Develop Reference

MongoDB atlas, connection not working

I just created a free MongoDB atlas cluster instance. But somehow I am failing to connect it from my application as well as from the MongoDB Compas.
I get below error when I try to run my application.
Caused by: com.mongodb.MongoTimeoutException: Timed out after 30000 ms while waiting for a server that matches WritableServerSelector. Client view of cluster state is {type=UNKNOWN, servers=[{address=experimental-1-epdri.mongodb.net:27017, type=UNKNOWN, state=CONNECTING, exception={com.mongodb.MongoSocketException: experimental-1-epdri.mongodb.net}, caused by {java.net.UnknownHostException: experimental-1-epdri.mongodb.net}}]
at com.mongodb.connection.BaseCluster.createTimeoutException(BaseCluster.java:377) ~[mongodb-driver-core-3.4.2.jar:na]
at com.mongodb.connection.BaseCluster.selectServer(BaseCluster.java:104) ~[mongodb-driver-core-3.4.2.jar:na]
at com.mongodb.binding.ClusterBinding$ClusterBindingConnectionSource.<init>(ClusterBinding.java:75) ~[mongodb-driver-core-3.4.2.jar:na]
at com.mongodb.binding.ClusterBinding$ClusterBindingConnectionSource.<init>(ClusterBinding.java:71) ~[mongodb-driver-core-3.4.2.jar:na]
at com.mongodb.binding.ClusterBinding.getWriteConnectionSource(ClusterBinding.java:68) ~[mongodb-driver-core-3.4.2.jar:na]
at com.mongodb.operation.OperationHelper.withConnection(OperationHelper.java:411) ~[mongodb-driver-core-3.4.2.jar:na]
at com.mongodb.operation.CreateIndexesOperation.execute(CreateIndexesOperation.java:144) ~[mongodb-driver-core-3.4.2.jar:na]
at com.mongodb.operation.CreateIndexesOperation.execute(CreateIndexesOperation.java:71) ~[mongodb-driver-core-3.4.2.jar:na]
at com.mongodb.Mongo.execute(Mongo.java:845) ~[mongodb-driver-3.4.2.jar:na]
at com.mongodb.Mongo$2.execute(Mongo.java:828) ~[mongodb-driver-3.4.2.jar:na]
at com.mongodb.MongoCollectionImpl.createIndexes(MongoCollectionImpl.java:491) ~[mongodb-driver-3.4.2.jar:na]
at com.mongodb.MongoCollectionImpl.createIndex(MongoCollectionImpl.java:458) ~[mongodb-driver-3.4.2.jar:na]
at org.axonframework.mongo.eventsourcing.eventstore.AbstractMongoEventStorageStrategy.ensureIndexes(AbstractMongoEventStorageStrategy.java:201) ~[axon-mongo-3.0.5.jar:3.0.5]
at org.axonframework.mongo.eventsourcing.eventstore.MongoEventStorageEngine.ensureIndexes(MongoEventStorageEngine.java:123) ~[axon-mongo-3.0.5.jar:3.0.5]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_111]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_111]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_111]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_111]
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:366) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:311) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:134) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
... 76 common frames omitted
Process finished with exit code 1
On Compas it simply says MongoDB instance isn't running at this place. I have checked my cluster and I see below.
But still I can't connect to mongo cluster. Further more I tried with `Mongo CLI as well where I found error as shown below.
Below is the connection string that I get from the MongoDB atlas page.
mongodb+srv://admin_eventdb:<PASSWORD>#experimental-1-epdri.mongodb.net/test?retryWrites=true
Please help solve this.

Please try with:
Hostname: experimental-1-epdri.mongodb.net
SRV Record: checked
Authentication: Username / Password
Username: admin_eventdb
Password: <PASSWORD>
Authentication Database: admin
Replica Set Name:
Read Preference: Primary
SSL: System CA / Atlas Deployment
SSL Tunnel: None

