org.apache.commons.dbcp.SQLNestedException: Cannot get a connection, pool exhausted, cause:  
java.util.NoSuchElementException: Timeout waiting for idle object

/*
 * Created on 3 nov. 2003
 *
 * To change the template for this generated file go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */
package data;
import java.sql.*;
import javax.sql.*;
import javax.naming.*;
 
/**
 *  
 *
 * To change the template for this generated type comment go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */
public class myBdConnect {
 public myBdConnect() {
 
 }
 
 public Connection connect() {
  Connection conn= null;
  try {
   Context ctx = new InitialContext();
   if (ctx == null)
    throw new Exception("Boom - No Context" );
   DataSource ds =
    (DataSource) ctx.lookup("java:comp/env/jdbc/VM" );
   if (ds != null) {
    conn = ds.getConnection();
    if (conn != null) {
     return conn;
    }
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
  return conn;
 }
 
}

public int insertBd() {
  PreparedStatement pInsert;
  PreparedStatement pMax;
  String insert = "insert into theme (id, tradid) values (?,?)";
  String max = "select max(id) from theme";
  int leMax = 0;
  try {
   myBdConnect m = new myBdConnect();
   Connection conn = m.connect();
   pMax = conn.prepareStatement(max);
   pMax.clearParameters();
   ResultSet rst1 = pMax.executeQuery();
   if (rst1.next()) {
    leMax = rst1.getInt(1);
    this.id = leMax;
   }
   pInsert = conn.prepareStatement(insert);
   pInsert.clearParameters();
   pInsert.setInt(1, this.id);
   pInsert.setInt(2, this.tradid);
   pInsert.executeUpdate();
   conn.close();
  } catch (Exception e) {
   e.printStackTrace();
  }
  return leMax;
 }

org.apache.commons.dbcp.SQLNestedException: Cannot get a connection, pool exhausted, cause:  
java.util.NoSuchElementException: Timeout waiting for idle object

<parameter>
             <name>removeAbandoned</name>
              <value>true</value>
</parameter>

Random Connection Closed Exceptions  
These can occur when one request gets a db connection from the connection pool and closes it twice. When using a connection pool, closing the connection just returns it to the pool for reuse by another request, it doesn't close the connection. And Tomcat uses multiple threads to handle concurrent requests. Here is an example of the sequence of events which could cause this error in Tomcat:  
 
  Request 1 running in Thread 1 gets a db connection.
 
  Request 1 closes the db connection.
 
  The JVM switches the running thread to Thread 2
 
  Request 2 running in Thread 2 gets a db connection
  (the same db connection just closed by Request 1).
 
  The JVM switches the running thread back to Thread 1
 
  Request 1 closes the db connection a second time in a finally block.
 
  The JVM switches the running thread back to Thread 2
 
  Request 2 Thread 2 tries to use the db connection but fails
  because Request 1 closed it.
 
Here is an example of properly written code to use a db connection obtained from a connection pool:  
  Connection conn = null;
  Statement stmt = null;  // Or PreparedStatement if needed
  ResultSet rs = null;
  try {
    conn = ... get connection from connection pool ...
    stmt = conn.createStatement("select ..." );
    rs = stmt.executeQuery();
    ... iterate through the result set ...
    rs.close();
    rs = null;
    stmt.close();
    stmt = null;
    conn.close(); // Return to connection pool
    conn = null;  // Make sure we don't close it twice
  } catch (SQLException e) {
    ... deal with errors ...
  } finally {
    // Always make sure result sets and statements are closed,
    // and the connection is returned to the pool
    if (rs != null) {
      try { rs.close(); } catch (SQLException e) { ; }
      rs = null;
    }
    if (stmt != null) {
      try { stmt.close(); } catch (SQLException e) { ; }
      stmt = null;
    }
    if (conn != null) {
      try { conn.close(); } catch (SQLException e) { ; }
      conn = null;
    }
  }

    <Context className="org.apache.catalina.core.StandardContext" cachingAllowed="true" charsetMapperClass="org.apache.catalina.util.CharsetMapper" cookies="true" crossContext="false" debug="0" docBase="/usr/local/tomcat/webapps/elearning" mapperClass="org.apache.catalina.core.StandardContextMapper" path="/elearning" privileged="false" reloadable="true" swallowOutput="false" useNaming="true" wrapperClass="org.apache.catalina.core.StandardWrapper">  
        <Resource name="jdbc/VM" auth="Container" type="javax.sql.DataSource"/>  
        <ResourceParams name="jdbc/VM">  
          <parameter>  
               <name>factory</name>  
               <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>  
          </parameter>  
          <parameter>  
               <name>driverClassName</name>  
               <value>org.postgresql.Driver</value>  
          </parameter>  
          <parameter>  
               <name>url</name>  
               <value>jdbc:postgresql://localhost:5432/elearningbase?charset=LATIN1</value>  
          </parameter>  
          <parameter>  
               <name>username</name>  
               <value>xxxx</value>  
          </parameter>  
          <parameter>  
               <name>password</name>  
               <value>xxxx</value>  
          </parameter>  
          <parameter>  
               <name>maxActive</name>  
               <value>0</value>  
         </parameter>  
          <parameter>  
               <name>maxIdle</name>  
               <value>0</value>  
         </parameter>  
          <parameter>  
               <name>maxWait</name>  
               <value>0</value>  
          </parameter>  
        </ResourceParams>  
     </Context>

   <!-- Maximum number of dB connections in pool. Make sure you
         configure your mysqld max_connections large enough to handle
         all of your db connections. Set to 0 for no limit.
         -->
    <parameter>
      <name>maxActive</name>
      <value>100</value>
    </parameter>