We Keep Coding

vert.x getting - failed to create a child event loop

I am creating about 150 files of around 5MB sizes. Vertx file APIs gives an exception randomly after creating 10-15 files "failed to create a child event loop".
(I am using vertx3 and java8)
Below is my code snippet (After I get a callback then only I call the function again to create the next file. So, file creation is never concurrent):
Vertx.vertx().fileSystem().writeFile(filepath,
Buffer.buffer(dataList.toString()), result -> {
if (result.succeeded()) {
System.out.println("File written");
} else {
System.err.println("Oh oh ..." + result.cause());
}
lambda.callback();
});
Below is my exception stack trace:
java.lang.IllegalStateException: failed to create a child event loop
at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:68)
at io.netty.channel.MultithreadEventLoopGroup.<init>(MultithreadEventLoopGroup.java:49)
at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:61)
at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:52)
at io.vertx.core.impl.VertxImpl.<init>(VertxImpl.java:132)
at io.vertx.core.impl.VertxImpl.<init>(VertxImpl.java:126)
at io.vertx.core.impl.VertxImpl.<init>(VertxImpl.java:122)
at io.vertx.core.impl.VertxFactoryImpl.vertx(VertxFactoryImpl.java:34)
at io.vertx.core.Vertx.vertx(Vertx.java:78)
at rc_datawarehouse.CsvToJsonChunkWriter.writeCsvChunkToFiles(CsvToJsonChunkWriter.java:73)
at rc_datawarehouse.CsvToJsonReadWrite.lambda$2(CsvToJsonReadWrite.java:119)
at rc_datawarehouse.CsvToJsonReadWrite$$Lambda$16/1470881859.handle(Unknown Source)
at io.vertx.core.file.impl.AsyncFileImpl.handleData(AsyncFileImpl.java:335)
at io.vertx.core.file.impl.AsyncFileImpl.lambda$doRead$285(AsyncFileImpl.java:320)
at io.vertx.core.file.impl.AsyncFileImpl$$Lambda$17/1067800899.handle(Unknown Source)
at io.vertx.core.file.impl.AsyncFileImpl$2.lambda$done$289(AsyncFileImpl.java:408)
at io.vertx.core.file.impl.AsyncFileImpl$2$$Lambda$18/1632681662.handle(Unknown Source)
at io.vertx.core.impl.ContextImpl.lambda$wrapTask$15(ContextImpl.java:314)
at io.vertx.core.impl.ContextImpl$$Lambda$5/1780132728.run(Unknown Source)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:357)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:357)
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:111)
at java.lang.Thread.run(Unknown Source)
Caused by: io.netty.channel.ChannelException: failed to open a new selector
at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:128)
at io.netty.channel.nio.NioEventLoop.<init>(NioEventLoop.java:120)
at io.netty.channel.nio.NioEventLoopGroup.newChild(NioEventLoopGroup.java:87)
at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:64)
... 22 more
Caused by: java.io.IOException: Unable to establish loopback connection
at sun.nio.ch.PipeImpl$Initializer.run(Unknown Source)
at sun.nio.ch.PipeImpl$Initializer.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at sun.nio.ch.PipeImpl.<init>(Unknown Source)
at sun.nio.ch.SelectorProviderImpl.openPipe(Unknown Source)
at java.nio.channels.Pipe.open(Unknown Source)
at sun.nio.ch.WindowsSelectorImpl.<init>(Unknown Source)
at sun.nio.ch.WindowsSelectorProvider.openSelector(Unknown Source)
at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:126)
... 25 more
Caused by: java.net.SocketException: No buffer space available (maximum connections reached?): connect
at sun.nio.ch.Net.connect0(Native Method)
at sun.nio.ch.Net.connect(Unknown Source)
at sun.nio.ch.Net.connect(Unknown Source)
at sun.nio.ch.SocketChannelImpl.connect(Unknown Source)
at java.nio.channels.SocketChannel.open(Unknown Source)
at sun.nio.ch.PipeImpl$Initializer$LoopbackConnector.run(Unknown Source)
... 34 more

I got my answer from the forum here (Thanks Jez)
Vertx.vertx() is the culprit. It creates a new vertx every time leading to multiple eventloops which seems to be the problem.
I cached it in a variable, rather than using Vertx.vertx() every time and it worked
cachedVertx.fileSystem().writeFile(...)