I had the same issue. Via connection string using Java Driver 3.4 it would be:
mongodb://user:<PASSWORD>#cluster0-shard-00-00-ox90k.mongodb.net:27017,cluster0-shard-00-01-ox90k.mongodb.net:27017,cluster0-shard-00-02-ox90k.mongodb.net:27017/test?ssl=true&replicaSet=Cluster0-shard-0&authSource=admin&retryWrites=true
Instead of <PASSWORD> I wrote own password. admin1is my admin-user.
Updated: if you want to use drivers 3.7+, you need to write instead of format connection (and to avoid my issues above)
MongoClientURI uri = new MongoClientURI("mongodb+srv://admin:mypassword#cluster0-ox90k.mongodb.net/test?retryWrites=true");
MongoClient mongoClient = new MongoClient(uri);
another variant using MongoClients.create() (as of the 3.7 release),:
MongoClient mongoClient = MongoClients.create("mongodb+srv://admin:mypassword#cluster0-ox90k.mongodb.net/test?retryWrites=true");
Note: the password need to write not like mongodb://user:<mypassword>#..., just in format mongodb://user:mypassword#... without braces <>.

I point I mentioned
Please login to mongodb atlas
1.go to security section
2.network access
Then allow anywhere access that it's may be helps.

for Node.js : checkout Atlas MongoDB connection
const mongoose = require('mongoose');
const conStr = 'mongodb+srv://lord:<password>#cluster5-eeev8.mongodb.net/test?retryWrites=true&w=majority'
const DB = conStr.replace(
'<password>',
myPass
);
const DB = conStr.replace(
'test',
myDatabaseName
);
//remember mongoose.connect() return promise
mongoose
.connect(DB, {
usedNewUrlParser: true,
useCreateIndex: true,
useFindAndModify: false,
})
.then((con) => {
console.log(con.connection);
console.log('DB connection successful');
});

Just tried to use Atlas. This is the configuration that worked for me with Spring Boot 2.3.1.RELEASE
spring:
data:
mongodb:
database: sample_training
uri: mongodb+srv://<user>:<pass>#cluster0-hosturl.aws|gcp.mongodb.net/?retryWrites=true&w=majority

mongo java driver 3.4.3 replica set connection can't monitor members

Using : Ubuntu 16.04.3
I'm connecting to a replica set through mongodb java driver v3.4.3 (or 3.5.0) . I may create the MongoClient by providing the IPs , or the hostnames I have provided in the /etc/hosts file as such :
new MongoClient(
Arrays.asList(
new ServerAddress("X.X.Y.A",27017),
new ServerAddress("X.X.Y.B",27017),
new ServerAddress("X.X.Y.C",27017))
);
or
new MongoClient(new MongoClientURI("mongodb://X.X.Y.A:27017/?replicaSet=my-rs"));
or
//myserver1 on /etc/hosts as X.X.Y.A myserver1
new MongoClient(new MongoClientURI("mongodb://myserver1:27017/?replicaSet=my-rs"));
in both cases , mongodb is trying to monitor the replica sets as "mongodb1" , "mongodb2" and "mongodb3" and keeps throwing the INFO Log and prevents the execution :
Oct 18, 2017 9:12:13 AM com.mongodb.diagnostics.logging.JULLogger log
INFO: Exception in monitor thread while connecting to server mongodb3:27017
com.mongodb.MongoSocketException: mongodb1
at com.mongodb.ServerAddress.getSocketAddress(ServerAddress.java:188)
at com.mongodb.connection.SocketStreamHelper.initialize(SocketStreamHelper.java:57)
at com.mongodb.connection.SocketStream.open(SocketStream.java:58)
at com.mongodb.connection.InternalStreamConnection.open(InternalStreamConnection.java:115)
at com.mongodb.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:113)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.net.UnknownHostException: mongodb1
at java.net.InetAddress.getAllByName0(InetAddress.java:1280)
at java.net.InetAddress.getAllByName(InetAddress.java:1192)
at java.net.InetAddress.getAllByName(InetAddress.java:1126)
at java.net.InetAddress.getByName(InetAddress.java:1076)
at com.mongodb.ServerAddress.getSocketAddress(ServerAddress.java:186)
... 5 more
Throwing the similar exceptions for "mongodb2" and "mongodb3" .
But when i add the mongodb1 etc rows on /etc/hosts file , everything works as :
X.X.Y.A mongodb1
X.X.Y.B mongodb2
X.X.Y.C mongodb3
This leads me to think that mongo driver is hardcodedly monitoring the N members of the replicaset as "mongodbN:port". Is this a bug on mongodb java driver or just incredibly useless way of doing it ?

