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Issue connecting to Heroku PostgreSQL from local GlassFish

I am trying to get a JDBC connection pool and resource setup in a local GlassFish server to connect to a Heroku PostgreSQL instance.
I have tried it in Tomcat setup as a resource and it works ok, but in GlassFish I have had some issues.
First up I had to downgrade my version of Java 8 to 151 to stop one error I was getting. Now when I try and execute the query in my app I get:
java.net.ConnectException: Connection refused (Connection refused)
I think this is related to connections to Heroku PostgreSQL having to use SSL, but I am not sure what I need to do in GlassFish to configure that.
Does anyone have any experience doing this?

After a lot of head scratching and Googling, I finally got this working. The exception above is a red herring. It is complaining it cannot connect to a local Derby database which is the GlassFish default resource. This means the problem was actually related to not being able to find the resource I specified.
Here are the steps I needed to get the connection working in GlassFish 5:
Set JAVA_HOME to be JDK 1.8.0_151 (any newer version of 1.8 does not work) GlassFish needs to run on this version.
In your Bean class use #Resource(mappedName = "jdbc/postgresql"). This was the only way I could get it to find my jdbc/postgresql resource (#Resource(name = "jdbc/postgresql"), #Resource(name = "java:comp/env/jdbc/postgresql") and #Resource(lookup = "java:comp/env/jdbc/postgresql") did not work).
The connection Url must be like this:jdbc:postgresql://<host>:<port>/<databse>?sslmode=require (originally i had this jdbc:postgresql://<host>:<port>/<databse>?ssl=true&sslfactory=org.postgresql.ssl.NonValidatingFactory which had been working for me in other places).
So the key points are to use JDK 1.8.0_151, mappedName in the resource attribute and sslmode=require in the connection string.
Life should not be this complicated...

Error when trying to open a JDBC connection to Google Cloud Spanner

I am trying to open a JDBC connection to a Google Cloud Spanner database, but I get the following error message:
java.lang.IllegalArgumentException: A project ID is required for this
service but could not be determined from the builder or the
environment. Please set a project ID using the builder.
My JDBC URL is as follows:
jdbc:cloudspanner://localhost;Project=project-id;Instance=instance-id;Database=database-name;PvtKeyPath=path-to-key-file
If I remove the Project property from the URL, I get the following exception:
java.sql.SQLNonTransientConnectionException: [Simba]JDBC
Connection Refused: [Simba]JDBC Required Connection Key(s):
Project; [Simba]JDBC Optional Connection Key(s): Language,
Mode
So it seems that the driver does pick up my Project ID, but somehow does not accept it. I have checked and double checked that my project id does equal the project id that I created on Google, I have also tried to change the value to the project name instead of the project id, but to no avail.
Does anyone have a URL example that works?
EDIT: It appears to be related to the reference to the private key file. If I make an environment variable GOOGLE_APPLICATION_CREDENTIALS pointing to my private key file, the connection can successfully be made. If I remove this environment variable, I get the above exception.

Which version of the driver are you using? In the latest version, if you are specifying the path to the credentials file in the URL then you need not set GOOGLE_APPLICATION_CREDENTIALS.

As the JDBC Driver supplied by Google is severely limited (does not support DML and DDL statemetns), I have written my own JDBC Driver. The driver is designed to work with JPA/Hibernate-enabled applications. The driver can be found here: https://github.com/olavloite/spanner-jdbc
This driver supports the same kind of URL's as the driver supplied by Google, including the PvtKeyPath property.

Exception when connecting to Sybase using JDBC Driver

I'm new to Sybase database and trying to connect to Sybase using Java JDBC connection and sajdbc4.jar, but getting an error:
java.sql.SQLException: [Sybase][JDBC Driver][SQL Anywhere]Database server not found
Here is my connection string:
jdbc:sqlanywhere:uid=user;pwd=xxxx;eng=xx_sql;database=dummy;links=tcpip(host=xx.xx.xx.xx)

Firstly ensure that you point the database file to the SQL Anywhere Server and restart the server.
Secondly analyze your database logs, check if you can trace the connectivity with SQL PLUS or any other database connectivity tools.
If you are able to solve it, then that's fine or else I suspect that the issue to be related to this issue on SO here
As per this question, please make the following changes and I guess that the issue should be resolved
jdbc:sqlanywhere:Server=yourservername;uid=user;pwd=xxxx;port=2638;eng=xx_sql;database=dummy;links=tcpip(port=2638)
It is mandatory to mention the use of TCP/IP protocol to yourJDBC driver through the connection string above!
Hope this helps!

