Develop Reference

How to resolve this error:com.jcraft.jsch.JSchException: java.net.ConnectException: Connection refused: connect?

When I am trying to copy Excel sheet from my local to another windows server. File should be generating automatically at my local for every 3 min, at the time I have to generate in window server. But I got this error below I have mentioned here,
I am using code only you can refer this link: https://vinaydvd.wordpress.com/2013/12/08/copying-files-from-a-remote-linux-server-to-local-windows-server-using-java/
com.jcraft.jsch.JSchException: java.net.ConnectException: Connection refused: connect
at com.jcraft.jsch.Util.createSocket(Util.java:349)
at com.jcraft.jsch.Session.connect(Session.java:215)
at com.jcraft.jsch.Session.connect(Session.java:183)
at com.hpe.cdsh.cadence.GenerateExcel.main(GenerateExcel.java:28)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at java.net.Socket.connect(Socket.java:538)
at java.net.Socket.<init>(Socket.java:434)
at java.net.Socket.<init>(Socket.java:211)
at com.jcraft.jsch.Util.createSocket(Util.java:343)
... 3 more

Cannot open .jar file on MAC

I have used this crawler many many many times. At least once a day for the last few years. All of the sudden today when I try to open the .jar file I get this: 'The Java JAR file “Crawler.jar” Check the Console for possible error messages.' I have the latest version of java environment and SDK. I tried running 'java -jar Crawler.jar' and this was the result:
log4j:ERROR Could not read configuration file [data/log4j.properties].
java.io.FileNotFoundException: data/log4j.properties (No such file or directory)
at java.io.FileInputStream.open0(Native Method)
at java.io.FileInputStream.open(FileInputStream.java:195)
at java.io.FileInputStream.<init>(FileInputStream.java:138)
at java.io.FileInputStream.<init>(FileInputStream.java:93)
at org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:306)
at org.apache.log4j.PropertyConfigurator.configure(PropertyConfigurator.java:324)
at Crawler.main(Crawler.java:75)
log4j:ERROR Ignoring configuration file [data/log4j.properties].
Failed to open connection.
com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.net.ConnectException
MESSAGE: Connection refused
STACKTRACE:
java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at java.net.Socket.connect(Socket.java:538)
at java.net.Socket.<init>(Socket.java:434)
at java.net.Socket.<init>(Socket.java:244)
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(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:208)
at DatabaseConnector.getConnection(DatabaseConnector.java:34)
at DatabaseConnector.foundTable(DatabaseConnector.java:65)
at TextOutput.<init>(TextOutput.java:21)
at Crawler.main(Crawler.java:77)
** 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(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:208)
at DatabaseConnector.getConnection(DatabaseConnector.java:34)
at DatabaseConnector.foundTable(DatabaseConnector.java:65)
at TextOutput.<init>(TextOutput.java:21)
at Crawler.main(Crawler.java:77)
Exception in thread "main" java.lang.NullPointerException
at DatabaseConnector.foundTable(DatabaseConnector.java:68)
at TextOutput.<init>(TextOutput.java:21)
at Crawler.main(Crawler.java:77)
I am not a Java guy at all. If anyone has any insight on what I can do to fix this it would be greatly appreciate.

javax.mail.MessagingException: Connect failed;

Getting below exception while connecting to outlook.office365.com mail service. Using java, same piece of code works on windows machine.
Cipher: Crypto Permission check failed
Cipher: granted: (CryptoPermission * 128)
Cipher: requesting: (CryptoPermission AES 256)
javax.mail.MessagingException: Connect failed;
nested exception is:
java.net.ConnectException: Connection refused
at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:176)
at javax.mail.Service.connect(Service.java:291)
at javax.mail.Service.connect(Service.java:172)
at org.tester.task.TestMail.main(TestMail.java:25)
Caused by: java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:579)
at sun.security.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:618)
at sun.security.ssl.BaseSSLSocketImpl.connect(BaseSSLSocketImpl.java:160)
at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:284)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:227)
at com.sun.mail.pop3.Protocol.<init>(Protocol.java:98)
at com.sun.mail.pop3.POP3Store.getPort(POP3Store.java:227)
at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:172)
... 3 more

Apache Solr: I have run this command in Cygwin Terminal. ./nutch crawl urls -dir newCrawl -solr http://localhost:8939/solr/ -depth 10 -topN 10