Start Java/Play2.5 REST API without DB

I would like to start my Java/Play! Service even though the Database is not yet reachable. So far, if the database is not available the service stops. Is it possible in Play to try and reconnect every second or so without completely stopping the service and reconnecting to db as soon as connection is available.
Our application.conf currently looks like this:
play.evolutions.enabled=false
//play.db.pool=bonecp
db {
default.driver=org.postgresql.Driver
default.url="jdbc:postgresql://postgresdb.postgres:5432/postcode"
default.username="<username>"
default.password="<strong-password>"
}
play.db {
config = "db"
prototype.hikaricp = {
connectionTimeout = 250 milliseconds
initializationFailFast = false
readOnly = true
}
}
ebean.default = ["models.*"]
Currently I get the following logs:
2017-05-15 13:26:54.525 [error] postcode-play: Connection error:
org.postgresql.util.PSQLException: FATAL: remaining connection slots are reserved for non-replication superuser connections
Ort: Datei: postinit.c, Routine: InitPostgres, Zeile: 779.
Server SQLState: 53300
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2412)
at org.postgresql.core.v3.QueryExecutorImpl.readStartupMessages(QueryExecutorImpl.java:2538)
at org.postgresql.core.v3.QueryExecutorImpl.<init>(QueryExecutorImpl.java:122)
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:227)
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:194)
at org.postgresql.Driver.makeConnection(Driver.java:431)
at org.postgresql.Driver.connect(Driver.java:247)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:95)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:101)
2017-05-15 13:26:54.626 [error] postcode-play: Connection error:
org.postgresql.util.PSQLException: FATAL: remaining connection slots are reserved for non-replication superuser connections
Ort: Datei: postinit.c, Routine: InitPostgres, Zeile: 779.
Server SQLState: 53300
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2412)
at org.postgresql.core.v3.QueryExecutorImpl.readStartupMessages(QueryExecutorImpl.java:2538)
at org.postgresql.core.v3.QueryExecutorImpl.<init>(QueryExecutorImpl.java:122)
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:227)
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:194)
at org.postgresql.Driver.makeConnection(Driver.java:431)
at org.postgresql.Driver.connect(Driver.java:247)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:95)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:101)
.
.
.
Indicating that the server does not stop altogether but tries to connect to db multiple times which is as desired. But if the database becomes available the following logs are written:
2017-05-15 14:08:43.748 [error] postcode-play:
! #7430ed7gf - Internal server error, for (GET) [/?postcode=88682&country=DE] ->
play.api.Configuration$$anon$1: Configuration error[Cannot connect to database [default]]
at play.api.Configuration$.configError(Configuration.scala:155)
at play.api.Configuration.reportError(Configuration.scala:808)
at play.api.db.DefaultDBApi$$anonfun$connect$1.apply(DefaultDBApi.scala:48)
at play.api.db.DefaultDBApi$$anonfun$connect$1.apply(DefaultDBApi.scala:42)
at scala.collection.immutable.List.foreach(List.scala:392)
at play.api.db.DefaultDBApi.connect(DefaultDBApi.scala:42)
at play.api.db.DBApiProvider.get$lzycompute(DBModule.scala:72)
at play.api.db.DBApiProvider.get(DBModule.scala:62)
at play.api.db.DBApiProvider.get(DBModule.scala:58)
at com.google.inject.internal.ProviderInternalFactory.provision(ProviderInternalFactory.java:81)
Caused by: java.sql.SQLTransientConnectionException: HikariPool-4 - Connection is not available, request timed out after 5001ms.
at com.zaxxer.hikari.pool.HikariPool.createTimeoutException(HikariPool.java:548)
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:186)
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:145)
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:83)
at play.api.db.DefaultDatabase.getConnection(Databases.scala:142)
at play.api.db.DefaultDatabase.getConnection(Databases.scala:138)
at play.api.db.DefaultDBApi$$anonfun$connect$1.apply(DefaultDBApi.scala:44)
at play.api.db.DefaultDBApi$$anonfun$connect$1.apply(DefaultDBApi.scala:42)
at scala.collection.immutable.List.foreach(List.scala:392)
at play.api.db.DefaultDBApi.connect(DefaultDBApi.scala:42)
Caused by: org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:265)
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:194)
at org.postgresql.Driver.makeConnection(Driver.java:431)
at org.postgresql.Driver.connect(Driver.java:247)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:95)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:101)
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:341)
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:193)
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:430)
Caused by: java.net.ConnectException: Verbindungsaufbau abgelehnt (Connection refused)
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at org.postgresql.core.PGStream.<init>(PGStream.java:62)
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:144)
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:194
)
The server cannot reach out to the database even though it is available now. If I restart the server the database will be found and can be worked with, but the database lways has to be there on startup. How can I fix that, so that the app can be started independently of the database?
If the database becomes unavailable after the application has started it is no problem after the db becomes available again. it is automatically reconnected.
Any help is greatly apreciated!

