How to solve java lang NoClassDefFoundError

Question

I ve tried both the example in Oracle s Java Tutorials  They both compile fine  but at run-time  both come up with this error   Exception in thread  main  java lang NoClassDefFoundError  graphics shapes Square     at Main main Main java 7  Caused by  java lang ClassNotFoundException  graphics shapes Square     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          1 more   I think I might have the Main java file in the wrong folder  Here is the directory hierarchy   graphics   Main java   shapes       Square java       Triangle java   linepoint       Line java       Point java   spaceobjects       Cube java       RectPrism java   And here is Main java   import graphics shapes    import graphics linepoint   import graphics spaceobjects     public class Main       public static void main String args              Square s   new Square 2 3 15           Line l   new Line 1 5 2 3           Cube c   new Cube 13 32 22             What am I doing wrong here   UPDATE  After I put put the Main class into the graphics package  I added package graphics  to it   set the classpath to   test   folder containing graphics   compiled it  and ran it using java graphics Main  from the command line   it worked   Really late UPDATE  2  I wasn t using Eclipse  just Notepad   and the JDK   and the above update solved my problem  However  it seems that many of these answers are for Eclipse and IntelliJ  but they have similar concepts

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After you compile your code  you end up with  class files for each class in your program  These binary files are the bytecode that Java interprets to execute your program  The NoClassDefFoundError indicates that the classloader  in this case java net URLClassLoader   which is responsible for dynamically loading classes  cannot find the  class file for the class that you re trying to use    Your code wouldn t compile if the required classes weren t present  unless classes are loaded with reflection   so usually this exception means that your classpath doesn t include the required classes  Remember that the classloader  specifically java net URLClassLoader  will look for classes in package a b c in folder a b c  in each entry in your classpath  NoClassDefFoundError can also indicate that you re missing a transitive dependency of a  jar file that you ve compiled against and you re trying to use   For example  if you had a class com example Foo  after compiling you would have a class file Foo class  Say for example your working directory is     project   That class file must be placed in     project com example  and you would set your classpath to     project    Side note  I would recommend taking advantage of the amazing tooling that exists for Java and JVM languages  Modern IDE s like Eclipse and IDEA and build management tools like Maven or Gradle will help you not have to worry about classpaths  as much  and focus on the code  That said  this link explains how to set the classpath when you execute on the command line

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NoClassDefFoundError in Java   Definition    NoClassDefFoundError will come if a class was present during compile time but not available in java classpath during runtime  Normally you will see below line in log when you get NoClassDefFoundError  Exception in thread  main  java lang NoClassDefFoundError  Possible Causes    The class is not available in Java Classpath  You might be running your program using jar command and class was not defined in manifest file s ClassPath attribute  Any start-up script is overriding Classpath environment variable  Because NoClassDefFoundError is a subclass of java lang LinkageError it can also come if one of it dependency like native library may not available  Check for java lang ExceptionInInitializerError in your log file  NoClassDefFoundError due to the failure of static initialization is quite common  If you are working in J2EE environment than the visibility of Class among multiple Classloader can also cause java lang NoClassDefFoundError  see examples and scenario section for detailed discussion    Possible Resolutions    Verify that all required Java classes are included in the application   s classpath  The most common mistake is not to include all the necessary classes  before starting to execute a Java application that has dependencies on some external libraries  The classpath of the application is correct  but the Classpath environment variable is overridden before the application   s execution  Verify that the aforementioned ExceptionInInitializerError does not appear in the stack trace of your application    Resources    3 ways to solve java lang NoClassDefFoundError in Java J2EE  java lang NoClassDefFoundError     How to solve No Class Def Found Error

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In my environment  I encounter this issue in unit test  After appending one library dependency to   pom  that s fixed   e g    error message   java lang NoClassDefFoundError  com abc def foo xyz Iottt   pom     lt dependency gt       lt groupId gt com abc def lt  groupId gt       lt artifactId gt foo lt  artifactId gt       lt scope gt test lt  scope gt   lt  dependency gt

