Running a java program via nailgun - java

Can someone please explain how do I start a program called main.java using Nailgun. It's been a complete nightmare for me and I cannot find any sort of tutorial on the web which explains it clearly.
Do I need to include anything extra in my program to run them?
I'm trying to follow the instructions given on the Nailgun website where it says:
Launch the Nailgun server with "java com.martiansoftware.nailgun.NGServer"
But the output I get is:
Error: Could not find or load main class com.martiansoftware.nailgun.NGServer
Also, when I try to run my compiled java program, the output is:
java.lang.ClassNotFoundException: main
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:274)
at com.martiansoftware.nailgun.NGSession.run(NGSession.java:261)

I think the idea with nailgun is that you have to include the classpath when you launch the server, like this:
$ java -cp /usr/share/java/nailgun-0.9.0.jar:path/to/myapp.jar -server com.martiansoftware.nailgun.NGServer 127.0.0.1 &
NGServer started on 127.0.0.1, port 2113.
[1] 22443
$ ng-nailgun com.user4215685.main

Related

Failing to start java program ClassNotFound exception received

Trying to start java program on linux but it fails to locate JSoup jar file. I have checked other questions and found on how to add libraries while compiling and while trying to run it but I am not sure if I am doing it correctly because it still fails to load the library....
I enter the following commands:
root#vps5441:/var/www/var/www/TimetableLoader# javac -cp /var/www/var/www/TimetableLoader/jsoup-1.8.1.jar:/var/www/var/www/TimetableLoader/mysql-connector-java-5.0.8/mysql-connector-java-5.0.8-bin.jar. TimetableLoader.java
root#vps5441:/var/www/var/www/TimetableLoader# java -cp /var/www/var/www/TimetableLoader/jsoup-1.8.1.jar:/var/www/var/www/TimetableLoader/mysql-connector-java-5.0.8/mysql-connector-java-5.0.8-bin.jar. -classpath /var/www/var/www/TimetableLoader/ TimetableLoader
And I get the following error when the program tries to access the JSoup library.
Exception in thread "main" java.lang.NoClassDefFoundError: org/jsoup/Jsoup
at TimetableLoader.main(TimetableLoader.java:46)
Caused by: java.lang.ClassNotFoundException: org.jsoup.Jsoup
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
... 1 more
I assume jsoup-1.8.1.jar is in the current directory?
You don't generally need both -classpath and -cp. It's probably ignoring the values given by -cp as a result.
Put your own classes ahead of the 3rd-party ones.
You're already in /var/www/var/www/TimetableLoader so keep it simple:-
root#vps5441:/var/www/var/www/TimetableLoader# java -cp .:jsoup-1.8.1.jar:mysql-connector-java-5.0.8/mysql-connector-java-5.0.8-bin.jar TimetableLoader
(Best to get out of the habit of running things as "root" unless you have a genuine need, just sayin')

Raspberry pi - java - Serial Com

I've got a serious problem with my Raspberry Pi (OS: Raspbian) and Java (JDK-7-Armhf). My code wont execute without creating a Exception.
I'll been reading and trying several proposals and nothing have worked yet.
So now i am confused of what went wrong..?
So it goes like this:
I've got a Java source code that will run in my Eclipes IDE.
But when i export the .jar-file, even with library (JRE System lib. _86, JavaSE1.7, JAVAX.comm), as "Runnabel JAR" or just .JAR and execute it om my Raspberry pi, i've got "NoCLassDefFoundExecption: SerialPortEventListener..!
I just don't know why, it won't find the library and use it..!
On my Pi i have librxtx-java installed and JDK-7-oracle-armhf.
librxtx-java should be setting its JAVA_PATH on it's own when installed, but not sure that is done correct!
(I've got a folder /usr/jni and it contains: librxtxSerial.so and
/usr/lib/jvm/jdk-7-oracle-armhf/).
Looking at the library Javax.RXTXcomm in Eclipse, i've got RXTXcomm.jar, that contains SerialPortEventListener, so it is defininated i the .jar.
I'm thinking about, could it be, that there is a missing link between my Java JVM and linux serialport driver? My JRE is working in some way, because it will execute a code to readout HOSTNAME & IP-Adress.
So is there some one who knows how to fix this..?
This is a readout of Java Exception:
Exception in thread "main" java.lang.NoClassDefFoundError: javax/comm/SerialPortEventListener
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:792)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)
Caused by: java.lang.ClassNotFoundException: javax.comm.SerialPortEventListener
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 13 more
A copy of my code. "SimpleRead.java" The original from java comm API samples
You have to change the reference from javax.comm to gnu.io in your source code.
Try following:
Switch to root and run the program you created
If that helps do following
sudo adduser username dialout
then log out and log in from all terminals and GUIs

