I am facing a problem in closing database conenctions. I am getting the below error
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267137 [http-8080-Processor23] FATAL com.abc.r2.dwrclasses.DBUtilities - Failed to get a connection from DataSource JNDI/TPXSRUDB
org.apache.commons.dbcp.SQLNestedException: Cannot get a connection, pool exhausted
at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:103)
at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:540)
at com.abc.r2.dwrclasses.DBUtilities.getNativeConnection(DBUtilities.java:110)
at com.abc.r2.dwrclasses.ProcedureCaller.callProcedure(ProcedureCaller.java:81)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.directwebremoting.impl.DefaultRemoter$1.doFilter(DefaultRemoter.java:740)
at org.directwebremoting.impl.DefaultRemoter.execute(DefaultRemoter.java:744)
at org.directwebremoting.impl.DefaultRemoter.execute(DefaultRemoter.java:593)
at org.directwebremoting.dwrp.BaseCallHandler.handle(BaseCallHandler.java:90)
at org.directwebremoting.servlet.UrlProcessor.handle(UrlProcessor.java:120)
at org.directwebremoting.servlet.DwrServlet.doPost(DwrServlet.java:141)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.oracle.determinations.web.platform.util.CharsetFilter.doFilter(CharsetFilter.java:46)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.util.NoSuchElementException: Timeout waiting for idle object
at org.apache.commons.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:756)
at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:95)
... 42 more
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I have written a DBUtilities.java file which gets the connection using JNDI and returns the connection object. This connection object is then used in other java classes for quering database (calling procedures) and then closed when done. However, after some amount of successful connection, its giving the above error. The code written in my class is given below. Can anyone please let me know whats wrong in the code or is there a problem with the database. I am using oracle 10g.
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package com.abc.r2.dwrclasses;
/*
* Utilites.java
*
* Created on 08 July 2004, 11:55
*/
import java.sql.*;
import javax.sql.*;
import javax.naming.*;
import java.util.*;
import org.apache.log4j.Logger;
import org.apache.log4j.NDC;
import org.apache.commons.dbutils.DbUtils;
import com.ibm.ws.rsadapter.jdbc.WSJdbcConnection;
import com.ibm.ws.rsadapter.jdbc.WSJdbcUtil;
/**
* Abstract class containing useful database methods.
* @author Rajan Panchal
*/
public abstract class DBUtilities {
private static final Logger log = Logger.getLogger(DBUtilities.class);
private static Context initCtx; // Initial context
private static Context envCtx; // Environment context
static ResourceBundle rb;
static String appServer;
DataSource ds;
// Only get the JNDI context once, it's expensive.
/* Get the JNDI context depending upon the configuration stored in appconfiguration.properties file in configuration folder */
static {
try {
rb = ResourceBundle.getBundle("configuration.queries");
appServer = rb.getString("APP_SERVER");
log.debug("Application Server: "+appServer);
if(appServer.equalsIgnoreCase("TOMCAT")){
initCtx = new InitialContext();
envCtx = (Context)initCtx.lookup("java:/comp/env");
}else if(appServer.equalsIgnoreCase("WEBSPHERE")){
