I am trying to use JDBC to access the MySql database on my computer. I get this error message
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
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:191)
at FunctionClass.special_function(FunctionClass.java:72)
at FunctionClass.<init>(FunctionClass.java:25)
at EvaluateFunctions.main(EvaluateFunctions.java:12)
I've seen on the other posts that this is due to the fact that the driver is not in the lib directory of the JDK. I tried that and it still doesn't work. I added the *.jar file to my "/usr/lib/default-java/lib/" folder on Xubuntu. I am not using any kind of servers. Here is my code that connects to the database:
Class.forName("com.mysql.jdbc.Driver");
Does anyone know what I am missing here?
Thanks for all the help in advance.
If you are using eclipse or some ide you can add the jar files to your build path.
It can be done by checking this link for eclipse. https://stackoverflow.com/a/27085441/4083590
If you are using command prompt you should add the jar files to your CLASSPATH. It can be done as shown below.
Linux:
CLASSPATH=$CLASSPATH;{Current working directory};{Direct Path to .jar file}
CLASSPATH=$CLASSPATH;/home/users/xyz/workspace/;/home/users/xyz/workspace/xyz.jar
Note: ./ can be used to signify current working directory
Windows:
set CLASSPATH=%CLASSPATH%:{Current working directory}:{Direct path to .jar file}
set CLASSPATH=%CLASSPATH%:C:\users\xyz\workspace:C:\users\xyz\workspace\xyz.jar
After doing this you would be able to compile your program.
Related
I know almost nothing about Java so please take it easy on me. I'm using this plugin, which I've had working nicely for a few days on my Mac (following the repo's very simple instructions below), but when I took it to an Ubuntu instance I got the following error:
ResumeParser/ResumeTransducer$ java -cp 'bin/*:../GATEFiles/lib/*:../GATEFILES/bin/gate.jar:lib/*' code4goal.antony.resumeparser.ResumeParserProgram somefile.pdf somefile.json
Exception in thread "main" java.lang.NoClassDefFoundError: gate/SimpleAnnotation
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2625)
at java.lang.Class.getMethod0(Class.java:2866)
at java.lang.Class.getMethod(Class.java:1676)
at sun.launcher.LauncherHelper.getMainMethod(LauncherHelper.java:494)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:486)
Caused by: java.lang.ClassNotFoundException: gate.SimpleAnnotation
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)
... 6 more
Anyone have thoughts on what is going wrong?
Installation and usage instructions:
1. git clone https://github.com/antonydeepak/ResumeParser.git
2. cd ResumeParser/ResumeTransducer
3. export GATE_HOME="..\GATEFiles"
Paths are case sensitive in Ubuntu, GATEFiles is different from GATEFILES. Since gate.SimpleAnnotation is in gate.jar, I bet that your classpath should be:
-cp 'bin/:../GATEFiles/lib/:../GATEFiles/bin/gate.jar:lib/*'
Disclaimer: I haven't used this plugin, I don't know if the other parts of the classpath are correct.
In general, you can "debug" by trying
ls ../GATEFiles/bin/
to see if there is a gate.jar file.
It's hard to know, but most likely the class it cannot find is in the gate.jar file, and it is either not on the new machine, or is not in the correct place on the new machine.
To expand slightly: Classes are found in a couple of places, but you specify a gate.jar on the classpath of the command line (that's what the -cp designates), so I'm guessing it's there. Since java can't find it, I'm guessing further that the necessary jar file is not where it needs to be for the Java runtime to find it.
For Linux and OSX use '/' and ':' , try this call .. it worked for me
java -cp './bin/*:../GATEFiles/lib/*:../GATEFiles/bin/gate.jar:./lib/*' code4goal.antony.resumeparser.ResumeParserProgram cv.pdf cv.json
I am trying to get rid of some NoClassDefFoundError due to some jars not found at run time. So I put in my hdfs system some lib and I call and I put this
String lib = "/path/to/lib";
Path hdfsJar = new Path(lib);
DistributedCache.addFileToClassPath(hdfsJar, conf);
Now, I am still getting the error. However, if I set the jars in the $HADOOP_CLASSPATH. Am I doing wrong with the DistributedCache call ?
edit :
java.lang.RuntimeException: java.lang.NoClassDefFoundError: gov/nih/nlm/nls/metamap/MetaMapApi
at org.apache.hadoop.mapreduce.lib.chain.Chain.joinAllThreads(Chain.java:526)
at org.apache.hadoop.mapreduce.lib.chain.ChainMapper.run(ChainMapper.java:169)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:784)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:341)
at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:163)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1628)
at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158)
Caused by: java.lang.NoClassDefFoundError: gov/nih/nlm/nls/metamap/MetaMapApi
at org.avrosation.metamap.ChainMetaProcess$TokenizerMapper.map(ChainMetaProcess.java:25)
at org.avrosation.metamap.ChainMetaProcess$TokenizerMapper.map(ChainMetaProcess.java:16)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:145)
at org.apache.hadoop.mapreduce.lib.chain.Chain$MapRunner.run(Chain.java:321)
Caused by: java.lang.ClassNotFoundException: gov.nih.nlm.nls.metamap.MetaMapApi
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)
Try providing fully qualified HDFS path. try below code:
Make sure you upload jar to HDFS (any location on hdfs, i am assuming /tmp).
