Database Construction Error

Question

I am new to Java and am having trouble figuring out why I am throwing this error when running the jar file.
My code builds the jar file without error, but when I try to run the application from the jar file, I get the error
in my code that reads, " Unable to open Database!". I'm assuming there is an error in the creation of
the database and that it is null. I have tried to reconfigure the Java db in Netbeans, but have not been
successful. Any ideas? My code is below. thanks.
public fine() {
// Prevent multiple instances...
if (!obtainLock()) {
return;
Database database = null;
try {
database = new Database(SqlEngine.DERBY);
} catch (Exception e) {
System.out.println(e);
JOptionPane.showMessageDialog(null, "Unable to open the database!", "Error", JOptionPane.ERROR_MESSAGE);
MainFrame mainFrame = new MainFrame(database);
mainFrame.show();
}

Answer 1

Sorry Abillconsl here is that code.
public class Database {
/** Create a local connection to a database engine.
* @param sqlEngine is the database engine type.
* @throws ClassNotFoundException if there is an error loading the driver.
* @throws SQLException if there is an error connecting to the database.
public Database(SqlEngine sqlEngine) throws ClassNotFoundException, SQLException {
this.sqlEngine = sqlEngine;
try {
Class.forName(sqlEngine.getDriverName());
} catch (Exception e) {
throw new ClassNotFoundException(e.getMessage());
con = DriverManager.getConnection(sqlEngine.getLocalUrl());
/** Create a connection to a database engine.
* @param sqlEngine is the database engine type.
* @param url is the URL to connect to.
* @throws ClassNotFoundException if there is an error loading the driver.
* @throws SQLException if there is an error connecting to the database.
public Database(SqlEngine sqlEngine, String url) throws ClassNotFoundException, SQLException {
this.sqlEngine = sqlEngine;
try {
Class.forName(sqlEngine.getDriverName());
} catch (Exception e) {
throw new ClassNotFoundException(e.getMessage());
con = DriverManager.getConnection(url);
/** Close the database connection.
* @throws SQLException if there is an error connecting to the database.
public void close() throws SQLException {
con.close();
con = null;
/** Encode a SQL qury string.
* @param s is the string to encode.
* @return the encoded string.
public static String escape(String s) {
if (s.indexOf("'") != -1 ) {
StringBuffer sb = new StringBuffer();
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
if (c == '\'') {
sb.append("''");
}else {
sb.append(c);
return sb.toString();
return s;
* Retrieve a field id from dbid table for a given field name
* @param fieldName of the field as defined in the database
* @return database identifier number for a field or zero if not found
public RwInteger getDBID(RwString fieldName){
ResultSet rs = null;
Statement stmt = null;
RwInteger dbid = new RwInteger(0);
try {
stmt = con.createStatement();
rs = stmt.executeQuery("SELECT DBID FROM dbid WHERE FieldName = '"+fieldName.toString()+"'");
while(rs.next()) {
dbid = new RwInteger(rs.getInt("DBID"));
} catch (SQLException e) {
System.out.println("Unable to Retreive FieldID for FieldName: " + fieldName.toString());
e.printStackTrace();
return dbid;
/** Retrieves a field name from dbid table for a given dbid.
* @param dbid the database field identifier number for the field
* @return field name as defined in the database
public String getFieldName(int dbid){
ResultSet rs = null;
Statement stmt = null;
String fieldName = ""; // field name not found.
try {
stmt = con.createStatement();
rs = stmt.executeQuery("SELECT FieldName FROM dbid WHERE DBID = " + dbid);
while(rs.next())
fieldName = rs.getString("FieldName");
} catch (SQLException e) {
System.out.println("Unable to Retrieve FieldName for DBID: " + dbid);
e.printStackTrace();
return fieldName;
/** Generate the friendly name for a particular field.
* @param rwType is the field to name.
* @return the friendly name for a specified field.
public String friendlyName(RwType rwType) {
return RecordType.forDbid(rwType.getFieldId())
+ "(" + (rwType.getSequenceNumber() + 1)
+ ":" + (rwType.getRecordId() + 1) + ")."
+ AbstractRecord.getFieldName(con, rwType.getFieldId());
// Database related variables.
public Connection con = null;
public static SqlEngine sqlEngine = null;
/** Unit test.
* @param args the command line arguments
public static void main(String[] args) {
try {
Database db = new Database(SqlEngine.DERBY);
int dbid = 1605;
String name = db.getFieldName(dbid);
RecordType recordType = RecordType.forDbid(dbid);
System.out.println("DBID " + dbid + " is field " + name + " in " + recordType);
AbstractRecord record = AbstractRecord.newInstance(recordType, db.con);
RwType rwType = record.getField(name);
System.out.println("rwType = " + rwType);
db.close();
} catch (Exception e) {
System.out.println(e);
}