java.sql.SQLRecoverableException: IO Error: Connection reset by peer, Authentication lapse

This post has moved to eklausmeier.goip.de/blog/2019/01-19-java-sql-sqlrecoverableexception-io-error-connection-reset-by-peer-authentication-lapse.

I encountered the following error, when I wanted to connect to Oracle v12.2.0.1.0 database with Java 1.8.0_192-b26:

java.sql.SQLRecoverableException: IO Error: Connection reset by peer, Authentication lapse 321631 ms.

This was unexpected as the same program did run absolutely fine on another Linux machine. Program in question is

import java.sql.Connection;
import java.sql.SQLException;

import oracle.jdbc.pool.OracleDataSource;

public class OraSample1 {

        public static void main (String argv[]) {
                System.out.println("Starting...");
                try {
                        OracleDataSource ds = new OracleDataSource();
                        ds.setURL("jdbc:oracle:thin:@nuc:1521:orcl");
                        Connection conn=ds.getConnection("c##klm","klmOpRisk");
                        System.out.println("Connected");
                } catch (SQLException e) {
                        System.out.println(e);
                }
        }

}

Solution: Add the following property setting to command line

java -Djava.security.egd=file:/dev/urandom OraSample1

Also see “java.sql.SQLException: I/O Error: Connection reset” in linux server [duplicate] on Stackoverflow.

Web Interface to Oracle Database

This post has moved to eklausmeier.goip.de/blog/2019/01-11-web-interface-to-oracle-database.

I had to provide access to an Oracle database but the standard port at 1521 was hindered by company firewall and company proxy rules.

In previous times there was iSQL*Plus, but this product no longer seems to be available. I found Adminer as an alternative. It is written by Jakub Vrána. It is very easy to install: it is just one single PHP file consisting of less than 2000 lines. Originally made for MySQL/MariaDB, but it works for Oracle quite well. It provides access to tables and views, although it has problems editing PL/SQL procedures and triggers. It is termed as beta software for Oracle. Nevertheless, I found it to be very useful for Oracle.

To use one must add one file etc/php/conf.d/oci8.ini

extension=oci8.so

Make sure OCI8 is available for PHP, therefore install AUR package php-oci8. When you run php -i (equivalent to calling phpinfo()) you’ll see:

Additional .ini files parsed => /etc/php/conf.d/oci8.ini

oci8

OCI8 Support => enabled
OCI8 DTrace Support => disabled
OCI8 Version => 2.1.8
Revision => $Id: 8a26cf66ca0f9556b6376408c8f71ead69bdbcbf $
Oracle Run-time Client Library Version => 12.2.0.1.0
Oracle Compile-time Instant Client Version => 12.2

Directive => Local Value => Master Value
oci8.connection_class => no value => no value
oci8.default_prefetch => 100 => 100
oci8.events => Off => Off
oci8.max_persistent => -1 => -1
oci8.old_oci_close_semantics => Off => Off
oci8.persistent_timeout => -1 => -1
oci8.ping_interval => 60 => 60
oci8.privileged_connect => Off => Off
oci8.statement_cache_size => 20 => 20

For this you need to install Oracle instant client. In ArchLinux AUR these are the packages oracle-instantclient-basic and oracle-instantclient-sdk. The first package installs

/usr/lib/libclntsh.so

If you encounter “URI too long” error messages, then downgrade to version 4.6.3, see Adminer releases. Latest version 4.7.0 still seems to be unstable, while 4.6.3 is fine.