SolrIndexer: starting at 2015-10-15 10:13:00
Adding 90 documents:
java.io.IOException: Job failed!
SolrDeleteDuplicates: starting at 2015-10-15 10:13:11
SolrDeleteDuplicates: Solr url: http://localhost:8939/solr/
Exception in thread "main" java.io.IOException: org.apache.solr.client.solrj.SolrServerException: java.net.ConnectException: Connection refused: connect
at org.apache.nutch.indexer.solr.SolrDeleteDuplicates$SolrInputFormat.getSplits(SolrDeleteDuplicates.java:200)
at org.apache.hadoop.mapred.JobClient.writeOldSplits(JobClient.java:810)
at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:781)
at org.apache.hadoop.mapred.JobClient.submitJob(JobClient.java:730)
at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:1249)
at org.apache.nutch.indexer.solr.SolrDeleteDuplicates.dedup(SolrDeleteDuplicates.java:373)
at org.apache.nutch.indexer.solr.SolrDeleteDuplicates.dedup(SolrDeleteDuplicates.java:353)
at org.apache.nutch.crawl.Crawl.run(Crawl.java:153)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
at org.apache.nutch.crawl.Crawl.main(Crawl.java:55)
Caused by: org.apache.solr.client.solrj.SolrServerException: java.net.ConnectException: Connection refused: connect
at org.apache.solr.client.solrj.impl.CommonsHttpSolrServer.request(CommonsHttpSolrServer.java:478)
at org.apache.solr.client.solrj.impl.CommonsHttpSolrServer.request(CommonsHttpSolrServer.java:244)
at org.apache.solr.client.solrj.request.QueryRequest.process(QueryRequest.java:89)
at org.apache.solr.client.solrj.SolrServer.query(SolrServer.java:118)
at org.apache.nutch.indexer.solr.SolrDeleteDuplicates$SolrInputFormat.getSplits(SolrDeleteDuplicates.java:198)
... 9 more
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:345)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at java.net.Socket.connect(Socket.java:538)
at java.net.Socket.<init>(Socket.java:434)
at java.net.Socket.<init>(Socket.java:286)
at org.apache.commons.httpclient.protocol.DefaultProtocolSocketFactory.createSocket(DefaultProtocolSocketFactory.java:80)
at org.apache.commons.httpclient.protocol.DefaultProtocolSocketFactory.createSocket(DefaultProtocolSocketFactory.java:122)
at org.apache.commons.httpclient.HttpConnection.open(HttpConnection.java:707)
at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:387)
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)
at org.apache.solr.client.solrj.impl.CommonsHttpSolrServer.request(CommonsHttpSolrServer.java:422)
... 13 more
How to resolve this issue?

Your solr url is not valid. You need to write the core as well. By default the core is collection1. Therefore, in your case the url is http://localhost:8983/solr/collection1

Solr doesn't seem to be running - Connection refused indicates that something is unable to contact whatever it should contact. Your configuration is probably broken, or you haven't started Solr or you're running on a different port.

Failed to connect to JMX while started to use the JMX authentication on Linux

My JMX client failed to connect to JMX server while I have started to use the JMX authentication.
I use Java 8 and Centos6.
I have configured the following settings:
JAVA_OPTS="${JAVA_OPTS} -Dcom.sun.management.jmxremote.authenticate=true -Dcom.sun.management.jmxremote.password.file=<path to password file> -Dcom.sun.management.jmxremote.access.file=<path to access file>"
Unfortunately my JMX client failed to connect to JMX server with the following exception:
java.io.IOException: Failed to retrieve RMIServer stub: javax.naming.ServiceUnavailableException [Root exception is java.rmi.ConnectException: Connection refused to host: localhost; nested exception is:
java.net.ConnectException: Connection refused]
at javax.management.remote.rmi.RMIConnector.connect(RMIConnector.java:369)
at javax.management.remote.JMXConnectorFactory.connect(JMXConnectorFactory.java:270)
at org.apache.catalina.ant.jmx.JMXAccessorTask.createJMXConnection(JMXAccessorTask.java:384)
at org.apache.catalina.ant.jmx.JMXAccessorTask.accessJMXConnection(JMXAccessorTask.java:439)
at org.apache.catalina.ant.jmx.JMXAccessorTask.getJMXConnection(JMXAccessorTask.java:477)
at org.apache.catalina.ant.jmx.JMXAccessorTask.execute(JMXAccessorTask.java:345)
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:292)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
at org.apache.tools.ant.Task.perform(Task.java:348)
at org.apache.tools.ant.Target.execute(Target.java:435)
at org.apache.tools.ant.Target.performTasks(Target.java:456)
at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1393)
at org.apache.tools.ant.Project.executeTarget(Project.java:1364)
at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
at org.apache.tools.ant.Project.executeTargets(Project.java:1248)
at org.apache.tools.ant.Main.runBuild(Main.java:851)
at org.apache.tools.ant.Main.startAnt(Main.java:235)
at org.apache.tools.ant.launch.Launcher.run(Launcher.java:280)
at org.apache.tools.ant.launch.Launcher.main(Launcher.java:109)
Caused by: javax.naming.ServiceUnavailableException [Root exception is java.rmi.ConnectException: Connection refused to host: localhost; nested exception is:
java.net.ConnectException: Connection refused]
at com.sun.jndi.rmi.registry.RegistryContext.lookup(RegistryContext.java:122)
at com.sun.jndi.toolkit.url.GenericURLContext.lookup(GenericURLContext.java:205)
at javax.naming.InitialContext.lookup(InitialContext.java:417)
at javax.management.remote.rmi.RMIConnector.findRMIServerJNDI(RMIConnector.java:1957)
at javax.management.remote.rmi.RMIConnector.findRMIServer(RMIConnector.java:1924)
at javax.management.remote.rmi.RMIConnector.connect(RMIConnector.java:287)
... 22 more
Caused by: java.rmi.ConnectException: Connection refused to host: localhost; nested exception is:
java.net.ConnectException: Connection refused
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:619)
at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:216)
at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:202)
at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:342)
at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source)
at com.sun.jndi.rmi.registry.RegistryContext.lookup(RegistryContext.java:118)
... 27 more
Caused by: java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:345)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at java.net.Socket.connect(Socket.java:538)
at java.net.Socket.<init>(Socket.java:434)
at java.net.Socket.<init>(Socket.java:211)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:40)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:148)
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:613)
... 32 more

To solve it I read carefully the documentation:
http://docs.oracle.com/javase/7/docs/technotes/guides/management/agent.html#gdeup
The following comment about the password file is very important:
You must ensure that only the owner has read and write permissions on this file, since it contains the passwords in clear text. For security reasons, the system checks that the file is only readable by the owner and exits with an error if it is not.
I set read permission to a user and my client successfully connects to the JMX server:
chmod 400 <path to password file>