hadoop fs -copyFromLocal my.jar /tmp
Then edit your java code like :
String lib = "hdfs://localhost:9000/tmp/my.jar";
Path hdfsJar = new Path(lib);
DistributedCache.addFileToClassPath(hdfsJar, conf);
This doc detail about distributed cache : https://hadoop.apache.org/docs/stable/api/org/apache/hadoop/filecache/DistributedCache.html
In fact, I suspected from the beginning some problem with my ide IntelliJ Idea 14 because I had to deal with a major refactoring of the code which then made the code reveal the issue. To begin I tried to clean the building with no success, then I simply created an other project and copy-pasted the classes and libraries' import and that made the trick !
I'm writing a java app and running it on a linux ec2 server.
the program was running fluently yesterday, and after I changed and organazied some files and packages I'm getting this problem when I execute the program:
I'm running the programm with this command:
java -cp . main.Server
And get the following error:
Exception in thread "Thread-0" java.lang.NoClassDefFoundError: org/json/JSONObject
at main.Group.<init>(Group.java:28)
at main.Server.run(Server.java:23)
Caused by: java.lang.ClassNotFoundException: org.json.JSONObject
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)
... 2 more
I was running the programm as this before the changes:
export CLASSPATH=$CLASSPATH:/home/ec2-user/java-json.jar
In the bin folder, command:
java Server
And the programm was running.
Since I changed the package from default name to main, I need to run it with the command java -cp . main.Server, but I get the error written above.
I also tried modifing the .bash_profile and add this:
CLASSPATH=$CLASSPATH:/home/ec2-user/java-json.jar
export CLASSPATH
But it didn't help.
I have no errors in my code and the jar is not broken since it worked before. What should I do to fix this problem?
Specify the jar file on the classpath like this:
java -cp .:/home/ec2-user/java-json.jar main.Server
If your classpath is indeed correctly set in your .bash_profile, you could also do:
java -cp .:$CLASSPATH main.Server
I am trying to perform map reduce on Pentaho 5. For Pentaho 5, the Pentaho applications come pre-configured for Apache Hadoop 0.20.2 and it says no further configuration is required for this version. I installed Hadoop 0.20.2 on windows using cygwin and every thing works fine. I run a simple job on Pentaho, which copies file in HDFS which finished successfully and the file system was copied into HDFS. But as soon as I run map reduce job, it says the job was finished on pentaho but the map reduce task was failed and on the output directory on HDFS the result is missing and the log file says:
Error: java.lang.ClassNotFoundException: org.pentaho.di.trans.step.RowListener
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)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:270)
at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:762)
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:807)
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:833)
at org.apache.hadoop.mapred.JobConf.getMapRunnerClass(JobConf.java:790)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:354)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:307)
at org.apache.hadoop.mapred.Child.main(Child.java:170
Please Help me out.
Maybe a little bit old but I thought it might help someone.
This can be caused by:
For Hadoop version > 0.20: check if you set up your environment correctly, see Pentaho Support : Creating a New Hadoop Configuration
Check on HDFS if you have an /opt/pentaho/mapreduce/ and check folder permissions on HDFS for /opt/pentaho (Did you find the kettle-*.jar files in lib folder?)
Check classpath separator ("," in Windows, ":" in Linux). In order to change it, edit spoon.sh (or spoon.bat) and modify OPT variable like this: OPT="$OPT -Dhadoop.cluster.path.separator=,"
I am getting the following error
Exception in thread "main" java.lang.NoClassDefFoundError: org/jsoup/Jsoup
at Main.main(Main.java:42)
Caused by: java.lang.ClassNotFoundException: org.jsoup.Jsoup
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
... 1 more
Now what I have done so far:
I created a libs folder in my project folder and added the Jsoup.jar there. Then in eclipse I click properties, add external Jar and added it. I see the referenced library.
But the issue still persist. I dont get compilation errors. So this is a runtime issue. Appreciate the help.
Edit:
I have found the following
If I compile using
javac -classpath /path/to/jsoup.jar myclass.java
and then
java -classpath /path/to/jsoup.jar myclass
It runs perfect.
Now. This is not working for me because I am going to use my application on a computer that does not have Jsoup. So how to I resolve this runtime issue?
Go to Run configurations... menu and check classpath for Run task. It looks like you add library for Compilation step, but it doesn't set at Run step.
Edit (after comment)
I dove into the issue and found that this dependency is needed for application container. So you just need to add this library to classpath of your app server. If you use Tomcat, just put the library to the %CATALINA_HOME%\lib directory.