Eclipse - java lang ClassNotFoundException

Question

When trying to start my JUnit-Test out of Eclipse  I get a  ClassNotFoundException   When running  mvn test  from console - everything works fine  Also  there are no problems reported in Eclipse   My project structure is the following    parent project  pom-packaging    Web project  war-packaging - my JUnit-test is in here  Flex project Configuration project      edit  How can the class not be found  It s a simple HelloWorld-Application with no special libraries   Here s my JUnit s run-configuration  alt text http   www walkner biz  temp runconfig png    Testclass  but as I said  it doesn t work with a simple HelloWorld either       import org junit After  import org junit Assert  import org junit Before  import org junit Test  import org springframework context ApplicationContext  import org springframework context support ClassPathXmlApplicationContext  import biz prognoserechnung domain User  import biz prognoserechnung domain UserRepository  import biz prognoserechnung domain hibernate UserHibernateDao   public class UserDaoTest          the applicationcontext      private ApplicationContext ctx   null          the user itself      private User record   null          Interface for the user      private UserRepository dao   null    Before public void setUp   throws Exception   String   paths      WEB-INF applicationContext xml     ctx   new ClassPathXmlApplicationContext paths   dao    UserHibernateDao  ctx getBean  userRepository        After public void tearDown   throws Exception   dao   null      Test public final void testIsUser   throws Exception   Assert assertTrue dao isUser  John    Doe         Test     public final void testIsNoUser   throws Exception       Assert assertFalse dao isUser  not    existing             Assert assertFalse dao isUser null  null            Assert assertFalse dao isUser

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The problem might be missing the class file in your build folder  One solution is clean the project and rebuild it

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Hmm  looks a little bizarre  try running it with the following annotation at the top of the class    RunWith SpringJUnit4ClassRunner class  public class UserDaoTest       and let me know how you get on with it       Check that you have build automatically enabled as well   If you want to make sure your test classes are being compiled correctly clear out the Maven target folder  and any bin folder that Eclipse may be using    Are you using m2eclipse as well  as I find it to be a little problematic

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Furthermore  DOUBLE-CHECK the eclipse  Web Deployment Assembly  dialog     This can be found  Project Properties- Deployment Assembly      Recently I had an eclipse plugin modify one of my web projects  and it added  mysteriously  added  the maven test directories   src test java   src test resources to the Deployment Assembly    UGGGG        Which is why my project worked fine when I built  amp  deployed just straight maven to tomcat  no ClassNotFoundExceptions     However  when I did the deploy through Eclipse  Whammo   I start getting ClassNotFoundExceptions because the TestCode is getting deployed     Eric

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Well  you can solve this problem basically by creating a new project   Close the project  save the code in another folder on your computer   Create a new project  add a new final directory and do not leave the default directory selected   Remake your previous project adding the code saved before   This happens because probably you created a project and didn t select a directory folder or something like that  I hope had helped you

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The solution to my problem which was similar  the libs were invalid  If you look in the  classpath file of the project  you ll see classpathentry tags with the key value kind  lib   Some of mine were incorrect   I didn t discover this until I turned off Validation settings  That is  there were so many errors in the JSP files  etc  that the classpath errors weren t evident  or possibly even showing up   As a result  nothing was being compiled into the destination output folders  but no helpful errors on why

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Its very Old  Jul  which year  but I had the same problem     Actual issue found that eclipse was not able to generate class file for the java file   classpath was proper    See the problem tab and check if your project is missing something file   you can create a new proj and add files one by one and build them until it stops compiling  and creating classes   check the workspace proj bin package   folder for classes    its wierd but true   ecplise was failing in compliation because 4 of 20 java files were using a single image which was missing  and as result none of the java file was compiled     CLASSPATH is not a issue here

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Go To Build Path -  Source and toggle to Yes option  Ignore Optional Compile Problems  for all source folders

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Sachin s right  Even with correct class path  the problems tab will show that some dependency or the Resource project has error that needs to be fixed in order for maven to automatically build and create classes when you create or make a change in your test class    Hi   Its very Old Jul  which year  but I had the same problem    Actual issue found that eclipse was not able to generate class file for the java file   classpath was proper   See the problem tab and check if your project is missing something file  you can create a new proj and add files one by one and build them until it stops compiling and creating classes   check the workspace proj bin package  folder for classes    its wierd but true   ecplise was failing in compliation because 4 of 20 java files were using a single image which was missing  and as result none of the java file was compiled    CLASSPATH is not a issue here

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while running web applications Most of us will get this Exception  When you got this error you have place  class files in proper folder    In web applications all  class files should sit in WEB-INF Classes folder  if you are running web app in Eclipse please follow the steps  Step 1  Right click on Project folder and Select Properties Step 2  Click on  Java Build Path  you will see different tabs like  source     projects    libraries  etc Step 3  select Source folder  under this you will see your project details Step 4  in the  Source  folder you will see Default Output Folder option  here you have to give the classes folder under WEB-INF  just give the path like projectname WebContent WEB-INF classes the structure depends on your application please do remember here you no need to create  classes  folder  Eclipse will create it for you  Step 5  click on  OK  and do the project clean and Build  that s it your app will run now

