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Java exception connecting to MySQL

SOLVED
The latest version of MySQL JDBC driver evidently attempts to create an SSL connection. The app which WORKED did NOT define javax.net.ssl.keystore (and other) values, so (I assume) it reverts to a non-SSL connection. The app which FAILED did define all of the keystore/certificate parameters and then the connection attempt failed - still not sure of exactly why, if someone could enlighten would appreciate. The exception thrown could also be more informative.
Anyway, adding "&useSSL=false&allowPublicKeyRetrieval=true" to the connection parameters works for both applications. (Although not a very good setup for any production app, can use for this POC!)
============= Original Posting Follows =========
This has had me stumped for a few days! AWS server (86_64), Fedora 29, Java 8 (1.8.0_201-b09), MySQL - all upgraded to the latest release. MySQL is running on the same server. Driver: com.mysql.cj.jdbc.Driver
Connection params: jdbc:mysql://172.31.10.222:3306?user=xxxx&password=xxxx. (IP is the AWS private IP for this server.)
Have 2 different utilities - separate 'main' routines, but all in the same JAR file. The first one works perfectly, the second one aborts with the stack pasted below. This is consistent over dozens of trials with minor variations.
The different main routines both use the 'connectToDB' method shown in the stack trace. Instrumented this to log all parameters and the class name of the driver in both cases and verified that they are identical.
Have already tried/verified:
Multiple Google searches of the same error
MySql is running and OK (connect thru another terminal window w no problem),
Same JAR used with all local code
Classpath is identical
Running under the same Linux user, using the same MySQL user/password
Verified the IP above (172.31.10.222)
Also changed the IP to 'localhost', 127.0.0.1, and a symbolic name from /etc/hosts
Added -Xmx2G to make sure not an OOM issue
These are 2 different 'main' methods, but don't do much more than load some properties (from the same property files) before trying to connect to the DB. Then they execute the same connectToDB routine.
Something in the context must be different! Hoping that someone here can at least provide some hints on where to look!
Thanks
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:835)
at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:455)
at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)
at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:207)
at spc.tools.spcConnection.connectToDB(spcConnection.java:692)
at spc.tools.spcConnection.connectToLocalDB(spcConnection.java:1418)
at spc.tools.spcConnection.loadAllConnectionsOK(spcConnection.java:1112)
at spc.tools.spcConnection.initOneTime(spcConnection.java:1012)
at spc.tools.spcConnection.init(spcConnection.java:194)
at spc.ops.spcServerBase.environmentOK(spcServerBase.java:367)
at spc.ops.spcServerBase.environmentOK(spcServerBase.java:342)
at spc.run.daemon.spcDaemon.main(spcDaemon.java:1082)
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
at com.mysql.cj.protocol.a.NativeProtocol.negotiateSSLConnection(NativeProtocol.java:351)
at com.mysql.cj.protocol.a.NativeAuthenticationProvider.negotiateSSLConnection(NativeAuthenticationProvider.java:777)
at com.mysql.cj.protocol.a.NativeAuthenticationProvider.proceedHandshakeWithPluggableAuthentication(NativeAuthenticationProvider.java:486)
at com.mysql.cj.protocol.a.NativeAuthenticationProvider.connect(NativeAuthenticationProvider.java:202)
at com.mysql.cj.protocol.a.NativeProtocol.connect(NativeProtocol.java:1442)
at com.mysql.cj.NativeSession.connect(NativeSession.java:165)
at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:955)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825)
... 11 more
Caused by: java.net.SocketException: Broken pipe (Write failed)
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:111)
at java.net.SocketOutputStream.write(SocketOutputStream.java:155)
at sun.security.ssl.OutputRecord.writeBuffer(OutputRecord.java:431)
at sun.security.ssl.OutputRecord.write(OutputRecord.java:417)
at sun.security.ssl.SSLSocketImpl.writeRecordInternal(SSLSocketImpl.java:879)
at sun.security.ssl.SSLSocketImpl.writeRecord(SSLSocketImpl.java:850)
at sun.security.ssl.SSLSocketImpl.writeRecord(SSLSocketImpl.java:720)
at sun.security.ssl.Handshaker.sendChangeCipherSpec(Handshaker.java:1144)
at sun.security.ssl.ClientHandshaker.sendChangeCipherAndFinish(ClientHandshaker.java:1280)
at sun.security.ssl.ClientHandshaker.serverHelloDone(ClientHandshaker.java:1190)
at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:369)
at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1037)
at sun.security.ssl.Handshaker.process_record(Handshaker.java:965)
at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1064)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1367)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1395)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1379)
at com.mysql.cj.protocol.ExportControlled.performTlsHandshake(ExportControlled.java:315)
====================================================== New Information =====
Here are the key lines from the connectToDB method (responding to comment below):
Driver dvr = (Driver)Class.forName(info.sDBDriver).newInstance();
if(dvr!=null) conn = dvr.connect(accessString(), null);
verified the expected driver and that accessString() returns the 'jdbc:mysql:...' string as above. The exception is thrown executing the 2nd line above.
Since the original post, put in code to run a 'netstat -ln' immediately before these lines and post the result to the log. This shows an active listener for port 3306.

