I launched the hazelcast server with my model classes that I do not recall seeing with the sample client - the error is copied below:
Couldn't connect to discovered master! tryCount: 50
Any suggestions on troubleshooting this would be great
If using multicasting, try switching over to tcp based connections. If that does not help, try checking if there are more detailed exceptions (or perhaps add one from where the exception is being generated).
On linux, I believe you can check for multicasting permissions through ifconfig eth0 - result should give you a value for multicasting.
Related
I installed Java on my Windows 10 machine and downloaded Metabase.jar, and ran it.
Now I could access metabase at localhost:3000
But I'm unable to setup my SQL Server Database as Data reference.
I'm either getting:
Couldn't connect to the database. Please check the connection details.
or
Timed out after 5000 milliseconds.
Anyone who has done Metabase - SQL Server connection successfully?
Currently, as of Metabase version 0.30.x the answer depends on if you can use a user configured directly on SQL Server or not:
The easier option to setup is with a user configured directly on SQL Server. Then config is just Name: (anything), Host: (full name), Database Name, Username, Password as you would expect. (I believe you should NOT fill in the Windows domain).
On Windows only you can also use native integrated authentication with sqljdbc_auth.dll, just specify integratedSecurity=true connection property (and optionally authenticationScheme=NativeAuthentication). I found if I dropped the x64 sqljdbc_auth.dll in my <java path>\jre\bin folder it was picked up. Metabase config as in the screenshot below, apart from dropping authenticationScheme=JavaKerberos
The cross platform authenticationScheme=JavaKerberos option to use Windows Authentication with a domain user is still doable, but harder. It's these steps:
Create a krb.conf and verify login works with <Java path>\bin\kinit.exe [user]. Here's a template edited to match the Metabase database setup in the screenshot below.
Start the Metabase.jar file with parameters to load the krb.conf. It works for me with java -Djava.security.krb5.conf=c:/<path>/kerberos/krb.conf -jar metabase.jar.
Now configure the database settings in Metabase according to the screenshot below
Moment of truth! ...
Optional: Still not working? Maybe your SQL Server isn't configured for Kerberos? Maybe you need SPN setup? Maybe you need to specify a java.security.auth.login.config (I have not experienced any of that myself, only thing I can offer is you scroll to the bottom of this post and dive in then edit your question with where you got to and what config you have)
Metabase SQL Server setup using Kerberos:
For background, current (August 2018) very long :| sum up with lots of links of how to connect to SQL Server is here in a Metabase discussion topic Note: In v0.30.0 an issue with dynamic port handling (particularly for people using named instances) was fixed.
Related: A neat StackOverflow answer on Kerberos on a Mac
If you are connecting to a "Named Instance" ({SERVER_NAME}/{INSTANCE_NAME}) instead of "Default Instance" ({SERVER_NAME}), your server may be configured to use Dynamic Port.
A quick dirty fix is you can find the current port with below scripts and then use it on Metabase connection parameters. But this port most probably will change when service restart occurs.
SELECT DISTINCT
local_tcp_port
FROM sys.dm_exec_connections
WHERE local_tcp_port IS NOT NULL
or
USE master
GO
Xp_readerrorlog
(look for "Server is listening on ..." line)
A Cleaner way is setting port for your instance by "SQL Server Configuration Manager" - "SQL Server Network Configuration" - "TCP/IP" - Right Click properties - "TCP Dynamic Ports" (There should be 0 and it should be deleted) and "TCP Port" (New default port should be set here). And also "SQL Server Browser" service should run. A more detailed explanation is here
I am new to Oracle, and am trying to run a simple example code with Java, but am getting this error when executing the code.. I am able to start up the listener via CMD and am also able to run SQL Plus. Can anyone give me a hand and tell me what I might be doing wrong?
Update:
I am using JDBC.
Database is local, and I actually had it working but it stopped working just today. I'm not really sure why though. Would you mind giving me some procedures to follow by since I don't know much.
Either:
The database isn't running
You got the URL wrong
There is a firewall in the way.
(This strange error message is produced by Oracle's JDBC driver when it can't connect to the database server. 'Network adapter' appears to refer to some component of their code, which isn't very useful. Real network adapters (NICs) don't establish connections at all: TCP protocol stacks do that. It would have been a lot more useful if they had just let the original ConnectException be thrown, or at least used its error message and let it appear in the stack trace.)
