NonWritableChannelException when trying to update an Access database

Question

Using UCanAccess for the first time for a project and I am having a lot of trouble inserting a row into one of my database tables (in Microsoft Access).

My code makes sense but once I execute I end up getting the same error every time, even though NetBeans is able to connect to my database.

 
    package Vegan;


import java.sql.Connection;
import java.sql.DriverManager;


public class connectionString {

static Connection connection = null;

public static Connection getConnection()
{
    try
    {
        connection = DriverManager.getConnection("jdbc:ucanaccess://C://MyDatabase1.accdb");
        System.out.println("---connection succesful---");
    }

    catch (Exception ex)
    {
        System.out.println("Connection Unsuccesful");
    }

    return connection;
}  

    package Vegan;


import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;


public class DB {


private static ResultSet rs = null;
private static PreparedStatement ps = null;
private static Connection connection = null;

public DB() {
    connection = connectionString.getConnection();
}


public void AddTest() {
    try {

        String sql = "INSERT INTO CategoryTbl(CategoryName) VALUES (?)";
        ps = connection.prepareStatement(sql);

        ps.setString(1, "Flours");
        ps.executeUpdate();
        System.out.println("Inserted");
    } catch (Exception ex) {
        System.out.println(ex.getLocalizedMessage().toString());
    }


}

After that, when I execute the the AddTest() method, I get this system output:

     run:
    ---connection succesful---
    java.nio.channels.NonWritableChannelException
    at sun.nio.ch.FileChannelImpl.write(FileChannelImpl.java:724)
    at com.healthmarketscience.jackcess.impl.PageChannel.writePage(PageChannel.java:297)
    UCAExc:::3.0.6 null
    at com.healthmarketscience.jackcess.impl.PageChannel.writePage(PageChannel.java:234)
    at com.healthmarketscience.jackcess.impl.TableImpl.writeDataPage(TableImpl.java:1375)
    at com.healthmarketscience.jackcess.impl.TableImpl.addRows(TableImpl.java:1624)
    at com.healthmarketscience.jackcess.impl.TableImpl.addRow(TableImpl.java:1462)
    at net.ucanaccess.converters.UcanaccessTable.addRow(UcanaccessTable.java:44)
    at net.ucanaccess.commands.InsertCommand.insertRow(InsertCommand.java:101)
    at net.ucanaccess.commands.InsertCommand.persist(InsertCommand.java:148)
    at net.ucanaccess.jdbc.UcanaccessConnection.flushIO(UcanaccessConnection.java:315)
    at net.ucanaccess.jdbc.UcanaccessConnection.commit(UcanaccessConnection.java:205)
    at net.ucanaccess.jdbc.AbstractExecute.executeBase(AbstractExecute.java:161)
    at net.ucanaccess.jdbc.ExecuteUpdate.execute(ExecuteUpdate.java:50)
    at net.ucanaccess.jdbc.UcanaccessPreparedStatement.executeUpdate(UcanaccessPreparedStatement.java:253)
    at Vegan.DB.AddTest(DB.java:91)
    at Vegan.TestDB.main(TestDB.java:17)
BUILD SUCCESSFUL (total time: 1 second)

With no changes being made to the database when I check on it again Access. What could be causing this, and what does the error message mean? Thank you

Answer 1

"java.nio.channels.NonWritableChannelException" means that the database file cannot be updated. In your case that was because the database file was in the root folder of the Windows system drive (C:\) and mere mortals have restricted permissions on that folder.

Solution: Move the database file to a folder where you have full write access.