httpclient throws readtimeout exception after setting SO_TIMEOUT to infinity

I am using httpclient for Client Side to connect Server. I did not set any timeout(readtimeout - SO_TIMEOUT). From the docs i found that if the timeout not specified then it interpreted as infinity(0).
But httpclient throws "java.net.SocketTimeoutException: Read timed out" exception within 20 to 30 seconds after connecting to server on client side. Also note: i am not facing this issue consistently.
What to do to resolve this? Help me.
Stack Trace :
java.net.SocketTimeoutException: Read timed out
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(Unknown Source)
at com.sun.net.ssl.internal.ssl.InputRecord.readFully(Unknown Source)
at com.sun.net.ssl.internal.ssl.InputRecord.read(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.writeRecord(Unknown Source)
at com.sun.net.ssl.internal.ssl.AppOutputStream.write(Unknown Source)
at java.io.BufferedOutputStream.flushBuffer(Unknown Source)
at java.io.BufferedOutputStream.write(Unknown Source)
at java.io.FilterOutputStream.write(Unknown Source)
at org.apache.commons.httpclient.methods.multipart.Part.sendDispositionHeader(Part.java:220)
at org.apache.commons.httpclient.methods.multipart.Part.send(Part.java:308)
at org.apache.commons.httpclient.methods.multipart.Part.sendParts(Part.java:385)
at org.apache.commons.httpclient.methods.multipart.MultipartRequestEntity.writeRequest(MultipartRequestEntity.java:164)
at org.apache.commons.httpclient.methods.EntityEnclosingMethod.writeRequestBody(EntityEnclosingMethod.java:499)
at org.apache.commons.httpclient.HttpMethodBase.writeRequest(HttpMethodBase.java:2114)
at org.apache.commons.httpclient.HttpMethodBase.execute(HttpMethodBase.java:1096)
at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:398)
at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:171)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:323)
Code:
HttpClient client = new HttpClient();
HttpConnectionManager conn = new SimpleHttpConnectionManager(true);
conn.getParams().setConnectionTimeout(25000);
client.setHttpConnectionManager(conn);
PostMethod meth = new PostMethod(url);//url is server url
meth.getParams().setCookiePolicy(CookiePolicy.IGNORE_COOKIES);
Part p[] = new Part[parts.size()];//parts is an arraylist variable for server process params
p = (Part[])parts.toArray(p);
((PostMethod)meth).setRequestEntity(new MultipartRequestEntity(p,meth.getParams()));
meth.setRequestHeader("Content-Type", "application/x-www-form-urlencoded; charset=utf-8");
HttpMethod method = (HttpMethod)meth;
int status = client.executeMethod(method);
Exception thrown on client executeMethod
Thanks,
Ganesan

I found a net connection error while using localhost in jdbc

I wrote this program to connect with my database which is on the same computer but i found a net connection error each time. com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
import java.sql.*;
public class Demo {
public static void main(String[] args) {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection connection = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/db","username","pwd");
Statement stmt = connection.createStatement();
String str="SHOW TABLES";
ResultSet resultSet=stmt.executeQuery(str);
while (resultSet.next()) {
System.out.println(resultSet.getString(1));
}
}catch(Exception e){
e.printStackTrace();
}
}
}
My Stacktrace is:-
com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.net.ConnectException
MESSAGE: Connection refused: connect
STACKTRACE:
java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(Unknown Source)
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:271)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771)
at com.mysql.jdbc.Connection.<init>(Connection.java:1555)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at Demo.main(Demo.java:8)
** END NESTED EXCEPTION **
Last packet sent to the server was 0 ms ago.
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2847)
at com.mysql.jdbc.Connection.<init>(Connection.java:1555)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at Demo.main(Demo.java:8)

Try this:
DriverManager.getConnection("jdbc:mysql://localhost:3306/dbname","username","password");
If this is not sorted out go to where you installed Mysql and open MySQL Notifier and check server is running or not if not start it and then try executing your program.

This error was mainly due to Mysql server not reachable or not running. Check with below points:
1. Check your DB Connection whether MYSQL is up and running.
2. Check if you are able to connect from command prompt
3. Restart the mysql server and try again.