Hashtable env = new Hashtable();
env.put("java.naming.factory.initial","com.ibm.websphere.naming.WsnInitialContextFactory");
System.out.println("INITIAL_CONTEXT_FACTORY: com.ibm.websphere.naming.WsnInitialContextFactory");
initCtx = new InitialContext(env);
}
} catch (javax.naming.NamingException e) {
log.fatal("Failed to get JNDI context on "+appServer, e);
throw new RuntimeException(e);
}
}
/**
* Get a JDBC connection
* @param jndiName the JNDI name of the datasource
* @return a Connection to the datasource
*/
public static Connection getConnection(String jndiName) {
int maxtry = 10;
int DBConnectTry = 0;
while( DBConnectTry++ < maxtry){
log.info("trying to connect:"+DBConnectTry);
try {
if(appServer.equalsIgnoreCase("TOMCAT")){
DataSource ds = (DataSource)envCtx.lookup(jndiName);
log.debug("Returning connection object for "+appServer);
return ds.getConnection();
}else if(appServer.equalsIgnoreCase("WEBSPHERE")){
DataSource ds = (DataSource)initCtx.lookup(jndiName);
log.debug("Returning connection object for "+appServer);
return ds.getConnection();
}
} catch (javax.naming.NamingException e) {
log.fatal("JNDI lookup failed for DataSource "+jndiName, e);
throw new RuntimeException(e);
} catch (SQLException e) {
log.fatal("Failed to get a connection from DataSource "+jndiName, e);
log.info("Wait for 1 sec...");
Long WaitTime = System.currentTimeMillis()+1000L;
while(System.currentTimeMillis()<WaitTime){
}
log.info("Wait Over retrying...");
}
}
return null;
}
/* This method returns the native connection for executing the pl/sql procedure with array descriptors.*/
public static Connection getNativeConnection(String jndiName) {
int maxtry = 10;
int DBConnectTry = 0;
Connection conn;
while( DBConnectTry++ < maxtry){
log.info("trying to connect:"+DBConnectTry);
try {
if(appServer.equalsIgnoreCase("TOMCAT")){
DataSource ds = (DataSource)envCtx.lookup(jndiName);
conn = ds.getConnection();
if (conn instanceof org.apache.commons.dbcp.DelegatingConnection) {
log.debug("detected apache commons dbcp datasource");
conn = ((org.apache.commons.dbcp.DelegatingConnection) conn).getInnermostDelegate();
}
return conn;
}else if(appServer.equalsIgnoreCase("WEBSPHERE")){
DataSource ds = (DataSource)initCtx.lookup(jndiName);
conn = (Connection) WSJdbcUtil.getNativeConnection((WSJdbcConnection)ds.getConnection());
return conn;
}
} catch (javax.naming.NamingException e) {
log.fatal("JNDI lookup failed for DataSource "+jndiName, e);
throw new RuntimeException(e);
} catch (SQLException e) {
log.fatal("Failed to get a connection from DataSource "+jndiName, e);
log.info("Wait for 1 sec...");
Long WaitTime = System.currentTimeMillis()+1000L;
while(System.currentTimeMillis()<WaitTime){
}
log.info("Wait Over retrying...");
}
}
return null;
}
/**
* Utility method to close a connection, and/or a statement, and/or a resultset
* @param con Connection, or null
* @param stmt Statement, or null
* @param rs ResultSet, or null
*/
public static void cleanUp(Connection con, Statement stmt, ResultSet rs) {
try {
if (rs != null) {
while (rs.next()) // Drain the resultset.
;
rs.close();
}
if (stmt != null)
stmt.close();
if (con != null)
con.close();
} catch (SQLException e) {
log.error("Failed to close connection", e);
}
}
/**
* Convert a ResultSet to a List of Maps
* This enables the results to be processed
* using the JSTL forEach tag.