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I had the exact same problem but I figured it out  Go to your project file and right click on it  then click Refresh or hit F5  Then try and run it   If it still doesn t work then just forget it  as I had the EXACT same problem and it just means you version of Eclipse is garbage

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I faced the same problem  for me the issue is different  It came because some of the maven dependencies are not downloaded    a  I went through properties - gt  Java Buildpath - gt  Maven Dependencies and identified the missed libraries   b  Removed the missed libraries artifacts from pom xml c  Downloaded the libraries and added them explicitly

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I had the same problem  All what I did was    i   Generated Eclipse artifacts   mvn clean eclipse eclipse  ii   Refresh the project and rerun your junit test  Should work fine

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Enabling  x  Use temporary JAR to specify classpath  to avoid classpath length limitations  inside the Classpath tab of the Run configuration did the trick for me   If your project is huge and you have lots of dependencies from other sibling projects and maven dependencies  you might hit the classpath length limitations and this seems to be the only solution  apart from making the directory to you local maven repo shorter  ours already starts at c  m2

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Make sure if your test class working before   but you facing issue all of sudden  then clean your project and build it again  Make sure project has been configured in build path as read above article

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I was hit with this issue also and was able to come up with a sufficient solution for my case   If your Eclipse project has a  classpath file in your project root  see it in Navigator view instead of Package Explorer view   be sure that your Maven classpathentry appears prior to your JRE Container classpathentry    lt  xml version  1 0  encoding  UTF-8   gt   lt classpath gt       lt classpathentry kind  con  path  org maven ide eclipse MAVEN2 CLASSPATH CONTAINER   gt       lt classpathentry kind  con  path  org eclipse jdt launching JRE CONTAINER   gt   lt  classpath gt    If your project does not have a  classpath file  you can edit your project s Java Build Path to switch the Order and Export   If your project has the  classpath file and you only change your ordering in the Java Build Path  you will see that the ordering is not impacted and the issue will continue to occur   And a project- clean never hurts things after you make the change

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Tried   Link    here  1   Open your run configurations Click on the jUnit-Test you want to start go to the classpath tab Try to add a folder  click on user entries  click on advanced  click on add folders click on ok and search the outputfolder for your test classes those you find under projektproperties java build path  source     worked after   Maven 2 LifeCycle    test

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I am using gradle with eclipse and faced the same challenge today and tried a number of ways to resolve but the only way which helped me was to run command gradlew clean        P S     Don t combine the  build  with the above mentioned command    Helped me  try your luck

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Usually this problem occurs while running java application java tool unable to find the class file       Mostly in maven project we see this issue because Eclipse-Maven sync issue  To solve this problem  Maven- Update Configuration

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JUnit test from inside eclipse gave me also NoClassDefFoundError  Running  mvn clean test  from command line gave me following error on several jars  invalid LOC header  bad signature  Deleting these jars from local m2 repository and running  mvn clean test  again solved my problem

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Changing the order of classpath artifacts in the Java Build Path resolved it for me    Right Click on the project and go to Project Build path  Go to  Order and Export tab and move the JRE system library to after the sources    This should fix it

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Run project as Maven test  then Run as JUnit Test

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Deleting the project from eclipse  Not from hard disk  which in a way is cleaning the workspace and reimporting the project into eclipse again worked for me

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That means your pom xml has unresolved issues  Open the problems view solve accordingly  Then you will be able to run the test cases successfully without encountering the classnotfoundexception

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I tried everything I read in this long post and  incredibly  what worked for me was  rather than clicking on the test class and selecting Run as JUnit test  clicking on the test method and running as JUnit test  I have no idea why

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There are many convoluted suggestions here   I ve encountered this problem multiple times with Maven projects after moving resources around by drag  n  drop  or performing refactoring of class names   If this occurs  simply copy  not move  the problem Test Case   java  via terminal file browser to another location  right-click - gt  Delete in Eclipse and choose to delete on disk when given the option  move copy the copied file to the original file location  then select your project in Eclipse and press F5 to refresh resources   This is quick and easy to do  and has fixed the problem permanently for me every time

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I have see Eclipse - java lang ClassNotFoundException when running junit tests   I had deleted one of the external jar files which was added to the project  After removing the reference of this jar file to the project from Eclipse  i could run the Junit tests

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This was my solution to the problem  Of course  many things can cause it to occur  For me it was that Maven2  not the plugin for Eclipse  was setting the eclipse profile up to use a different builder  aspectJ  but I did not have the plugin in eclipse    http   rbtech blogspot com 2009 09 eclipse-galileo-javalangclassnotfoundex html  Cheers Ramon Buckland

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All I did was Properties -  Java Build Path -  Order and Export -  Enabled all unchecked boxes -  moved Junit all the way up