Connect active directory with the support of ssl (ldaps)

am trying to connect with active directory with the support of ssl.
i tried the steps from following web site.
http://confluence.atlassian.com/display/CROWD/Configuring+an+SSL+Certificate+for+Microsoft+Active+Directory
when i try to connect active directory from the java code it gives following error.
Exception in thread "main" javax.naming.CommunicationException: simple bind fail
ed: 172.16.12.4:636 [Root exception is java.net.SocketException: Connection rese
t]
at com.sun.jndi.ldap.LdapClient.authenticate(Unknown Source)
at com.sun.jndi.ldap.LdapCtx.connect(Unknown Source)
at com.sun.jndi.ldap.LdapCtx.<init>(Unknown Source)
at com.sun.jndi.ldap.LdapCtxFactory.getUsingURL(Unknown Source)
at com.sun.jndi.ldap.LdapCtxFactory.getUsingURLs(Unknown Source)
at com.sun.jndi.ldap.LdapCtxFactory.getLdapCtxInstance(Unknown Source)
at com.sun.jndi.ldap.LdapCtxFactory.getInitialContext(Unknown Source)
at javax.naming.spi.NamingManager.getInitialContext(Unknown Source)
at javax.naming.InitialContext.getDefaultInitCtx(Unknown Source)
at javax.naming.InitialContext.init(Unknown Source)
at javax.naming.InitialContext.<init>(Unknown Source)
at javax.naming.directory.InitialDirContext.<init>(Unknown Source)
at ConnectActiveDirectory.main(ConnectActiveDirectory.java:39)
Caused by: java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at com.sun.net.ssl.internal.ssl.InputRecord.readFully(Unknown Source)
at com.sun.net.ssl.internal.ssl.InputRecord.read(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.waitForClose(Unknown Sourc
e)
at com.sun.net.ssl.internal.ssl.HandshakeOutStream.flush(Unknown Source)
at com.sun.net.ssl.internal.ssl.Handshaker.kickstart(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.kickstartHandshake(Unknown
Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(Un
known Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.writeRecord(Unknown Source
)
at com.sun.net.ssl.internal.ssl.AppOutputStream.write(Unknown Source)
at java.io.BufferedOutputStream.flushBuffer(Unknown Source)
at java.io.BufferedOutputStream.flush(Unknown Source)
at com.sun.jndi.ldap.Connection.writeRequest(Unknown Source)
at com.sun.jndi.ldap.Connection.writeRequest(Unknown Source)
at com.sun.jndi.ldap.LdapClient.ldapBind(Unknown Source)
... 13 more
Code that am using is
import java.util.Hashtable;
import javax.naming.*;
import javax.naming.directory.*;
public class ConnectActiveDirectory {
public static void main(String[] args) throws NamingException {
Hashtable env = new Hashtable();
env.put(Context.SECURITY_AUTHENTICATION, "simple");
env.put(Context.SECURITY_PRINCIPAL,"Administrator#mysite.com");
env.put(Context.SECURITY_CREDENTIALS, "password");
env.put(Context.INITIAL_CONTEXT_FACTORY,"com.sun.jndi.ldap.LdapCtxFactory");
env.put(Context.PROVIDER_URL, "ldaps://172.16.12.4:636/cn=Users,dc=mysite,dc=com");
try{
java.io.InputStream in = new java.io.FileInputStream("C:\\client.crt");
java.security.cert.Certificate c = java.security.cert.CertificateFactory.getInstance("X.509").generateCertificate(in);
java.security.KeyStore ks = java.security.KeyStore.getInstance("JKS");
ks.load(null);
if (!ks.containsAlias("alias ldap")) {
ks.setCertificateEntry("alias ldap", c);
}
java.io.OutputStream out = new java.io.FileOutputStream("C:\\keystorefile.jks");
char[] kspass = "changeit".toCharArray();
ks.store(out, kspass);
out.close();
}catch(Exception e){
e.printStackTrace();
}
System.setProperty("javax.net.ssl.trustStore", "C:\\keystorefile.jks");
DirContext ctx = new InitialDirContext(env);
NamingEnumeration enm = ctx.list("");
while (enm.hasMore()) {
System.out.println(enm.next());
}
ctx.close();
}
}
does am doing any mistake?
where can i get good tutorial to do ssl connection with active directory ?
does http://confluence.atlassian.com/display/CROWD/Configuring+an+SSL+Certificate+for+Microsoft+Active+Directory site has correct steps to create and connect active directory with ssl?
could any on please help me.