* @param rs the ResultSet to convert
* @throws SQLException may be thrown by ResultSet operations
* @return the converted ResultSet
*/
@SuppressWarnings("unchecked")
public static List convertResultSet(ResultSet rs) throws SQLException {
try {
NDC.push("convertResultSet");
log.debug("start");
// Get column names
ResultSetMetaData rsmd = rs.getMetaData();
int numberOfColumns = rsmd.getColumnCount();
log.debug("Column Count is "+numberOfColumns);
String[] names = new String[numberOfColumns];
int[] types = new int[numberOfColumns];
for (int i = 0; i < names.length; ++i) {
names[i] = rsmd.getColumnName(i+1);
types[i] = rsmd.getColumnType(i+1);
log.debug(" Name="+names[i]);
}
List l = new LinkedList();
// Loop through the rows
while (rs.next()) {
log.debug("Processing row "+l.size());
Map m = new HashMap();
// Loop through the columns
for (int i = 0; i < names.length; ++i) {
Object o;
switch(types[i]) {
case Types.DATE:
o = rs.getTimestamp(i+1);
break;
default:
o = rs.getString(i+1);
}
log.debug(" "+names[i]+"='"+o+"'");
/*
if (o == null)
o = " ";
*/
m.put(names[i], o);
}
// Add the map to the list
l.add(m);
log.debug("done");
}
return l;
} finally {
NDC.pop();
}
}
@SuppressWarnings("unchecked")
public static void formatDates(List rows, java.text.SimpleDateFormat fmt) {
Iterator it1 = rows.iterator();
while (it1.hasNext()) {
Map m = (Map)it1.next();
List names = new LinkedList();
Iterator it2 = m.entrySet().iterator();
while (it2.hasNext()) {
Map.Entry e = (Map.Entry)it2.next();
if (e.getValue() instanceof Timestamp) {
names.add(e.getKey());
}
}
it2 = names.iterator();
while(it2.hasNext()) {
String name = (String)it2.next();
Timestamp t = (Timestamp) m.get(name);
String s = fmt.format(t);
m.put(name,s);
}
}
}
/**
* Generate dummy results as a List of Maps
*
* @param columns A string array containing the required columns names
* @param rows The number of rows to generate
* @return The data as a List of Maps
*/
@SuppressWarnings("unchecked")
public static List generateTestData(String[] columns, int rows) {
try {
NDC.push("generateTestData");
List l = new LinkedList();
for (int row = 1; row <= rows; ++row) {
Map m = new HashMap();
// Loop through the columns
for (int i = 0; i < columns.length; ++i) {
String s = columns[i]+" "+row;
m.put(columns[i], s);
}
// Add the map to the list
l.add(m);
}
return l;
} finally {
NDC.pop();
}
}
/**
* retrieves just the error code from an oracle message
*/
public static String parseOracleError(String errCode, String errMsg) {
int start = 0;
int end = 0;
start = errMsg.indexOf(errCode);
end = errMsg.indexOf(":", start);
return errMsg.substring(start, end);
}
/**Close a <code>Connection</code>, <code>Statement</code> and
* <code>ResultSet</code> cleanly.
*/
public static void close(Connection conn, Statement stmt, ResultSet rs) {
try {
DbUtils.close(rs);
DbUtils.close(stmt);
DbUtils.close(conn);
} catch (SQLException sqlEx) {
log.error("Failed to close database objects cleanly.", sqlEx);
}
}
/**Close a <code>Connection</code> and <code>Statement</code> cleanly.
*/
public static void close(Connection conn, Statement stmt) {
try {
DbUtils.close(stmt);
DbUtils.close(conn);
} catch (SQLException sqlEx) {
log.error("Failed to close database objects cleanly.", sqlEx);
}
}
/**Close a <code>Connection</code> and <code>Statement</code> quietly.
*/
public static void closeQuietly(Connection conn, Statement stmt) {
DbUtils.closeQuietly(stmt);
DbUtils.closeQuietly(conn);
}
/**Close a <code>Connection</code>, <code>Statement</code> and
* a <code>ResultSet</code> quietly.
*/
public static void closeQuietly(Connection conn, Statement stmt, ResultSet rst) {
DbUtils.closeQuietly(rst);
DbUtils.closeQuietly(stmt);
DbUtils.closeQuietly(conn);
}
}
Your cleanUp method could fail to close a given SQLConnection if it tries to also close a ResultSet and/or Statement beforehand. e.g. if closing the ResultSet fails and throws a SQLException, it would jump directly to the catch block, without even trying to close the connection. Are there errors on closing a connection in your log?
To avoid that problem, either provide dedicated cleanUp methods that only attempt to close a single thing or wrap each attempt to close sth. inside its own try/catch block. The same advice applies to the various close and closeQuietly methods.
// edit
This code section is most likely harmful. In getNativeConnection(String jndiName) :
The DelegatingConnection seems to be a proxy that handles the pooling of the connection. As you are unwrapping the “native” connection the DelegatingConnection-Proxy is not notified when the connection is closed and cannot return it to the pool. That way the pool fills up with closed connections until the limit is reached.