                failure = true;
                reportFailure(
                        "Wrong row returned, expected num=1910, got " + number);
            }

            if (rs.next())
            {
                failure = true;
                reportFailure("Too many rows");
            }

            if (!failure) {
                System.out.println("Verified the rows");
            }

            // delete the table
            s.execute("drop table location");
            System.out.println("Dropped table location");

            /*
               We commit the transaction. Any changes will be persisted to
               the database now.
             */
            conn.commit();
            System.out.println("Committed the transaction");



            if (framework.equals("embedded"))
            {
                try
                {
                    // the shutdown=true attribute shuts down Derby
                    DriverManager.getConnection("jdbc:derby:;shutdown=true");

                    // To shut down a specific database only, but keeep the
                    // engine running (for example for connecting to other
                    // databases), specify a database in the connection URL:
                    //DriverManager.getConnection("jdbc:derby:" + dbName + ";shutdown=true");
                }
                catch (SQLException se)
                {
                    if (( (se.getErrorCode() == 50000)
                            && ("XJ015".equals(se.getSQLState()) ))) {
                        // we got the expected exception
                        System.out.println("Derby shut down normally");
                        // Note that for single database shutdown, the expected
                        // SQL state is "08006", and the error code is 45000.
                    } else {
                        // if the error code or SQLState is different, we have
                        // an unexpected exception (shutdown failed)
                        System.err.println("Derby did not shut down normally");
                        printSQLException(se);
                    }
                }
            }
        }
        catch (SQLException sqle)
        {
            printSQLException(sqle);
        } finally {
            // release all open resources to avoid unnecessary memory usage

            // ResultSet
            try {
                if (rs != null) {
                    rs.close();
                    rs = null;
                }
            } catch (SQLException sqle) {
                printSQLException(sqle);
            }

            // Statements and PreparedStatements
            int i = 0;
            while (!statements.isEmpty()) {
                // PreparedStatement extend Statement
                Statement st = (Statement)statements.remove(i);
                try {
                    if (st != null) {
                        st.close();
                        st = null;
                    }
                } catch (SQLException sqle) {
                    printSQLException(sqle);
                }
            }

            //Connection
            try {
                if (conn != null) {
                    conn.close();
                    conn = null;
                }
            } catch (SQLException sqle) {
                printSQLException(sqle);
            }
        }
    }


    private void loadDriver() {

        try {
            Class.forName(driver).newInstance();
            System.out.println("Loaded the appropriate driver");
        } catch (ClassNotFoundException cnfe) {
            System.err.println("\nUnable to load the JDBC driver " + driver);
            System.err.println("Please check your CLASSPATH.");
            cnfe.printStackTrace(System.err);
        } catch (InstantiationException ie) {
            System.err.println(
                        "\nUnable to instantiate the JDBC driver " + driver);
            ie.printStackTrace(System.err);
        } catch (IllegalAccessException iae) {
            System.err.println(
                        "\nNot allowed to access the JDBC driver " + driver);
            iae.printStackTrace(System.err);
        }
    }

    /**
     * Reports a data verification failure to System.err with the given message.
     *
     * @param message A message describing what failed.
     */
    private void reportFailure(String message) {
        System.err.println("\nData verification failed:");
        System.err.println('\t' + message);
    }

    /**
     * Prints details of an SQLException chain to <code>System.err</code>.
     * Details included are SQL State, Error code, Exception message.
     *
     * @param e the SQLException from which to print details.
     */
    public static void printSQLException(SQLException e)
    {
        // Unwraps the entire exception chain to unveil the real cause of the
        // Exception.
        while (e != null)
        {
            System.err.println("\n----- SQLException -----");
            System.err.println("  SQL State:  " + e.getSQLState());
            System.err.println("  Error Code: " + e.getErrorCode());
            System.err.println("  Message:    " + e.getMessage());
            // for stack traces, refer to derby.log or uncomment this:
            //e.printStackTrace(System.err);
            e = e.getNextException();
        }
    }


    private void parseArguments(String[] args)
    {
        if (args.length > 0) {
            if (args[0].equalsIgnoreCase("jccjdbcclient"))
            {
                framework = "jccjdbc";
                driver = "com.ibm.db2.jcc.DB2Driver";
                protocol = "jdbc:derby:net://localhost:1527/";
            }
            else if (args[0].equalsIgnoreCase("derbyclient"))
            {
                framework = "derbyclient";
                driver = "org.apache.derby.jdbc.ClientDriver";
                protocol = "jdbc:derby://localhost:1527/";
            }
        }
    }
}

[Eranga]

Oh, dear it's a bulky code. Need more time to test this. I don't have apache to test this also.

Did you know anything about List and so on?

[PhilArmstrong]

no, dont know anything about List, it just said to compile it to see if the database if it is installed properly.
As far as I know Apache isn't involved either, the tutorial gave no meantion of it...

[Eranga]

Ok, let see. First I want to go through your tutorial.

[johnemb]

PhilArmstrong:

The compile warnings are given because the code is using ArrayList without generics, and you are compiling using a compiler/library set which supports generics. This is quite common and is generally not a problem. Google the note's message text for more information.

To make the warnings go away, you can compile using the -Xlint:unchecked option, or modify the source code to use generics.

The code included with Java DB does not use generics because it is supposed to work on J2SE 1.4.2 as well as newer versions. J2SE 1.4.2 does not support generics.

Secondly, ClassNotFoundExceptions are always caused by CLASSPATH issues. For a description of how to set up and test your classpath for SimpleApp, see SimpleApp's documentation, at <installdir>/demo/programs/simple/example.html.