"java.sql.SQLException: I/O Error: Connection reset" in linux server

Question

I have a java program which connect to oracle database sometimes it work and sometimes show me this error message :

Exception in thread "main" java.sql.SQLRecoverableException: IO Error: Connection reset

at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:498)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:553)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:254)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:528)

How i can solve this problem?

Karim · Answer 1 · 2018-07-16T17:49:31.197

7

Answer took from oracle forum, here:

java.security.SecureRandom is a standard API provided by sun. Among various methods offered by this class void nextBytes(byte[]).

This method is used for generating random bytes. Oracle 11g JDBC drivers use this API to generate random number during login. Users using Linux have been encountering SQLException("Io exception: Connection reset").

The problem is two fold:

The JVM tries to list all the files in the /tmp (or alternate tmp directory set by -Djava.io.tmpdir) when SecureRandom.nextBytes(byte[]) is invoked. If the number of files is large the method takes a long time to respond and hence cause the server to timeout
The method void nextBytes(byte[]) uses /dev/random on Linux and on some machines which lack the random number generating hardware the operation slows down to the extent of bringing the whole login process to a halt. Ultimately the the user encounters SQLException("Io exception: Connection reset")

Users upgrading to 11g can encounter this issue if the underlying OS is Linux which is running on a faulty hardware.

The cause of this has not yet been determined exactly. It could either be a problem in the hardware or the fact that for some reason the software cannot read from dev/random

a solution seems to add this setting to the jvm

-Djava.security.egd=file:/dev/./urandom

edited Jul 16 '18 at 17:49

answered May 04 '17 at 08:04

Karim

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where i can find this file? such i use linux?? – Mohamed Fenni May 04 '17 at 08:19
Please explain what the underlying issue is and why this answer would solve it? If the answer is in the links then you should consider summarising the salient points in your answer. – MT0 May 04 '17 at 08:22
i've just fixed my answer. @MohamedFenni you have to pass this setting to the jvm – Karim May 04 '17 at 08:37
i learn this two link and when i type $JAVA_HOME/jre/lib/security it show me no such directory so for this i asked where i can find this file – Mohamed Fenni May 04 '17 at 08:39
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try running your app from command line: java -Djava.security.egd=file:/dev/./urandom -jar yourAppName.jar – Karim May 04 '17 at 08:48
i run it in windows or linux?because i deploy my program to .jar and i use it in linux – Mohamed Fenni May 04 '17 at 09:06
thank you, this solved my problem but now when i execut the same program many times it take long time to be executed – Mohamed Fenni May 04 '17 at 10:03
could be the hardware issue stated above in point nr° 2. – Karim May 04 '17 at 10:21
i don't understand – Mohamed Fenni May 04 '17 at 10:23

score -1 · Answer 2 · edited May 23 '17 at 10:31

-1

Connection reset usually happens when the connection between you app and the database gets disconnected for example network issue or resources that's required.

Check the following post it should give you an idea of what to check. SQLRecoverableException: I/O Exception: Connection reset

edited May 23 '17 at 10:31

Community

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answered May 04 '17 at 08:03

Renier

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"java.sql.SQLException: I/O Error: Connection reset" in linux server

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