It would be great if you can post connectToDB() method.
According to this sentence " The first one works perfectly, the second one aborts with the stack pasted below.", you must have closed the db connection in the first connectToDB() call.
So that second call is broken as the DB connection was terminated by first call.
The good way to setup is to use dependency injection for database object.
Hope this helps!

failure to connect to mysql from java locally while remote connection works

I have the following situation:
I can
connect to my mysql database via the command line tool mysql, both from the local machine and a remote host
connect from a small java test program from the remote host
I can not
connect from that same small java test program from the local machine
The test code is basically the same as in this question and I followed all the suggestions given there to solve my problem with no avail. I have tried the following connection strings:
jdbc:mysql://localhost/database
jdbc:mysql://localhost:3306/database
jdbc:mysql://127.0.0.1/database
jdbc:mysql://hostname/database
all resulting in the same error message. On the remote machine I could use the fourth alternative with no problem.
I am running a mysql-5.5 server. The remote uses java version "1.7.0_101" and the local machine has java version "1.6.0_38".
Here is the error message when I run my java program on the local machine:
Connecting to database...
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago.
The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:534)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1116)
at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:688)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1094)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2337)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2370)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2154)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:792)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:534)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:381)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305)
at java.sql.DriverManager.getConnection(DriverManager.java:615)
at java.sql.DriverManager.getConnection(DriverManager.java:195)
at FirstExample.main(FirstExample.java:22)
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2540)
at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:612)
... 16 more
Goodbye!

I just realized that mysql -u user database would work, but not mysql -u user -h 127.0.0.1 database, so it turned out I had an error in my /etc/hosts.allow file. Problem solved!

Connect to the MySQL server from another PC (from java application)

I realized an java application that connects to MySQL.
when i make my ip adress of my pc in the navigator of another pc in same local network ,I access to phpMyadmin and Wamp.
When i make 127.0.0.1 on the same pc (Wamp install) I connect to 127.0.0.1 from my java application and it works .
but the problem when I put my ip address in my java application either from my pc or from another pc in same local network , I can not manage to connect .
this is my file of configuration in the java application:
db.user=root
db.password=
db.driver=com.mysql.jdbc.Driver
db.url=jdbc:mysql://192.168.1.59:3306/testfournisseur
Is there a manipulation to do?
This is the errors appear when i connect to the database:
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
Last packet sent to the server was 1 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.MysqlIO.readPacket(MysqlIO.java:666)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1069)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2031)
... 72 more
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2431)
at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:590)
... 74 more

I'm unfamiliar with MySQL on Windows but the most common reason I see for being unable to connect is that the bind-address in my.cnf is set to 127.0.0.1, if you change this to 0.0.0.0 or another accessible address then it should work fine.
I also noticed you specify port 80 in your properties example, MySQL runs on 3306 by default so changing the port to that (or omitting it) may work.
Edit: Windows' built-in firewall may be blocking the connection so it's definitely worth checking out.

Could not open JPA EntityManager for transaction; nested exception is javax.persistence.PersistenceException

when i run my code, i get this exception:
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:357)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2482)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2519)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2304)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:346)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:208)
at org.springframework.jdbc.datasource.DriverManagerDataSource.getConnectionFromDriverManager(DriverManagerDataSource.java:153)
at org.springframework.jdbc.datasource.DriverManagerDataSource.getConnectionFromDriver(DriverManagerDataSource.java:144)
at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnectionFromDriver(AbstractDriverBasedDataSource.java:155)
at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnection(AbstractDriverBasedDataSource.java:120)
at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:139)
at org.hibernate.tool.hbm2ddl.SuppliedConnectionProviderConnectionHelper.prepare(SuppliedConnectionProviderConnectionHelper.java:51)
at org.hibernate.tool.hbm2ddl.DatabaseExporter.<init>(DatabaseExporter.java:52)
at org.hibernate.tool.hbm2ddl.SchemaExport.execute(SchemaExport.java:367)
at org.hibernate.tool.hbm2ddl.SchemaExport.create(SchemaExport.java:304)
at org.hibernate.tool.hbm2ddl.SchemaExport.create(SchemaExport.java:293)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:517)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1857)
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
Aug 25, 2015 8:23:45 PM com.sun.jersey.spi.container.ContainerResponse mapMappableContainerException
SCHWERWIEGEND: The RuntimeException could not be mapped to a response, re-throwing to the HTTP container
org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: Could not open connection
at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:431)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:373)
at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:457)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:276)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
at com.sun.proxy.$Proxy76.create(Unknown Source)
I don't know where is the problem. But yesterday i worked fine.
my database.properties:
jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/streaming
jdbc.username=root
jdbc.password=password
hibernate.dialect=org.hibernate.dialect.MySQLDialect
hibernate.showsql=true
hibernate.hbm2ddl.auto=create
It is possible for me to run mysql directly from command line. Where is the problem? Was is wrong.
I use spring 4 and hibernate with mysql as database language.
Has someone any ideas?
Thank.

