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POConnection to Oracle from Java unreliable
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  1. POConnection to Oracle from Java unreliable
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    copied!<p>I'm new to Java and trying to setup a connection to an Oracle database from a redhat Linux machine. I've got the connection working and can execute a simple sql script but the connection only works approx. 1 in 3 times. The error it gives and the code is below. It is quite possible this is an issue with our network but I would like to have a bit more knowledge before I raise a support case. Does anyone know why the error says "Name or service not known" for ssdb0255n21-oravip when "someserver" is what is specified in the connection?</p> <pre><code>Exception in thread "main" java.sql.SQLRecoverableException: IO Error: The Network Adapter could not establish the connection at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:673) at oracle.jdbc.driver.PhysicalConnection.&lt;init&gt;(PhysicalConnection.java:715) at oracle.jdbc.driver.T4CConnection.&lt;init&gt;(T4CConnection.java:385) at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:30) at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:564) at java.sql.DriverManager.getConnection(DriverManager.java:571) at java.sql.DriverManager.getConnection(DriverManager.java:187) at OracleTest.main(OracleTest.java:19) Caused by: oracle.net.ns.NetException: The Network Adapter could not establish the connection at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:445) at oracle.net.resolver.AddrResolution.resolveAndExecute(AddrResolution.java:464) at oracle.net.ns.NSProtocol.establishConnection(NSProtocol.java:594) at oracle.net.ns.NSProtocolStream.negotiateConnection(NSProtocolStream.java:214) at oracle.net.ns.NSProtocol.connect(NSProtocol.java:263) at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1360) at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:486) ... 7 more Caused by: java.net.UnknownHostException: ssdb0255n21-oravip: Name or service not known at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method) at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:894) at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1286) at java.net.InetAddress.getAllByName0(InetAddress.java:1239) at java.net.InetAddress.getAllByName(InetAddress.java:1155) at java.net.InetAddress.getAllByName(InetAddress.java:1091) at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:117) at oracle.net.nt.ConnOption.connect(ConnOption.java:133) at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:411) ... 13 more </code></pre> <p>The code I am using is this</p> <pre><code>import java.sql.*; import java.util.Properties; public class OracleTest { public static void main(String[] args) throws SQLException { String url = "jdbc:oracle:thin:@ldaps://someserver:3131/ODBF2_BLOOD_P_S_B_001,cn=OracleContext,dc=in,dc=companyname,dc=com,dc=au"; //properties for creating connection to Oracle database Properties props = new Properties(); props.setProperty("user", "xxx"); props.setProperty("password", "xxxx"); //creating connection to Oracle database using JDBC System.out.println(DriverManager.getLoginTimeout()); Connection conn = DriverManager.getConnection(url,props); String sql ="select sysdate as current_day from dual"; //creating PreparedStatement object to execute query PreparedStatement preStatement = conn.prepareStatement(sql); ResultSet result = preStatement.executeQuery(); while(result.next()) { System.out.println("Current Date from Oracle : " + result.getString("current_day")); } System.out.println("done"); } } </code></pre> <p>I have ORACLE_HOME set to /usr/lib/oracle/10.2.0.5/client64/ and have created ldap.ora and sqlnet.ora files in /usr/lib/oracle/10.2.0.5/client64/network/admin. Contents of these are:</p> <p>sqlnet.ora</p> <pre><code>NAMES.DIRECTORY_PATH = (LDAP,TNSNAMES) </code></pre> <p>ldap.ora</p> <pre><code>DIRECTORY_SERVERS = (OID.GLB.IN.companyname.COM.AU::3131) DEFAULT_ADMIN_CONTEXT = "dc=in,dc=companyname,dc=com,dc=au" DIRECTORY_SERVER_TYPE = OID </code></pre> <p>It appears to have created tnsnames.ora itself</p> <pre><code>ORA11 = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521)) ) (CONNECT_DATA = (SERVICE_NAME = ORA11) ) ) </code></pre>
 

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