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No Class Definition Exception occurs when the intended class is not found in the Class Path  At Compile Time Class   Class was generated from Java Compiler  But Somehow at Run Time the Dependent Class is not found   Lets go through one Simple Example    public class ClassA  public static void main String args            Some gibberish Code         String text   ClassB getString         System out println  Text is      text          public class ClassB      public static String getString          return  Testing Some Exception          Now Lets assume that the above two Java Source Code are placed in some Folder let say  NoClassDefinationFoundExceptionDemo   Now open a shell Assuming Java is already being setup correctly    Go to Folder  NoClassDefinationFoundExceptionDemo  Compile Java Source Files  javac ClassB  javac ClassA Both Files are Compiled Sucessfully and generated Class files in the same    Folder as ClassA class and ClassB class Now Since we are overiding ClassPath to current working directory therefore we execute the following command java -cp   ClassA and It worked Successfully and you will see the Output in the screen Now Lets say  You removed  ClassB class file from Present Directory  and now you execute the command again  java -cp   ClassA Now it will greet you with NoClassDefFoundException  as ClassB which is a dependency for ClassA is not found in the classpath i e present working directory

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After working on a NetBeans project for many months  I suddenly got the NoClassDefFoundError message shortly after getting a  Low Memory  alert  Doing a Clean rebuild didn t help  but closing Netbeans altogether and reopening the project there were no error reports

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For my project  what solved the issue was that Chrome browser and chromedriver were not compatibles  I had a very old version of the driver that could not even open the browser  I just downloaded the latest version of both and problem solved  How did I discovered the issue  Because I ran my project using the Selenium native firefox driver with an old version of FF inculded with my application  I realized then that the problem was incompatibility of between browser and driver   Hope this can help anyone with a similiar issue as mine  that generated this same Error Message

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For Meteor or Cordova users  It can be caused by the Java version you use  for meteor and cordova stick with version 8 for now  1- Check available Java versions  usr libexec java home -V  and look for the path name for Java version 8 2- Set the path for Java version 8 export JAVA HOME  Library Java JavaVirtualMachines jdk1 8 0 191 jdk Contents Home 3- Check if it is done echo  JAVA HOME Go on and contiune coding

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I m developing an Eclipse based application also known as RCP  Rich Client Platform   And I have been facing this problem after refactoring  moving one class from an plugIn to a new one    Cleaning the project and Maven update didn t help   The problem was caused by the Bundle-Activator which haven t been updated automatically  Manual update of the Bundle-Activator under MANIFEST MF in the new PlugIn has fixed my problem

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It happens a lot with my genymotion devices  Make sure you have a good amount of memory available on your drive where Genymotion is installed

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if you got one of these error while compiling and running     NoClassDefFoundError    Error  Could not find or load main class hello    Exception in thread  main  java lang NoClassDefFoundError javaTest test hello   wrong name  test hello          at java lang ClassLoader defineClass1 Native Method          at java lang ClassLoader defineClass Unknown Source          at java security SecureClassLoader defineClass Unknown Source          at java net URLClassLoader defineClass Unknown Source          at java net URLClassLoader access 100 Unknown Source          at java net URLClassLoader 1 run Unknown Source          at java net URLClassLoader 1 run Unknown Source          at java security AccessController doPrivileged Native Method          at java net URLClassLoader findClass Unknown Source          at java lang ClassLoader loadClass Unknown Source          at sun misc Launcher AppClassLoader loadClass Unknown Source          at java lang ClassLoader loadClass Unknown Source          at sun launcher LauncherHelper checkAndLoadMain Unknown Source    -------------------------- SOLUTIION -----------------------  the problem is mostly in packages organization  You should arrange your classes in folders properly regarding to the package classifications in your source code   On Compiling process use this command   javac -d    FileName java   To Run the class please use this command   java  Package   ClassName

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java lang NoClassDefFoundError   indicates  that something was found at compiletime but not at runtime  maybe you just have to add it to the classpath

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I had the same issue with my Android development using Android studio  Solutions provided are general and did not help me   at least for me   After hours of research I found following solution and may help to android developers who are doing development using android studio  modify the setting as below Preferences - Build  Execution  Deployment -  Instant Run -  un-check the first option   With this change I am up and running   Hope this will help my dev friends