It seems like you are leaving some connections open to Postgres. These connections must be closed or else Postgres will hit its max_connections limit.
You could increase max_connections but it's not recommended as performance of Postgres will degrade if it's set too high. Also, as you are using HikariCP it wouldn't be a bad idea to take a look at the HikariCP docs, in particular the idleTimeout and the minimumIdle config variables should help you.
If the above doesn't work then you must confirm exactly how many connections are being made to Postgres. Maybe even check the number of sessions you personally are making to Postgres via SSH or through other apps, not just the number of Play Framework connections.

Connection to Oracle 11g from network machine fails via java

I have orace 11g running on 192.168.1.217 and I am trying to connect it using JDBC driver with java and it gives me following error
IO Error: The Network Adapter could not establish the connection
Library I am using is ojdbc6.jar
Here is my code
public void makeOracleConnection() {
try {
Class.forName("oracle.jdbc.OracleDriver");
oraCon = DriverManager.getConnection("jdbc:oracle:thin:#192.168.1.217:1521:orcl", "hr", "hr");
oraStmt = oraCon.createStatement();
oraRsStmt=oraCon.createStatement(ResultSet.CONCUR_READ_ONLY,ResultSet.TYPE_SCROLL_INSENSITIVE);
} catch (Exception e) {
System.out.println("Error while making connection with Database : " + e.getMessage());
}
}
I have also tried to ping on 192.168.1.217 then pins is successful.
Also TNSLISTENER is running on that machine.
please help.
Please find print stack trace here
run:
java.sql.SQLRecoverableException: IO Error: The Network Adapter could not establish the connection
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:743)
at oracle.jdbc.driver.PhysicalConnection.connect(PhysicalConnection.java:657)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:560)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:247)
at test.oracle.makeOracleConnection(oracle.java:30)
at test.oracle.<init>(oracle.java:21)
at test.oracle.main(oracle.java:69)
Caused by: oracle.net.ns.NetException: The Network Adapter could not establish the connection
at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:470)
at oracle.net.resolver.AddrResolution.resolveAndExecute(AddrResolution.java:506)
at oracle.net.ns.NSProtocol.establishConnection(NSProtocol.java:595)
at oracle.net.ns.NSProtocol.connect(NSProtocol.java:230)
at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1452)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:496)
... 8 more
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:163)
at oracle.net.nt.ConnOption.connect(ConnOption.java:159)
at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:428)
... 13 more
BUILD SUCCESSFUL (total time: 1 second)

You get the error
java.net.ConnectException: Connection refused: connect
Which means that there is nothing listening on the machine and port you are trying to connect to. Your Java code looks correct so I would continue to investigate that Oracle is actually listening on port 1521 on 192.168.1.217.
If you run run netstat -n on the server you should find a line that looks like
TCP [::]:1521 [::]:0 LISTENING
If something really is listening on that port. If you do not find that line, check your Oracle configuration.

Try to connect with some other tool, ie sqlplus to verify that the issue is not with Oracle. If you cannot connect with sqlplus/sql developer, make sure that your oracle is configured to allow remote connections, and also listens on given addresses/ports

public void makeOracleConnection() {
try {
Class.forName("oracle.jdbc.OracleDriver");
Connection oraCon = DriverManager.getConnection("jdbc:oracle:thin:#192.168.1.217:1521:orcl", "hr", "hr");
Statement oraStmt = oraCon.createStatement();
//oraRsStmt=oraCon.createStatement(ResultSet.CONCUR_READ_ONLY,ResultSet.TYPE_SCROLL_INSENSITIVE);
ResultSet rs = oraStmt.executeQuery("select hello as result from dual");
while(rs.next()) {
System.out.println(rs.getString("result"));
}
}
catch (Exception e)
System.out.println("Error while making connection with Database : " + e.getMessage());
}
}
Try this out. Hope it'll help. I also don't like your connection path. Is it right? I think it should be something like this:
jdbc:oracle:thin:#(DESCRIPTION=(ADDRESS_LIST=(LOAD_BALANCE=YES)(ADDRESS=(PROTOCOL=tcp)(HOST=ip adres)(PORT=port)))(CONNECT_DATA=(SERVICE_NAME = orcl)))","username","password"