Java PostgreSQL connection over VPN

I have a Java application that needs to connect to a remote PostgreSQL database over a VPN. Here is the relevant code:
Class.forName("org.postgresql.Driver");
Connection con = null;
con = DriverManager.getConnection("jdbc:postgresql://" + sqlHost + ":" + sqlPort + "/mydb", username, password);
This throws the error
org.postgresql.util.PSQLException: FATAL: pg_hba.conf rejects connection for host "172.16.7.5", user "xxxxx", database "xxxxx", SSL off
The Host IP address in sqlHost is actually 192.168.12.55, but if you notice the error message says that it is connecting to host 172.16.7.5 (which is the IP address assigned by the VPN).
I am able to connect to this PostgreSQL database using the exact same connection parameters on the exact same VPN using PGAdmin and using Python's psocopg2 module. Here is the equivalent Python code:
conn = psycopg2.connect("dbname=mydb user="+username+" password="+password+" host="+sqlHost+" port="+sqlPort)
Why in the world is only Java having problems with this? Since the connection works over PGAdmin and Python, I assume there is some setting in Java that I am using incorrectly, but I can't find anything.
EDIT: After reading into PostgreSQL docs a little more, I found that the issue with it listing the wrong hostname is not part of the issue but rather just the way PostgreSQL sees my computer over the VPN. Problem is still not solved, however.

Okay, I fixed this myself. The problem had nothing to do with the VPN but rather with the fact that Java by default does not try any sort of SSL connection by default whereas PGAdmin and psycopg2 do.
The solution was to add the following parameters to my connection url:
ssl=true&sslfactory=org.postgresql.ssl.NonValidatingFactory

I'm not sure if this might be the problem, but I've experienced similar problems in the past trying to connect to a database with VPN turned on.
Try running your application with this JVM argument passed at application launch time:
-Djava.net.preferIPv4Stack=true
See also this answer for a more permanent solution.

GlassFish Server does not connect to SQL database (error w.r.t. SQL driver)

I am using a brand new developing pc and need to test a personal application that runs on a local GlassFish server 3.1.2 and should connect with a local SQL database called 'funkOneDB' (my IDE is NetBeans 7.2.1). But I can't get the GlassFish server to connect with the database, and the problem seems to be related to the (place of the) SQL driver in the GlassFish Server's directories (more problem specifics in a few lines).
I am fairly certain I correctly set up the related JDBC Resource and Connection Pool on the GlassFish Server (as I mimic a set-up already existing and working properly on another developing pc).
The Resource specifics are:
jndi name: jdbc/FunkResource
pool name: FunkPool
The (most important) Pool specifics are:
pool name: FunkPool
resource type: javax.sql.Datasource
datasource classname: com.mysql.jdbc.jdbc2.optional.MysqlDataSource
additional properties correspond to the specifics in the XML GlassFish-resources of the application (username, password, url, etc.; no problems there)
I first placed the necessary SQL driver in the GlassFish Server's directories, i.e. the file mysql-connector-java-5.1.18-bin.jar at ..\GlassFish3\GlassFish\domains\domain1\lib\ext.
Yet, when I perform a ping test from the JDBC Pool 'FunkPool' at the GlassFish server, I get the following error:
Ping Connection Pool failed for FunkPool. WEB9031: WebappClassLoader unable to load resource [com.mysql.jdbc.SQLError], because it has not yet been started, or was already stopped Please check the server.log for more details.
In the server.log I only find the following extra logging exception and failure info:
(i) Exception while creating an unpooled [test] connection for pool [ FunkPool ], WEB9031: WebappClassLoader unable to load resource [com.mysql.jdbc.SQLError], because it has not yet been started, or was already stopped
(ii) RestResponse.getResponse() gives FAILURE. endpoint = 'http://localhost:4848/management/domain/resources/ping-connection-pool.json'; attrs = '{id=FunkPool}'
Note however, that when I ping the database funkOneDB from my IDE NetBeans via jdbc:mysql://localhost:33066/funkOneDB, it's succesful. As already mentioned, the credentials and other data I use for this IDE-based ping are the same data I use in the JDBC Connection Pool.
I searched for the problem also on stackoverflow for some. And I did find some people talking about it, like
Glassfisch MySQL ping ERROR (no answer by anybody), or
Struggling to create MySQL Connection Pool on Glassfish (tried that solution, i.e. putting the SQL driver one level up in ..\GlassFish3\GlassFish\domains\domain1\lib\, but this creates other errors, even after restarting the Glassfish server), or
GlassFish not loading connector
(even tried this solution, no succes).
Can somebody help me solve this problem? Many thanks in advance!
With kind regards,
Heinz

Place the mysql driver in the lib folder of your project. Then do a clean-and-build. It's also helpful to have netbeans communicate directly with your database. This will allow you to view the database structure and the contents of your database right from your IDE. For help integrating MySQL with netbeans, look here: netbeans.org/kb/docs/ide/mysql.html

My friend, i had this same exception:
RestResponse.getResponse() gives FAILURE. endpoint = 'http://localhost:4848/management/domain/resources/ping-connection-pool.json'; attrs = '{id=FunkPool}'
The cause of my error was that, i put wrong credentials. Check your credentials in your client DB App (SQL Developer, for example).

I had the same problem with SQL server and Netbeans. To resolve it, i put the sqljdbc.jar in the java direcory "Java\jdk1.8.0_121\lib directory" and it works :)
I've just spebnt 10 hours on this bug.