Checking credentials with "connection.openProxySession" method

Question

Our project has a WebLogic instance with a connection pool, which hits an Oracle database. When users authenticate, we want to verify their credentials with the database. Previously, this was done circumventing the connection pool, and opening a direct connection to the Oracle database to verify their credentials. For performance reasons, this is not ideal, since opening an Oracle connection is slow. There would be a performance benefit if we could verify a user's credentials by proxy-connecting with their username/password. However, I can't get it to work correctly.
So far, I've written the following java code to try and verify a user's credentials:
void testCreds(DataSource connectionPoolDataSource, String username, String password) throws SQLException {
  System.out.println("Testing credentials " + username + "/" + password + "...");
  Connection connection = connectionPoolDataSource.getConnection();
  try {
    OracleConnection oracleConnection = DaoUtils.getOracleConnection(connection);
    try {
      Properties paramProperties = new Properties();
      paramProperties.put(OracleConnection.PROXY_USER_NAME, username);
      paramProperties.put(OracleConnection.PROXY_USER_PASSWORD, password);
      oracleConnection.openProxySession(OracleConnection.PROXYTYPE_USER_NAME, paramProperties);
      oracleConnection.close(OracleConnection.PROXY_SESSION);
      System.out.println("Credentials are valid");
    } catch (Exception e) {
      System.out.println("Credentials are invalid " + e.getClass() + ")");
  } finally {
    connection.close();
}This works OK, until it's called with an invalid credential pair. Then, the connection is "poisoned" and won't work again, producing the following error if createStatement() is called:
Caused by: java.sql.SQLException: Closed Connection
     at oracle.jdbc.driver.SQLStateMapping.newSQLException(SQLStateMapping.java:70)
     at oracle.jdbc.driver.DatabaseError.newSQLException(DatabaseError.java:133)
     at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:199)
     at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:263)
     at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:271)
     at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:445)
     at oracle.jdbc.driver.PhysicalConnection.createStatement(PhysicalConnection.java:3006)I've tried various ways to "unpoison" the connection, such as closing the proxy session, or opening a new proxy session, but I'm out of ideas. In the meantime the best workaround I can think of is to circumvent the connection pool, and directly connect to the database, as we were doing before - but, we can proxy connect to verify a user's credentials, and if we have a problem (maybe the username/password was invalid, or the account is expired) we discard the connection and reconnect. However It seems like a hairy kludge for what should be a simple problem.
I'm running WebLogic 10.3.2, Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - 64bit Production, and Java 1.6.0_12.
Edited by: Aaron Pieper on Jun 30, 2010 12:20 PM (removed closeProxyConnection typo)

Answer 1

"Statement Cache Size" was already at zero. Enabling "Test Connections On Reserve" had a slightly positive effect, although a confusingly inconsistent one. I created a simple utility to test whether I was getting a "valid connection" from the datasource or not:
void testDataSource(DataSource ds) {
  try {
    System.out.print("Testing data source: ");
    new SimpleJdbcTemplate(ds).queryForInt("select 1 from dual");
    System.out.println("OK");
  } catch (Exception e) {
    System.out.println("BAD (" + e.getClass() + ")");
}and then tried calling it:
testDataSource(ds);
testCreds(ds, "myuser", "mypassword");
testDataSource(ds);
testDataSource(ds);This helped me test the behavior of "Test Connections On Reserve". So as long as I pass in valid credentials, it works OK. If I pass in invalid credentials, the second testDataSource() call fails, with the "closed connection" error mentioned before. "Test Connections On Reserve" doesn't help to prevent this. Surprisingly, the third testDataSource() call works OK if "Test Connections On Reserve" is on. I guess this means that the functionality works (WebLogic removes the bogus connection from the pool) but only after you call GetConnection twice.
So basically, for some reason, openProxySession poisons a connection - but not in a way that WebLogic recognizes. However, after you make a call (select 1 from dual) on that poisoned connection, it breaks the connection even more - and WebLogic removes it from the pool. With this knowledge, I can create a new version of testCreds:
void testCreds(DataSource connectionPoolDataSource, String username, String password) throws SQLException {
  Connection connection = connectionPoolDataSource.getConnection();
  System.out.println("Testing credentials " + username + "/" + password + "...");
  try {
    OracleConnection oracleConnection = DaoUtils.getOracleConnection(connection);
    try {
      Properties paramProperties = new Properties();
      paramProperties.put(OracleConnection.PROXY_USER_NAME, username);
      paramProperties.put(OracleConnection.PROXY_USER_PASSWORD, password);
      oracleConnection.openProxySession(OracleConnection.PROXYTYPE_USER_NAME, paramProperties);
      oracleConnection.close(OracleConnection.PROXY_SESSION);
      System.out.println("Credentials are valid");
    } catch (Exception e) {
      try {
        oracleConnection.createStatement().execute("");
      } catch (Exception ignored) {
      System.out.println("Credentials are invalid " + e.getClass() + ")");
  } finally {
    connection.close();
}This works, but it's a little silly. Basically, after Oracle "poisons" the connection with the bad openProxySession call, we execute any SQL statement we want. The statement is ignored, but executing it results in the "closed connection" error above. After this call, WebLogic recognizes the connection as bad, and purges it from the pool.
A simpler solution would be to "unpoison" the connection - to restore the connection to the state it was in before the openProxySession() call was executed. Is there any way to do that?
Edited by: Aaron Pieper on May 12, 2010 11:52 AM (java formatting)