Does anyone know how to fix it? Thanks

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet successfully received from the server was 32,432 milliseconds ago.  The last packet sent successfully to the server was 0 milliseconds ago.
	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:1117)
	at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3567)
	at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3456)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3997)
	at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2468)
	at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2629)
	at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2719)
	at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
	at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:1379)
	at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
	at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:172)
	at services.totalonline.totalonline$updateOnline.run(totalonline.java:50)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
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:3017)
	at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3467)
	... 17 more

 

connection was unexpectedly lost

If MySQL is running on a remote server, that would mean there are some connectivity issues. Yeah, connections can end up dropped. Select another remote server and hope for the best. Alternatively, check that the RJ45 port locks the cable in properly on both machines.

 

If this happens when both servers are running on the same machine, there's plenty of things that can be happening. First, check your memory (both that you cannot run out of it and that the physical memory components (RAM and disk drive(s) with swap/page file(s)) are functioning properly.

Then, check for resource exhaustion: perhaps you have spec'd 1k/10k/100k connections in MySQL properties? Stupid typos like this can cause exhaustion related issues.

Things like this can also happen if you are running some torrent app that keeps allocating sockets (even though they are left half-open), etc.

http://www.supermanhamuerto.com/doku.php?id=java:thelastpacketsuccessfullyreceivedfromserver

 

The 2 common errors and another one.

thanks :) , i fix them :)

Edited October 8, 201511 yr by petr.plasan

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Locked.