I had the same problem, and this is how I fixed it.
I was using the wrong port for my connection.
private final String DB_URL = "jdbc:oracle:thin:#localhost:1521:orcll"; // 1521 my wrong port
go to your localhost
(my localhost address) : https://localhost:1158/em
login
user name
password
connect as --> normal
Below 'General' click on LISTENER_localhost
look at you port number
Net Address (ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1522))
Connect to port 1522
Edit you connection
change port 1521 to 1522.
done
Another thing you might want to check that the listener.ora file matches the way you are trying to connect to the DB. If you were connecting via a localhost reference and your listener.ora file got changed from:
HOST = localhost
to
HOST = 192.168.XX.XX
then this can cause the error that you had unless you update your hosts file to accommodate for this. Someone might have made this change to allow for remote connections to the DB from other machines.
I figured out that in my case, my database was in different subnet than the subnet from where i was trying to access the db.
I had this error when i renamed the pc in the windows-properties. The pc-name must be updated in the listener.ora-file
Most probably you have listener configured wrongly, the hostname you specify in connection string must be the same as in the listener.
First check the Firewall and network related issues.
Check if Oracle Listener service is available and running. If not you may use Oracle Net Configuration Assistant tool to add and register new listener.
If the above steps are ok then you need to configure Oracle Listener appropriately. You may use Oracle Net Manager tool or edit “%ORACLE_HOME%\network\admin\listener.ora” file manually.
There are 2 options that need to be considered carefully:
Listening Locations associated with the Listener – Hostname(IP) and Port in Listening Location must exactly match the ones used in the connection string.
For example, if you use 192.168.74.139 as target hostname, then there must be Listening Location registered with the same IP address.
Also make sure the you use the same SID as indicated in Database Service associated with the Listener.
https://adhoctuts.com/fix-oracle-io-error-the-network-adapter-could-not-establish-the-connection-error/
IO Error: The Network Adapter could not establish the connection (CONNECTION_ID=iKQM6lBbSLiArrYuDqud8A==)
if you are facing this issue
1- make sure you have downloaded oracle databases like oracle 11g,19c, 21c, or any latest databases.
2- search for services in your computer or type win+r then services.mis then search for oracleservice you will find orcl or xe or any other sid like oracleserviceorcl;
after that you can test your connection using sql developer, sql plus or cmd
To resolve the Network Adapter Error I had to remove the - in the name of the computer name.
In my case, I needed to specify a viahost and viauser. Worth trying if you're in a complex system. :)
For me the basic oracle only was not installed. Please ensure you have oracle installed and then try checking host and port.
I was having issues with this as well. I was using the jdbc connection string to connect to the database. The hostname was incorrectly configured in the string. I am using Mac, and the same string was being used on Windows machines without an issue. On my connection string, I had to make sure that I had the full url with the appending "organizationname.com" to the end of the hostname.
Hope this helps.
Just try to re-create connection. In my situation one of jdbc connection stopped working for no reason. From console sqlplus was working ok.
It took me 2 hours to realize that If i create the same connection - it works.
A client application has been built using Jdeveloper 10.1.3.2 and it is running on OC4J server. This application is sending data to external server application. It is working for quite long time without any issue. Lately a connection issue occurred and the following stack trace is generated:
com.sun.xml.ws.client.ClientTransportException: HTTP transport error: java.net.SocketException: Connection reset
at com.sun.xml.ws.transport.http.client.HttpClientTransport.getOutput(HttpClientTransport.java:133)
at com.sun.xml.ws.transport.http.client.HttpTransportPipe.process(HttpTransportPipe.java:153)
at com.sun.xml.ws.transport.http.client.HttpTransportPipe.processRequest(HttpTransportPipe.java:93)
at com.sun.xml.ws.transport.DeferredTransportPipe.processRequest(DeferredTransportPipe.java:105)
at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:629)
at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:588)
at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:573)
at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:470)
at com.sun.xml.ws.client.Stub.process(Stub.java:319)
at com.sun.xml.ws.client.sei.SEIStub.doProcess(SEIStub.java:157)
at com.sun.xml.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:109)
at com.sun.xml.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:89)
at com.sun.xml.ws.client.sei.SEIStub.invoke(SEIStub.java:140)
at $Proxy44.sendRem(Unknown Source)
After goggling I found out a good discussion about the error sockets - What's causing my java.net.SocketException: Connection reset? .One answer in this link says that the issue mostly from the client side because if it is from the server side the exception will be (SocketException reset by peer).
