com.mysql.jdbc.exceptions.jdbc4.CommunicationsException

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tip

Firewall might be blocking your connection, or MySQL it's not running on your server machine.


rafael
tip

Check if you have started your server, or if your server is set to listen to the port you're trying to connect and is waiting to accept connections and check if the firewall isn't blocking your connection.


rafael
tip

Check if ip adress is correct, if the port is correct, and if the server is up and running and waiting for connections. Also, check if there's no firewall blocking you and if your internet connection is working.


rafael

You have a different solution? A short tip here would help you and many other users who saw this issue last week.

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    • com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure Last packet sent to the server was 0 ms ago. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source) at com.mysql.jdbc.Util.handleNewInstance(Util.java:406) at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074) at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2104) at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:729) at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source) at com.mysql.jdbc.Util.handleNewInstance(Util.java:406) at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:302) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:283) at java.sql.DriverManager.getConnection(Unknown Source) at java.sql.DriverManager.getConnection(Unknown Source) at UserAuthPubKey.connectToDB(UserAuthPubKey.java:72) at UserAuthPubKey.main(UserAuthPubKey.java:44) Caused by: java.net.ConnectException: Connection refused: connect at java.net.DualStackPlainSocketImpl.connect0(Native Method) at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source) at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source) at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source) at java.net.AbstractPlainSocketImpl.connect(Unknown Source) at java.net.PlainSocketImpl.connect(Unknown Source)

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