Conflict between MySQL and mail Java libraries

I have a problem with Java libraries. I'm using javax.mail and mysql-connector.
While compiling I don't have any problems, but if I try to execute the program with sudo:
$sudo java Server -jar mysql-connector-java-5.1.28.jar
It gives me this error:
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:259)
at dbConnect.dbQuery(dbConnect.java:192)
at Server.main(Server.java:39)
while if I try to execute it without sudo:
$java Server -jar mysql-connector-java-5.1.28.jar
It gives me this error:
Exception in thread "main" java.lang.NoClassDefFoundError: javax/mail/internet/AddressException
at dbConnect.registration(dbConnect.java:161)
at dbConnect.splitUsrPass(dbConnect.java:87)
at dbConnect.dbQuery(dbConnect.java:196)
at Server.main(Server.java:39)
Caused by: java.lang.ClassNotFoundException: javax.mail.internet.AddressException
at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 4 more
I can understand why it doesn't work without administrator privileges (I guess the mail library requires them) but it seems strange to me that it won't find the MySQL library if I give it the administrator privileges.
Does anyone know if this is a known issue?
When you want to run something with Java on the command line, you have two options:
Run a class: java MyClass
Run a jar: java -jar MyJar.jar
What you are trying to do is both, which will result in the -jar-part will be ignored.
I'm guessing that what you want to do is run the class Server, with the MySQL-jar on the classpath. The correct command will then be:
java Server -cp mysql-connector-java-5.1.28.jar
You could also add the directory containing the MySQL-jar to the CLASSPATH environment variable. The reason you get different error messages when using sudo and not is probably because the root user has a different CLASSPATH than your user (your user lacks the javax.mail-jar on the classpath, while root has it.)

Run DiscardServer of Netty 4.0 from downloaded source directory

I am trying to run the DiscardServer module of a Maven compiled program called Netty, which I have downloaded as source code. I'm using a GNU/Linux command line terminal to try and follow the instructions in the manual http://netty.io/wiki/user-guide-for-4.x.html.
I'm assuming I should run DiscardServer in directory example/src/main/java, but when I move to that directory and type
$ java -cp "~/norbert/netty-master/all/target/netty-all-5.0.0.Alpha1-SNAPSHOT.jar:~/norbert/netty-master/all/target/netty-all-5.0.0.Alpha1-SNAPSHOT-sources.jar" io.netty.example.discard.DiscardServer
the response is "Error: Could not find or load main class io.netty.example.discard.DiscardServer"
I know the class can be run from a source directory somehow, because
$ java io.netty.example.discard.DiscardServer
produces
Exception in thread "main" java.lang.NoClassDefFoundError: io/netty/channel/EventLoopGroup
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2442)
at java.lang.Class.getMethod0(Class.java:2685)
at java.lang.Class.getMethod(Class.java:1620)
at sun.launcher.LauncherHelper.getMainMethod(LauncherHelper.java:492)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:484)
Caused by: java.lang.ClassNotFoundException: io.netty.channel.EventLoopGroup
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
... 6 more
Having downloaded the binary version netty-4.0.13.Final in addition, I was able to start the discard server in directory netty-4.0.13.Final/jar as follows:
$ java -cp "netty-example-4.0.13.Final.jar:netty-transport-4.0.13.Final.jar:netty-common-4.0.13.Final.jar:netty-buffer-4.0.13.Final.jar" io.netty.example.discard.DiscardServer
How can I run the DiscardServer from directory example/src/main/java or the relevant source directory, though? Thanks, any help would be appreciated.
inside the example folder, you should run:
mvn install
then
mvn exec:java -Dexec.mainClass="io.netty.example.discard.DiscardServer"

running python using jython

I want to run a python function using jython..
Taking the example from this site.
http://sundaycomputing.blogspot.com/2011/01/python-udfs-from-pig-scripts.html
Now when i run the script (pig -f myscript.pig
It returns me this error
Pig Stack Trace
---------------
ERROR 2998: Unhandled internal error. org/python/core/PyException
java.lang.NoClassDefFoundError: org/python/core/PyException
at org.apache.pig.scripting.jython.JythonScriptEngine.registerFunctions(JythonScriptEngine.java:127)
at org.apache.pig.PigServer.registerCode(PigServer.java:567)
at org.apache.pig.tools.grunt.GruntParser.processRegister(GruntParser.java:421)
at org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:419)
at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:188)
at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:164)
at org.apache.pig.tools.grunt.Grunt.exec(Grunt.java:81)
at org.apache.pig.Main.run(Main.java:427)
at org.apache.pig.Main.main(Main.java:108)
Caused by: java.lang.ClassNotFoundException: org.python.core.PyException
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
... 9 more
================================================================================
I am guessing its because of the first line.. REGISTER udf.py USING jython AS udf;
and that I have to specify jython path? (since i am running this code on cluster.. i dont think i have set this thing up)..
Now... since i dont know much of java.. hence switched on python ... but how do i make this code run??
What sort of setup i have to do on my env... to debug this problem.
Thanks
Add $PIG_HOME/lib/jython.jar to your PIG_CLASSPATH environment variable.

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