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praveen p kumar

Joined: Oct 24, 2000
Posts: 3
Hi All,
I am getting below exception while trying to connect ORACLE database using jdbc racle:thin driver:
Exception in thread "main" java.sql.SQLException: Io exception: The Network Adap
ter could not establish the connection
at oracle.jdbc.dbaccess.DBError.throwSqlException(
at oracle.jdbc.dbaccess.DBError.throwSqlException(
at oracle.jdbc.dbaccess.DBError.throwSqlException(
at oracle.jdbc.driver.OracleConnection.<init>(
at oracle.jdbc.driver.OracleDriver.getConnectionInstance(OracleDriver.ja
at oracle.jdbc.driver.OracleDriver.connect(
at java.sql.DriverManager.getConnection(Compiled Code)
at java.sql.DriverManager.getConnection(
at Employee1.main(Compiled Code)

If anyone can give me reason for the above exception. It would be a great help to me.
Praveen Kumar
Ranch Hand

Joined: Nov 22, 2008
Posts: 18944
I have had a similar problem. What I did first was verify that I could connect to Oracle. We use TNS names so I went to a DOS prompt and entered TNSPING <dbinstance> to verify the database connection properties. I then wrote down the hostname from here and the port.
To double check that my computer could connect to Oracle, I used sqlplus to verify my connection. If you cannot connect to Oracle via SQLPlus, maybe you have other restrictions you are not aware of (firewall, listener problem, etc).
I am using the JDBC thin-client from Oracle ( and here is an example. I read from a flat-file to get the setting information so the connection information is not hardcoded:

private String determineJDBCDriver(){
String whichJDBC = getRunProperty("WhichJDBC");
String jdbcDriver = getRunProperty((whichJDBC+"JDBC"));
//new oracle.jdbc.driver.OracleDriver()
addTrace("Driver "+jdbcDriver+" is now registered");
} catch (SQLException sqle){
addTrace("A SQL Exception occurred -> "+sqle);
return null;
} catch (ClassNotFoundException cnfe){
addTrace("JDBC Driver "+jdbcDriver+" not found -->"+cnfe);
return null;
} catch (Exception e){
addTrace("An Exception occurred while setting JDBC Driver -> "+e);
return null;
String getUrl = whichJDBC+"URL";
if(getUrl != null)
addTrace("Getting JDBC URL with -> "+getUrl);
return getRunProperty(getUrl);

public boolean authenticateUser()
String jdbcConnection = determineJDBCDriver();//getRunProperty("JDBCConnection");
return false;
} else {
addTrace("Received JDBC URL -> "+jdbcConnection);
String user=getRunProperty("DefaultUser");
String pass=getRunProperty("DefaultPassword");

addTrace("JDBC -> "+jdbcConnection+" and USER -> "+user+" and PASS -> "+pass);
java.sql.Connection jdbcConn =

String sSQL = "SELECT ORACLE_USERNAME FROM SEC_USER WHERE UPPER(ORACLE_USERNAME) ='" + getLogin().trim().toUpperCase() + "'";
addTrace("authenticateUser theSQL->" + sSQL);

Statement stmt = jdbcConn.createStatement();
boolean value = false;
java.sql.ResultSet rset = stmt.executeQuery(sSQL);
//addTrace("Found User ->"+rset.getString(1));
value = true;
return value;
} catch (Exception e){
addTrace("User "+getLogin().trim()+" not found");
return false;
}catch(Exception ex){
addTrace("Error in authenticateUser "+ex.toString());
return false;
I agree. Here's the link:
subject: JDBC- ORACLE
It's not a secret anymore!