Spring project cannot connect to the database - java

PLSQL can connect to oracle, but the project can not be connected, it will report errors when it is started, but it should not be the problem of code, because everyone of the code is pulled down from git.
I've tried re-installing jdk, re-pulling maven library, and even installing virtual machines, is still not good, or report the same error.

The error occurs when your database is down hence the connection refused error or your credentials are wrong. It would help if we could look at your code.

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Microsoft.Azure.Storage.Common: No connection could be made because the target machine actively refused it

Good morning, I'm developing an Azure Function in Java with #TimerTrigger. When I'm trying to run it, the system throws me:
The listener for function 'ABC123' was unable to start.
Microsoft.Azure.Storage.Common: No connection could be made because the target machine actively refused it.
Do you know if it is some additional configuration on my machine or that the Azure emulator needs some additional configuration?
Thank you very much!

IntelliJ not connecting to internet when my organization vpn is connected?

I tried to make gradle build, but intellij not downloading my dependency.
I am connected to my organization VPN, also tried automatic HTTP proxy
and custom vm argument no luck. I tried test connection in proxy settings it failing with VPN.
But without VPN test connection is success. Week before both ways its working. Can't understood sudden problem. Any solutions
Intellij Version 2019.1.2
I didn't encounter this problem myself, but from what I see in the internet, this is most likely not an IDEA problem, but a "Grandle through VPN" problem.
Some googling shows up next:
How to configure Grandle with VPN
Example of fixing SBT proxy in IDEA

Java Socket Permission error

Please help me resolve the following Java error msg when attempting to make a remote connection to a device in my office. I can connect from another CPU to the device, but not from my laptop. So, I know its a file in my laptop config somewhere. I have updated Java several times. Can someone tell me which file it is and exactly how to resolve this?
Also, the URL socket is supposed to be 5800...but the error msg shows socket 5900 for some reason!
Error: access denied (“java.netSocketPermission””172.30.150.88:5900””connect,resolve”)
Can someone tell me which file it is and exactly how to resolve this?
It is not possible. The location of that configuration file depends entirely on the Java application you are running.
If you were running Linux, I would say "use find and grep to search for the file".
The other thing to note is that you appear to have a Java security exception. That suggests that on your laptop the code is being run in a security sandbox. If that is the case, there is a distinct possibility that it is blocking all connects ... and that fixing the port number won't solve the problem.

Unable to connect to server database from java desktop application

I created a java desktop application. I am trying to connect this application to mysql
server database. But it is throwing socket exception. I tried in all the ways to solve this issue
but none of them worked for me. The problem which I got is mentioned in this link http://ubuntuforums.org/archive/index.php/t-849637.html
Please help me in this regard.
Will be really thankful..
According to your respnose on Oct 3'12 at 10:27, you already found out this is not Java related.
Fix your network problem:
ensure MySQL is really running
ensure you use correct IP/port
ensure no firewall is blocking traffic

Oracle JDBC : invalid username/password (ora-01017)

I have a strange problem with jdbc connection to an oracle database server.
We've applications on a tomcat server running. These application use an oracle database. All applications use the same credentials.
Applications running fine the whole day. At night there is no activity. In the morning we get a few (2 or 3) ORA-01017 (invalid username/password) errors when the applications trying to reconnect themselves to the database.
Then reconnection works and the applications will operate normal.
This works for some days (around 5 days) and then one or more of the application block! All reconnection attempts fail.
We've traced network communication and found that if the connection fails with ORA-01017 NO CREDENTIALS where sent.
Of course no one touches the system at night.
One attempt for a workaround is that we restart the tomcat server every morning at 6 o'clock to clean up every connection cache or pool. It does not help.
Whats wrong? Any ideas?
The continued 5 day interval in the appearance of a total blockage (while restating every day) looks very strange to me.
Config :
Database Oracle 10.2, JDBC Driver 11.2 thin, tomcat 6.0.24, JDK 6, OS is windows, some of the applications are Dialogs for the Avaya Voice Portal 5.0.
Our own (non VP) applications use simple Connections (no pooling).
The system was originally setup on a Windows 2003 server with a WAN between apserver and tomcat server.
The system is now migrated to a linux (CentOS) server near the database server and works fine. No ORA-01017 anymore.
For me incompatible version of OracleDriver was causing this issue Your application should either register oracle driver manually (which jar that I needed to work with was doing) or agter java 6 ojdbc.jar should be in the classpath for your application. So google compatible driver version for your oracle installation and either declare it in your pom file (with needed plugin to put it in the resulting jar) and reference it manually from code or put the ojdbc.jar somewhere your jar can see it Usefull links:
About connecting to oracle db: https://www.codejava.net/java-se/jdbc/connect-to-oracle-database-via-jdbc
About java classpath: https://docs.oracle.com/javase/7/docs/technotes/tools/windows/classpath.html
Odd. Some ideas:
Log the user name and password for a few days just to make sure they are correct. Some bug in the code might overwrite a value that you don't expect.
Consider to use JNDI with a connection pool provided by Tomcat. DBCP has some really advanced options to check whether a connection is still alive and how to reconnect it. After that, you shouldn't see any connection related issues in your logs anymore. This would also improve security because none of the apps need to know the DB password anymore.
It might be a problem with resource leaks (happens if an app never returns the connection) but I'd expect a different error message, then.
Some databases (DB2, H2) allow to create views that make remote tables from other databases visible like local tables. Not sure whether Oracle supports this but if it does, then maybe the user name/password for this remote table is wrong.
Also consider the points in this blog post: Oracle ORA-01017 tips
At first glance, nothing in the post could cause your problems but maybe some script is manipulating the tnsnames.ora (for example distributing a new copy).
Or the DBA disabled all users for the time of the daily backup.
I'd check Oracle listener and trace logs. As Aaron Digulla said, it does sound like some resource exhaustion.
As Nikita Poberezkin said, I checked my JDBC driver versions and saw it was different from our test server. I removed it and installed the same exact version of the test server and I guess it's solved now.

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