We Keep Coding

Trouble establishing a simple connection with JDBC to MySql, java.sql.SQLNonTransientConnectionException

I fail to establish a connection to a MySql database on an external server when I use the mysql-connector-java version 8.0.11+ (I was currently testing with 8.0.25). However I am able to create a connection when I use the older MySql connector mysql-connector-java version 5.1.49.
The version of the MySql Database is "8.0.25-15"
The code fails on the first line:
try (Connection conn = DriverManager.getConnection(DB_URL, USER, PASS);
{...}
Since I can connect though mysql-connector-java version 5.1.49, I first thought I could solve this problem by adding parameters to the DB_URL. I have experimented with a lot of parameters, but no luck:
useSSL=false
serverTimezone=GMT
useUnicode=true
characterEncoding=utf-8
passwordCharacterEncoding=utf-8
connectionCollation=utf8mb4_bin
autoReconnect=true
failOverReadOnly=false
maxReconnects=10
cacheServerConfiguration=false
The error I always receive is:
java.sql.SQLNonTransientConnectionException: Could not create connection to database server.
Caused by: java.lang.NullPointerException: Cannot invoke "String.toUpperCase(java.util.Locale)" because "javaEncoding" is null
at com.mysql.cj.CharsetMapping.getMysqlCharsetForJavaEncoding(CharsetMapping.java:552)
at com.mysql.cj.CharsetMapping.getCollationIndexForJavaEncoding(CharsetMapping.java:585)
at com.mysql.cj.protocol.a.NativeServerSession.configureCharacterSets(NativeServerSession.java:452)
at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1329)
at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:866)
A month ago, I did not have this problem, so I suspect the cause is a change in the database (I am not tbe database Administrator).
When I debug, the error seems to be caused because the program requests the "character_set_system" variable from MySql, which is"utf8mb3" (instead "utf8" or "utf8mb4").
I suspect that changing the database variable "utf8mb3" to "utf8" might solve this problem? But I am not certain and I cannot simply change this value because the database is hosted by an external company. I have typed "Show Variables" and "Show Global Variables" in a MySql editor for your information:
A screenshot of the DB variables concerning language.
Alternatively I would like to tell java to ignore "character_set_system". It seems that Java first looks for "local.character_set_results", but this variable returns null despite that "character_set_results" is defined in the database.
I hope someone can help me with this problem.
Kind Regards
Steven

Connect To SQL Server With Windows Authentication From A Linux Machine Through JDBC

I want to be able to connect to a SQL Server using jdbc and windows authentication.
I saw some answers on the internet saying i should add the following property to the connection string:
integratedSecurity=true;
And also add
sqljdbc_auth.dll
To the java path.
But this, as far as i understand applies only when i'm connecting from a Windows machine.
When i try this on a Linux machine i get:
java.sql.SQLException: This driver is not configured for integrated authentication
My question is how do I do it from a Linux machine.
Thanks

Well, eventually I answer my own question:
This is not possible to use Windows authentication from a linux machine using the Microsoft JDBC driver.
This is possible using the jTDS JDBC driver using the following connection string:
jdbc:jtds:sqlserver://host:port;databaseName=dbname;domain=domainName;useNTLMv2=true;
Thank you all for all the comments

TL;DR
It is not possible to use native Windows Authentication for JDBC connections to MSSQL from a JVM running on Linux.
This MSDN article explains the authentiation methods with JDBC on Linux, potential errors, and available options:
https://blogs.msdn.microsoft.com/psssql/2015/01/09/jdbc-this-driver-is-not-configured-for-integrated-authentication/
...in the JDBC 4.0 driver, you can use the authenticationScheme
connection property to indicate how you want to use Kerberos to
connect to SQL. There are two settings here.
NativeAuthentication (default) – This uses the sqljdbc_auth.dll and is specific to the Windows platform. This was the only option
prior to the JDBC 4.0 driver.
JavaKerberos – Makes use of the Java API’s to invoke kerberos and does not rely on the Windows Platform. This is java specific and not
bound to the underlying operating system, so this can be used on both
Windows and Linux platforms.
...
The following document outlines how to use Kerberos with the JDBC
Driver and walks through what is needed to get JavaKerberos working
properly.
Using Kerberos Integrated Authentication to Connect to SQL Server
http://msdn.microsoft.com/en-us/library/gg558122%28v=sql.110%29.aspx

For those who are using DBeaver the way to connect to the SQL Server Database is:
In order to connect to the SQL Server from Linux Debian using DBeaver
1.- Select SQL Server jTDS driver
2.- Enter the connection information
3.- Go to Driver Properties tab and add the domain, user, password
Just as a note, in some post I found that they needed to change the property USENTLMV2 to TRUE but it worked for me either by putting the USERTLNMV2 in true or false.
A problem that I found was that when I was trying to connect to the database using my user and password the next error was thrown:
Login failed. The login is from an untrusted domain and cannot be used with Windows authentication.
This error was thrown because of my user was about to expire. I tried with another AD user and it could connect.

I know this is kind of an older topic but in case Google sends people here:
There are two main JDBC drivers for SQL Server. One is from Microsoft and the other from jTDS. jTDS can, amazingly, connect using Windows auth (NTLM) from other platforms, including Linux, as described here: http://jtds.sourceforge.net/faq.html#windowsAuth. It can, of course, also use SQL-authenticated logins. SQL-authenticated logins are no harder to use from any OS than any other, so don't forget about those an option.
The version provided by Microsoft is the one from which #mjn provided a quote from the documentation. It is able to connect using Windows authentication by specifying integratedSecurity=true, authenticationScheme=javaKerberos, and authentication=NotSpecified.
It is tricky to get this working even if you don't go out of your way to find more confusion, so always keep in mind which driver you are using - and tell us in these posts so that you can get more specific help.