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click on project- gt properties- gt Java build path- gt Source and check each src folder is still valid exist or recently removed  Correct any missing path or incorrect path and rebuild and run the test  It will fix the problem

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I had tried all of the solutions on this page  refresh project  rebuild  all projects clean  restart Eclipse  re-import  even  the projects  rebuild maven and refresh   Nothing worked   What did work was copying the class to a new name which runs fine -- bizarre but true   After putting up with this for some time  I just fixed it by    Via the Run menu Select Run Configurations Choose the run configuration that is associated with your unit test  Removing the entry from the Run Configuration by pressing delete or clicking the red X    Something must have been screwed up with the cached run configuration

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your build classpath is correct  which is why you can compile   the classpath for your JUnit needs to be checked   go to the Run menu and choose  open run dialog    in there you should see a tree on the left with JUnit as an option   open that node and find and select your test   on the right pane you will see a tab for classpath   take a look to ensure that your class that the test is trying to instantiate would be found   edit   this seems to be an issue with maven and its behavior after a release changed the default Eclipse output folders   i have seen solutions described where    placing maven into the bootclasspath ABOVE the jre works  or  running mvn clean test does the trick or  refreshing all of your eclipse projects  causing a rebuild fixes the problem going to your project and selecting Maven- Update Configuration solve the problem   with the first three  there were reports of the issue recurring   the last looks best to me  but if it doesnt work  please try the others   here and here is some info

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Please point to correct JDK from Windows   Preferences   Java   Installed JRE   Do not point to jre  point to a proper JDK  I pointed to JDK 1 6U29 and refreshed the project   Hereafter  the issue is gone and jUnit Tests are working fine   Thanks   -Tapas

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I ve run into a same error in Eclipse recently  i e   the Eclipse IDE couldn t find the Unit test class no matter how I change the configurations  Learning from the previous posts here and in other web sites  I ve double checked and triple checked the classpath and source info  and move up and down the source folder and libraries  in both the  Run Configuration  and the  Java Build Path  config windows  and I ve also cleaned the Project and rebuilt it  but none of the tricks work for me  The specific Java project is an old ANT compiled project and have lots of jars included in Eclipse library   Then  I changed the unit test class to add a main   method and right click it to  Run As  a Java Application instead of JUnit test  and suddenly  Eclipse seems to wake up and identified the class correctly  Afterwards  I switched it back to a Unit test application  and it is still working   This seems to be a bug in Eclipse  I am guessing the large number of libraries   260  may confused the JVM s ability to locate my JUnit class

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JUnit 4 4 is not supported by the JMockit JUnit integration  Only versions 4 5 or newer are supported that

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I suggest trying adding this to the VM arguments  -verbose class -verbose module -Xdiag  Then you can debug it from Eclipse which should print out some message like  java lang ClassNotFoundException  org adligo somewhere Foo     at java base java lang ClassLoader loadClass ClassLoader java 521      at java base java lang Class forName0 Native Method      at java base java lang Class forName Class java 398      at java base sun launcher LauncherHelper loadMainClass LauncherHelper java 760      at java base sun launcher LauncherHelper checkAndLoadMain LauncherHelper java 655   From this you can set a breakpoint on LancherHelper java 760 to debug the Eclipse Lanucher itself   In my case I noticed that user classpath appeared to be null  even though I have many jars in it in the Lanuch config

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Carlos approach helped  Eclipse - java lang ClassNotFoundException  Try to check the classpath of the junit run configuration    Open your run configurations Click on the jUnit-Test you want to start go to the classpath tab Try to add a folder  click on user entries  click on advanced  click on add folders  click on ok and search the outputfolder for your test classes those you find under projektproperties java build path  source     works for me

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We had the exact exception  using SpringSource Tools  tomcat  on Win7  and the cause was that we had refactored a filename  renamed a file  from SubDomain java to Subdomain java  D vs d  and somehow it collided though SpringSource was showing the new name Subdomain java  The solution was to delete the file  via SpringSource  and create it again under the name Subdomain java and copy-pasting its former content  Simple as that

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Make sure your test launch configuration does NOT contain the following lines  OR try enabling automated Maven dependency management    lt stringAttribute key  org eclipse jdt launching CLASSPATH PROVIDER  value  org maven ide eclipse launchconfig classpathProvider   gt   lt stringAttribute key  org eclipse jdt launching SOURCE PATH PROVIDER  value  org maven ide eclipse launchconfig sourcepathProvider   gt

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I ve come across that situation several times and  after a lot of attempts  I found the solution   Check your project build-path and enable specific output folders for each folder  Go one by one though each source-folder of your project and set the output folder that maven would use    For example  your web project s src main java should have target classes under the web project  test classes should have target test-classes also under the web project and so   Using this configuration will allow you to execute unit tests in eclipse   Just one more advice  if your web project s tests require some configuration files that are under the resources  be sure to include that folder as a source folder and to make the proper build-path configuration   Hope it helps

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I solve that Bulit path--- libraries--- add library--- Junit  check junit4

[java] Eclipse - java.lang.ClassNotFoundException

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