I had a similar issue after my AD domain was renamed. After reinstalling certificate services, you need to delete and re-issue the certificate issued to your Domain Controller. Steps:
Open MMC
Add Snap In > Certificates > Computer > Local Computer
Navigate to Personal > Certificates
Delete any old certificates issued to this machine (in my case, these were issued by the old CA)
Right click on Certificates folder, click Request New Certificate.
Follow the steps to issue the new certificate to your domain controller.
Restart (not sure if this is necessary, but I restarted before it worked)

I had the same error message using Atlassian Crowd and Active Directory over SSL. It is not applicable to this specific question, but when I tried to find out what was happening this thread was the first Google search hit, so I will write it down here.
In my case I first tested without SSL and then changed to SSL. Turns out I forgot to change the protocol used in the Crowd Connector settings.
Before: ldap://:389
After: ldaps://:636
Accidentally using ldap://:636 gave me the "Connection reset" error.

Problem with SAX

I'm having the code below..
System.setProperty("http.proxyHost","176.6.129.25") ;
System.setProperty("http.proxyPort", "8080") ;
Authenticator.setDefault(new MyAuthenticator());
//http://deadlock.netbeans.org/hudson/api/xml
*URL url = new URL("http://in8301782d:8080/api/xml");*
Document dom = new SAXReader().read(url);
for( Element job : (List<Element>)dom.getRootElement().elements("job")) {
System.out.println(String.format("Name:%s\tStatus:%s",
job.elementText("name"), job.elementText("color")));
}
This code is working if I replace with http://deadlock.netbeans.org/hudson/api/xml , but it is not working with http://in8301782d:8080/api/xml. Infact If I type the samething in browser it is working.. If I replace the hostname with Ip address also not working.
The exception I'm getting is below.
*With in8301782d (machine name)* :
xception in thread "main" org.dom4j.DocumentException: http://in8301782d:8080/api/xml Nested exception: http://in8301782d:8080/api/xml
at org.dom4j.io.SAXReader.read(SAXReader.java:484)
at org.dom4j.io.SAXReader.read(SAXReader.java:291)
at com.sg.hudson.ci.Main.main(Main.java:140)
Nested exception:
java.io.FileNotFoundException: http://in8301782d:8080/api/xml
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1243)
at org.apache.xerces.impl.XMLEntityManager.setupCurrentEntity(Unknown Source)
at org.apache.xerces.impl.XMLVersionDetector.determineDocVersion(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
at org.dom4j.io.SAXReader.read(SAXReader.java:465)
at org.dom4j.io.SAXReader.read(SAXReader.java:291)
at com.sg.hudson.ci.Main.main(Main.java:140)
*With Ip (http://176.6.55.55:8080/api/xml):*
Exception in thread "main" org.dom4j.DocumentException: Server returned HTTP response code: 503 for URL: http://176.6.66.156:8080/api/xml Nested exception: Server returned HTTP response code: 503 for URL: http://176.6.66.156:8080/api/xml
at org.dom4j.io.SAXReader.read(SAXReader.java:484)
at org.dom4j.io.SAXReader.read(SAXReader.java:291)
at com.sg.hudson.ci.Main.main(Main.java:140)
Nested exception:
java.io.IOException: Server returned HTTP response code: 503 for URL: http://176.6.66.156:8080/api/xml
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1245)
at org.apache.xerces.impl.XMLEntityManager.setupCurrentEntity(Unknown Source)
at org.apache.xerces.impl.XMLVersionDetector.determineDocVersion(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
at org.dom4j.io.SAXReader.read(SAXReader.java:465)
at org.dom4j.io.SAXReader.read(SAXReader.java:291)
at com.sg.hudson.ci.Main.main(Main.java:140)

This doesn't appear to be a problem with your code.
In the first exception, SAX is telling you that it cannot find http://in8301782d:8080/api/xml - it cannot reach this URL. If the URL works in your browser, then perhaps the proxy setup is at fault.
In the second exception, SAX is reporting that the server is returning a non-success HTTP status code of 503, which (according to the HTTP specification) means:
The server is currently unable to handle the request due to a temporary overloading or maintenance of the server. The implication is that this is a temporary condition which will be alleviated after some delay.
Of course, the application sitting at this URL may be sending you a HTTP 503 for some non-standard reason as well.