title: The network adapter could not establish the connection - Oracle 11g
body: <p>I wrote a servlet program and I want it to connect to my Oracle database but its giving me an error. I am using Eclipse Helios, Tomcat 6.0.37, Oracle 11g (11.2.0.1.0), ojdbc6.jar(added in run configuration of the Server project). I am able to connect to the database through the SQL Plus interface and even can start a connection from Eclipse's database development perspective. But when i am trying to connect through my servlet I am getting the error. For my servlet i am using the port number 9090 and for the database the default 1521.</p>
  
  <pre><code>java.sql.SQLException: The Network Adapter could not establish the connection
      at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:412)
      at oracle.jdbc.driver.PhysicalConnection.&lt;init&gt;(PhysicalConnection.java:531)
      at oracle.jdbc.driver.T4CConnection.&lt;init&gt;(T4CConnection.java:221)
      at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
      at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:503)
      at java.sql.DriverManager.getConnection(Unknown Source)
      at java.sql.DriverManager.getConnection(Unknown Source)
      at com.android.collegenotificationsystem.RegistrationServlet.doGet(RegistrationServlet.java:43)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
      at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:861)
      at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:606)
      at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
      at java.lang.Thread.run(Unknown Source)
  Caused by: oracle.net.ns.NetException: The Network Adapter could not establish the connection
      at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:359)
      at oracle.net.resolver.AddrResolution.resolveAndExecute(AddrResolution.java:422)
      at oracle.net.ns.NSProtocol.establishConnection(NSProtocol.java:672)
      at oracle.net.ns.NSProtocol.connect(NSProtocol.java:237)
      at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1042)
      at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:301)
      ... 21 more
  Caused by: java.net.ConnectException: Connection refused: connect
      at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
      at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
      at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
      at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
      at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
      at java.net.PlainSocketImpl.connect(Unknown Source)
      at java.net.SocksSocketImpl.connect(Unknown Source)
      at java.net.Socket.connect(Unknown Source)
      at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:141)
      at oracle.net.nt.ConnOption.connect(ConnOption.java:123)
      at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:337)
      ... 26 more
  </code></pre>
  
  <p>This is my code for establishing the connection:</p>
  
  <p><code>Class.forName("oracle.jdbc.OracleDriver");
      Connection con = (Connection) DriverManager.getConnection(                  "jdbc:oracle:thin:@localhost:1521:orcl","username","password");</code> </p>
  
  <p>I tried executing the lsnrctl stat command and this was the result:</p>
  
  <pre><code>LSNRCTL for 32-bit Windows: Version 11.2.0.1.0 - Production on 03-AUG-2013 16:08
  :46
  
  Copyright (c) 1991, 2010, Oracle.  All rights reserved.
  
  Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1521)))
  STATUS of the LISTENER
  ------------------------
  Alias                     LISTENER
  Version                   TNSLSNR for 32-bit Windows: Version 11.2.0.1.0 - Produ
  ction
  Start Date                03-AUG-2013 12:14:19
  Uptime                    0 days 3 hr. 54 min. 28 sec
  Trace Level               off
  Security                  ON: Local OS Authentication
  SNMP                      OFF
  Listener Parameter File   C:\app\Owner\product\11.2.0\dbhome_1\network\admin\lis
  tener.ora
  Listener Log File         c:\app\owner\diag\tnslsnr\Owner-PC\listener\alert\log.
  xml
  Listening Endpoints Summary...
    (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\EXTPROC1521ipc)))
    (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=1521)))
  Services Summary...
  Service "CLRExtProc" has 1 instance(s).
    Instance "CLRExtProc", status UNKNOWN, has 1 handler(s) for this service...
  Service "orcl.168.1.56" has 1 instance(s).
    Instance "orcl", status READY, has 1 handler(s) for this service...
  Service "orclXDB.168.1.56" has 1 instance(s).
    Instance "orcl", status READY, has 1 handler(s) for this service...
  The command completed successfully
  </code></pre>
  
  <p>These are the contents of my tnsnames.ora file:</p>
  
  <pre><code>LISTENER_ORCL =
    (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
  
  
  ORACLR_CONNECTION_DATA =
    (DESCRIPTION =
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
      )
      (CONNECT_DATA =
        (SID = CLRExtProc)
        (PRESENTATION = RO)
      )
    )
  
  ORCL =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
      (CONNECT_DATA =
        (SERVER = DEDICATED)
        (SERVICE_NAME = orcl.168.1.56)
      )
    )
  </code></pre>
  
  <p>Any help would be appreciated. Thanks in advance.</p>