There is CommunicationsException: Communications link failure.
If you get a SQLException: Connection refused or Connection timed out or a MySQL specific
CommunicationsException: Communications link failure
then it means that the DB isn't reachable at all. This can have one or more of the following causes:
IP address or hostname in JDBC URL is wrong.
Hostname in JDBC URL is not recognized by local DNS server.
Port number is missing or wrong in JDBC URL.
DB server is down.
DB server doesn't accept TCP/IP connections.
DB server has run out of connections.
Something in between Java and DB is blocking connections, e.g. a firewall or proxy.
To solve the one or the other, follow the following advices:
Verify and test them with ping.
Refresh DNS or use IP address in JDBC URL instead.
Verify it based on my.cnf of MySQL DB.
Start the DB.
Verify if mysqld is started without the --skip-networking option.
Restart the DB and fix your code accordingly that it closes connections in finally.
Disable firewall and/or configure firewall/proxy to allow/forward the port.
Source: More Details

I see that #Amit Tamrakar have good answer but I want to add:
if you make a lot of requests to db, (I mean connections), may be that application (some app thread) just wait for use free connection from app db connection pool, but throws timeout exception.
.h.engine.jdbc.spi.SqlExceptionHelper : HikariPool-1 - Connection is not available, request timed out after 30005ms.
Could not open JPA EntityManager for transaction; nested exception is org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection
You can try to increase db connection pool in application config file, for example:
spring.datasource.hikari.maximum-pool-size=20
You can set size which you need. This config in app by default is 8.
And we need remember that each db have own free db connection size which we don't need exceed.
I mean if db have 5 free connection and you want to use 10 connections in your app then we will receive so exceptions.

DB is down.
You must start the DB server and check connectivity with either telnet or mysql command line client first.

I was not unable to figure out the exact cause, but I realized that it was because of some thread pools since I was able to connect to the db using the terminal.
for checking the connectivity you can use the below command.
psql -h hostname -U username -d database
so restarting the server worked for me.

Remote Database

I tried creating an app in java that works with a remote database. The apps works fine on a local database. I have included the the port number as well. I am scared that it may be the IP address I am using.
I thought to myself there may be hundreds if not thousands of pc's around the world with the same IP as mine... and how does the Internet see which one I am, or stay secure about it. I am sure you don't give the remote access the IP of you computer of you home network, but I may be wrong... I honestly don't know.
This is my function.
public void db() {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection myCon = DriverManager.getConnection("jdbc:mysql://IPOfWebSite:3306/DatabaseName", "UserName", "Password");
System.out.println("Connected");
myCon.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
On the Remote DB I have added my public IP address, but still received this error
"C:\Program Files\Java\jdk1.8.0_25\bin\java" -Didea.launcher.port=7532 "-Didea.launcher.bin.path=C:\Program Files (x86)\JetBrains\IntelliJ IDEA Community Edition 14.1.3\bin" -Dfile.encoding=windows-1252 -classpath "C:\Program Files\Java\jdk1.8.0_25\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\rt.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\zipfs.jar;H:\Java Dev\Simple_java_DB\out\production\Simple_java_DB;H:\Java Dev\Simple_java_DB\mysql-connector-java-5.1.35\mysql-connector-java-5.1.35\mysql-connector-java-5.1.35-bin.jar;C:\Program Files (x86)\JetBrains\IntelliJ IDEA Community Edition 14.1.3\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain Main
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:389)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1038)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:338)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2237)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2270)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2069)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:794)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:389)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:399)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:325)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:247)
at Main.db(Main.java:24)
at Main.main(Main.java:15)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:345)
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 com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:213)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:297)
... 21 more
Any help will be great. By the way I did check my firewall... it should allow the port to receive and sent.

MySQL does by default only listen to the local interface (loopback). So you can only reach it from the local machine.
To change this, adapt the MySQL conf:
[mysqld]
bind-address=YOUR-SERVER-IP
Also, make sure the skip-networking configuration is commented out or not present.
More details here.

1) Make sure you're adding your external IP, not your internal network IP (192.168.x.x).
Go to: https://www.whatismyip.com/ and use that IP for whitelisting your IP in the remote DB's firewall and/or access restrictions.
2) Make sure your mysql user is set up with the correct host, either 'user'#'your-external-ip' or 'user'#'%' (to allow that user to connect from any IP).
3) Make sure your my.conf is set up to allow remote connections. Make sure you're not binding to 127.0.0.1, instead temporarily do:
bind-address = 0.0.0.0;
You should set this to your server's actual IP, but 0.0.0.0 will work for any IP and should just be used temporarily to verify that this is your problem. Long term it could pose a security risk to leave it as 0.0.0.0.
Also make sure that you're not skipping networking. Make sure this line is commented out (with a # in front of it):
# skip-networking