java linux server: class not found exception though jar in classpath - java

Im running a Java application on an Amazon EC2 instance which is a linux server. I included a json jar in the build path and I checked the class path and it's there. When I import the class
import org.json.JSONException;
import org.json.JSONObject;
I dont get any compilation errors, but when I execute my app I get the ClassNotFoundException.
Exception in thread "Thread-1" java.lang.NoClassDefFoundError: org/json/JSONException
at Group.run(Group.java:62)
at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.ClassNotFoundException: org.json.JSONException
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)
Does anybody know how to fix it?
I have tried to fix this for weeks now, I'm really frustrated!

I think it may be the environment setting problem.
Try to edit ~/.bash_profile and append the CLASSPATH value like:
CLASSPATH=$CLASSPATH:/your/jar/folder/
export CLASSPATH
Then using following cmd to make the setting work:
source ~/.bash_profile

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

How to use classpath in ubuntu terminal for executing java class?

I tried to execute CreateTextFileTest.class file with classpath in the terminal as the following:
java -classpath ..:"/home/fatih/NetBeansProjects/Unit17 - CreatingTextFile/src/unit17/unit17/creatingtextfile" CreateTextFileTest
My class files in this directory : /home/fatih/NetBeansProjects/Unit17 - CreatingTextFile/src/unit17/unit17/creatingtextfile .
I have 3 classes in the directory: AccountRecord.class , CreateTextFile.class, and CreateTextFileTest.class
But, when I executed the CreateTextFileTest from the terminal with the code above, an error occured like that:
Exception in thread "main" java.lang.NoClassDefFoundError: CreateTextFileTest (**wrong name**: unit17/creatingtextfile/CreateTextFileTest)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
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$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)
As far as I understand because CreateTextFileTest.java uses two different classes, executing fails. How to handle this situation? How to run my java project? How to use classpath in this situation? Am I using wrongly?
The error message states that the package name declared in your compiled class doesn't match what the JVM was expecting given your classpath setup. The classpath should point to the directory from which your packages start, not the directory actually containing your .class files. Given your error message I believe that this should work:
java -classpath ..:"/home/fatih/NetBeansProjects/Unit17 - CreatingTextFile/src/unit17" unit17.creatingtextfile.CreateTextFileTest
Given the duplicate unit17 in your path I get the impression there's something else mixed up here. You'll get a better answer on Stack Overflow...

Java running code from command line

I'm on Mac OS X 10.9.2 (Mavericks). I have code that uses an external Java library (twitter4j). It runs fine when I run it through NetBeans. However, trying to run almost identical code in the terminal gives me errors.
My directory structure is straightforward- I have a 'src' folder with the .java file and a 'lib' folder with the external .jar files I use.
From the src folder, I call javac -cp "../lib/*" MyProgram.java which seems to work alright. Now, if I call java MyProgram, I get an exception:
Exception in thread "main" java.lang.NoClassDefFoundError: twitter4j/StreamListener
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2693)
at java.lang.Class.privateGetMethodRecursive(Class.java:3040)
at java.lang.Class.getMethod0(Class.java:3010)
at java.lang.Class.getMethod(Class.java:1776)
at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)
Caused by: java.lang.ClassNotFoundException: twitter4j.StreamListener
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)
It seems to have trouble properly importing the external twitter4j library. What am I missing here?
These are my import statements in the code:
import twitter4j.*;, import twitter4j.conf.ConfigurationBuilder;
UPDATE: Using suggestions below, I also tried running it via java -cp "../lib/*" MyProgram which gives: "Could not find or load main class MyProgram"
You need to specify the classpath when running the program as well as when compiling it:
E.g.
java -cp "../lib/*" MyProgram

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.)

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