String out of index with SQL developer

I got below message from sql developer when I try to access.
I did just nothing special.
my connection info like below
Connection name : z*sch***
Username : root
Password : it just numbers and characters(en)
Connect Type : basic
Role : default
Host name : IP4 type address
Port : 3306(MySQL)
SID : z*_*
Sorry for '*', But I sure that I opened information that I can do. There is no long Strings, so I do not know why this program(SQLDeveloper) shows error message 'String out of range'. Give me the light! :D
java.lang.StringIndexOutOfBoundsException: String index out of range: 13113
at java.lang.String.checkBounds(String.java:401)
at java.lang.String.<init>(String.java:338)
at oracle.net.ns.Packet.extractData(Packet.java:439)
at oracle.net.ns.RefusePacket.<init>(RefusePacket.java:72)
at oracle.net.ns.NSProtocol.connect(NSProtocol.java:356)
at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1126)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:337)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:552)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:253)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:526)
at oracle.jdeveloper.db.adapter.AbstractConnectionCreator.getConnection(AbstractConnectionCreator.java:153)
at oracle.dbtools.raptor.standalone.connection.RaptorConnectionCreator.getConnection(RaptorConnectionCreator.java:195)
at oracle.dbtools.raptor.dialogs.conn.ConnectionPrompt.promptForPassword(ConnectionPrompt.java:67)
at oracle.jdeveloper.db.adapter.DatabaseProvider.getConnection(DatabaseProvider.java:321)
at oracle.jdeveloper.db.adapter.DatabaseProvider.getConnection(DatabaseProvider.java:254)
at oracle.jdevimpl.db.adapter.CADatabaseFactory.createConnectionImpl(CADatabaseFactory.java:60)
at oracle.javatools.db.DatabaseFactory.createConnection(DatabaseFactory.java:534)
at oracle.javatools.db.DatabaseFactory.createDatabase(DatabaseFactory.java:208)
at oracle.jdeveloper.db.DatabaseConnections.getDatabase(DatabaseConnections.java:607)
at oracle.dbtools.raptor.utils.Connections$ConnectionInfo.getDatabase(Connections.java:172)
at oracle.dbtools.raptor.utils.Connections.getConnection(Connections.java:1064)
at oracle.dbtools.raptor.utils.Connections.getConnection(Connections.java:1045)
at oracle.dbtools.raptor.navigator.DatabaseConnection.openConnectionImpl(DatabaseConnection.java:115)
at oracle.dbtools.raptor.navigator.AbstractConnectionNode.getConnection(AbstractConnectionNode.java:30)
at oracle.dbtools.raptor.navigator.ConnectionFilter.getFactory(ConnectionFilter.java:94)
at oracle.dbtools.raptor.navigator.ConnectionFilter$1.doWork(ConnectionFilter.java:119)
at oracle.dbtools.raptor.navigator.ConnectionFilter$1.doWork(ConnectionFilter.java:104)
at oracle.dbtools.raptor.backgroundTask.RaptorTask.call(RaptorTask.java:193)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at oracle.dbtools.raptor.backgroundTask.RaptorTaskManager$RaptorFutureTask.run(RaptorTaskManager.java:515)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:439)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
at java.lang.Thread.run(Thread.java:695)

I am sure you have solved this issue, but since I faced this issue and found the solution, I am posting it here so that it might help someone.
I got this error while trying to connect to mysql db via sql developer using the oracle db connection tab.
SOlution - Loaded the mysql-jdbc jar in sql developer(tools-preference-database-third party jdbc drivers) and when connecting to the sql developer database I selected the my sql tab (appears next to oracle tab in new connection wizard window).
Version of sqldev - 4.0.2.15

I found one more solution for the subjected error.
The database I was trying to connect was located on other server. When I did telnet via putty to that linux/AIX server issue was resolved.