This JDBC URL is validated to work with latest Microsoft SQL Server JDBC driver:
jdbc:sqlserver://[server]:[port];database=[db\;trustServerCertificate=true;integratedSecurity=true;user=[user without domain];password=[pw];authenticationScheme=NTLM;domain=[domain];authentication=NotSpecified
Example:
jdbc:sqlserver://mysql.myorg.com:1433;database=mydb;trustServerCertificate=true;integratedSecurity=true;user=myuser;password=mypwd;authenticationScheme=NTLM;domain=ad.myorg.com;authentication=NotSpecified

I was able to connect to a SQL Server 2016 Data Mart and JDBC connection Microsoft JDBC Driver using Windows Authentication using the following script on a Ubuntu Linux Docker Image running on Windows 10.
# initializes spark session
from pyspark.sql import SparkSession
spark = SparkSession\
.builder\
.master('local[*]')\
.appName('FDM')\
.config("spark.driver.extraClassPath","pyspark_jars/*")\
.config('spark.executor.memory', '4g')\
.config('spark.driver.memory', '16g')\
.config('spark.executor.cores', '4')\
.getOrCreate()
jdbc_url = '''jdbc:sqlserver://SERVER;databaseName=DBNAME;trustServerCertificate=true;integratedSecurity=true;user=USERID;password=PASSWORD;authenticationScheme=NTLM;domain=US;authentication=NotSpecified'''
spark_df = spark.read\
.format("jdbc")\
.option("url", jdbc_url)\
.option("driver","com.microsoft.sqlserver.jdbc.SQLServerDriver")\
.option("query", 'select top(1000) * from SCHEMA.TABLE')\
.option("fetchsize", 100000)\
.load()
spark_df.write.csv('TEST.csv', mode = "overwrite", header=True)

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.

java.sql.SQLException: No suitable driver found for localhost/buddhiedgeserver_db [duplicate]

This question already has answers here:
The infamous java.sql.SQLException: No suitable driver found
(21 answers)
Closed 7 years ago.
I am trying to connect to a MySQL 5.5 database as follows:
public void getCon() throws SQLException, ClassNotFoundException {
Class.forName("com.mysql.jdbc.Driver");
Connection con=DriverManager.getConnection("localhost/buddhiedgeserver_db","root","amma");
System.out.println("Connection"+con);
}
However, it is throwing an exception
java.sql.SQLException: No suitable driver found for localhost/buddhiedgeserver_db.
How is this caused and how can I solve it? I am using MyEclipse version 9.1 and I have included the mysql.jar in the classpath.

java.sql.SQLException: No suitable driver found
This means that the JDBC URL is not accepted by any of the loaded drivers as per the Driver#acceptsURL() contract.
You've correctly loaded the MySQL JDBC driver and it has not thrown a ClassNotFoundException, so that part is fine. However, your JDBC URL is completely wrong. It does not conform any syntax as specified in MySQL JDBC driver documentation. Here's a cite of relevance:
JDBC URL Format
The JDBC URL format for MySQL Connector/J is as follows, with items in square brackets ([, ]) being optional:
jdbc:mysql://[host][,failoverhost...][:port]/[database] »
[?propertyName1][=propertyValue1][&propertyName2][=propertyValue2]...
If the host name is not specified, it defaults to 127.0.0.1. If the port is not specified, it defaults to 3306, the default port number for MySQL servers.
jdbc:mysql://[host:port],[host:port].../[database] »
[?propertyName1][=propertyValue1][&propertyName2][=propertyValue2]...
Here is a sample connection URL:
jdbc:mysql://localhost:3306/sakila?profileSQL=true
Your JDBC URL of localhost/buddhiedgeserver_db does absolutely not match the documented MySQL JDBC URL format. Fix it accordingly.
jdbc:mysql://localhost/buddhiedgeserver_db

Issue in DB2 Express-C Connection while sharing a database over LAN from Java

I have installed DB2 Express-C 9.7.5. It was installed on a Windows 7 (64-bit) machine and I created a database, TESTXA. The connection mechanism used in my application is:
Class.forName("com.ibm.db2.jcc.DB2Driver").newInstance();
Connection conn = DriverManager.getConnection("jdbc:db2://ABCCOMPUTER:50000/TESTXA", db2UserName, db2PassWord);
The connection successfully created on ABCCOMPUTER with the above Java code. But when I use the same Java code to create a DB2 connection from another system over LAN, for example, XYZCOMPUTER (Windows 7 machine) with the same db2UserName/db2PassWord, throws an exception:
com.ibm.db2.jcc.am.io: DB2 SQL Error: SQLCODE=-204, SQLSTATE=42704, SQLERRMC=USER.XA4APP, DRIVER=3.57.82
Which indicates "Connection authorization failure occurred. Reason: User ID or Password invalid."
In my application, I need to create a database in DB2 which can be accessed from other systems on a LAN. What should be looked into on XYZCOMPUTER to resolve this issue?
(FYI: This is no issue of DB2 database sharing in Windows XP machines. The above mechanism works properly.)

This should be no issue of Java JDBC. It must be the case of a Windows 7 security issue because the DB2 type 4 driver uses the same format of the connection string whether it's a case of your own system or a remote system. You can try to run your application/tool as 'Run as Administrator'.