What I did:
I tried out to increase the socket time out for the OC4J with the help of this form How to change OC4J HTTP Timeout. What I did is I changed the propriety oracle.j2ee.http.socket.timeout to be 5000 instead of 500 (10 times longer)
But the error still there. So, any suggestion to over come this issue?
Note: I able to use telnet command for external server IP and Port and it is working fine.
-------------------------------------------------------- Update 1 --------------------------------------------------------
I increase the server clock skew where the client application is running using the following command on server start up:
-Dweblogic.wsee.security.clock.skew=72000000
-Dweblogic.wsee.security.delay.max=72000000
But no luck, problem is not resolved.
-------------------------------------------------------- Update 2 --------------------------------------------------------
I realized that the problem is not from application at all; I test the external URL using SoapUI and I got the same error Connection rest. I think this new update clreay shows that there is nothing wrong with program code. But I need to know where to go or check now. Where is the starting point now to overcome the issue. Any clue will be helpful.
As you can see from Update 2 in the question, the problem was not from the client application because same error occurred from SoapUI.
The problem was that the machine where the client application was running have low bandwidth which was not enough for APIs communication. Using simple speed test , I found out that the upload bandwidth was low comparing to minimum requirements given by server application team.
I concluded this fact by monitoring the network resource using Resource Monitor in Windows while the client application was running and by using online speed check
To solve the issue, the machine bandwidth has to be increased where the client application is running.
I'm getting the following error when i'm trying to connect via RMI to a JBoss application
javax.naming.CommunicationException [Root exception is java.lang.ClassNotFoundException: org.jboss.proxy.ClientContainer]
This error occurs only after enabling IPtables on a linux server.
At the moment, we use this application as a logging tool between 2 servers, but it all Ports to be open because RMI uses random ports for the export of objects if i'm not mistaken
We have tested with some small test applications and the following is a viable solution when using firewalls with RMI:
UnicastRemoteObject.exportObject(server, 1244);
I export the object over port 1244
The following ports are open at this moment:
1244: The RMI-export object
1066: Binding with RMI on the server
1099: Registering on the management server
Is there anybody that could push me in the right direction to get this implementation working?
Thanks in advance!
I am trying to connect to an Oracle database from my Java application. I am using oracle.jdbc.driver.OracleDriver, Version : 0/1 to connect to the database. But DriverManager.getConnection() is giving me the "The network adapter could not establish the connection". This is not happening evertime. Its happening sometimes only, may be once in 8-10 times. The stack trace am getting is :
Driver Class : oracle.jdbc.driver.OracleDriver, version 0/1
java.sql.SQLException: Io exception: The Network Adapter could not establish the connection
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:179)
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:334)
at oracle.jdbc.ttc7.TTC7Protocol.handleIOException(TTC7Protocol.java:3678)
at oracle.jdbc.ttc7.TTC7Protocol.logon(TTC7Protocol.java:352)
at oracle.jdbc.driver.OracleConnection.<init>(OracleConnection.java:365)
at oracle.jdbc.driver.OracleDriver.getConnectionInstance(OracleDriver.java:547)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:347)
at java.sql.DriverManager.getConnection(DriverManager.java:316)
at java.sql.DriverManager.getConnection(DriverManager.java:297)
Since I am not getting this everytime, I am not able to guess that there is any connectivity issue. I can see lots of developers have the same problem, but for them it happens everytime. Please help me, since i am literally stuck in solving this problem.
I was having a similar problem, I tried using the IP address instead of the host name in the database URL, and it worked for me.
Example jdbc:
...(DESCRIPTION=(ADDRESS.....(HOST=1.1.1.1)..)
This is probably a network issue:
Is there a firewall that's giving you trouble? Try to telnet to the port. Is the firewall stateful?
Is the DNS too slow (use IP address instead of hostname, try DNS lookup)
Do you close the connections? Are you overloading the Listener?
I would have a closer look and perhaps set a break point in
at oracle.jdbc.ttc7.TTC7Protocol.handleIOException(TTC7Protocol.java:3678)
to see the precise IOException handled. This will tell you the underlying cause, which can help diagnose the problem.