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if you recently added multidex support in android studio like this      To Support MultiDex implementation  com android support multidex 1 0 1    so your solution is just extend From MultiDexApplication instead of Application  public class MyApp extends MultiDexApplication

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This answer is specific to a java lang NoClassDefFoundError happening in a service   My team recently saw this error after upgrading an rpm that supplied a service   The rpm and the software inside of it had been built with Maven  so it seemed that we had a compile time dependency that had just not gotten included in the rpm     However  when investigating  the class that was not found was in the same module as several of the classes in the stack trace   Furthermore  this was not a module that had only been recently added to the build   These facts indicated it might not be a Maven dependency issue   The eventual solution  Restart the service   It appears that the rpm upgrade invalidated the service s file handle on the underlying jar file   The service then saw a class that had not been loaded into memory  searched for it among its list of jar file handles  and failed to find it because the file handle that it could load the class from had been invalidated   Restarting the service forced it to reload all of its file handles  which then allowed it to load that class that had not been found in memory right after the rpm upgrade   Hope that specific case helps someone

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This error means you didn t add some of dependencies

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Don t use test classes outside the module  I do not have a solution  just another flavour of the  present at compilation  absent at run time  case   I was trying to use a very convenient method from a JUnit test class from another test class which resides in a different module  That s a no-no  since test code is not part of the packaged jar  but I didn t realize because it appears visible for the user class from within Eclipse   My solution was to place the method in a existing utilities class that is part of the production code

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NoClassDefFoundError means that the class is present in the classpath at Compile time  but it doesn t exist in the classpath at Runtime   If you re using Eclipse  make sure you have the shapes  linepoints and the spaceobjects as entries in the  classpath file

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My two cents in this chain   Ensure that the classpath contains full paths   home user lib some lib jar instead of   lib some lib jar  otherwise you can still face NoClassDefFoundError error

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I have faced with the problem today  I have an Android project and after enabling multidex the project wouldn t start anymore   The reason was that I had forgotten to call the specific multidex method that should be added to the Application class and invoked before everything else    MultiDex install this     Follow this tutorial to enable multidex correctly  https   developer android com studio build multidex html  You should add these lines to your Application class    Override   protected void attachBaseContext Context base         super attachBaseContext base        MultiDex install this

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I get NoClassFoundError when classes loaded by the runtime class loader cannot access classes already loaded by the java rootloader   Because the different class loaders are in different security domains  according to java  the jvm won t allow classes already loaded by the rootloader to be resolved in the runtime loader address space   Run your program with  java -javaagent tracer jar  YOUR java ARGS    It produces output showing the loaded class  and the loader env that loaded the class   It s very helpful tracing why a class cannot be resolved      ClassLoaderTracer java    From  https   blogs oracle com sundararajan entry tracing class loading 1 5  import java lang instrument    import java security        manifest mf    Premain-Class  ClassLoadTracer     jar -cvfm tracer jar manifest mf ClassLoaderTracer class     java -javaagent tracer jar         public class ClassLoadTracer        public static void premain String agentArgs  Instrumentation inst                 final java io PrintStream out   System out          inst addTransformer new ClassFileTransformer                 public byte   transform ClassLoader loader  String className  Class classBeingRedefined  ProtectionDomain protectionDomain  byte   classfileBuffer  throws IllegalClassFormatException                    String pd    null    protectionDomain     null    protectionDomain getCodeSource   toString                    out println className     loaded by     loader     at     new java util Date       in     pd                       dump stack trace of the thread loading class                  Thread dumpStack                        we just want the original  class bytes to be loaded                     we are not instrumenting it                    return null

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If your project is in a package like com blahcode and your class is called Main  the compiled files may be output in a directory structure like   out com blahcode Main class  This is especially true for IntelliJ IDEA   When trying to run from a shell or cmd  you need to cd to that which contains com as a sub-directory   cd out java -classpath   com blahcode Main

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I got this error after a Git branch change  For the specific case of Eclipse there were missed lines on  settings directory for org eclipse wst common component file  As you can see below Restoring the project dependencies with Maven Install would help

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I d like to correct the perspective of others on NoClassDefFoundError   NoClassDefFoundError can occur for multiple reasons like   ClassNotFoundException --  class not found for that referenced class irrespective of whether it is available at compile time or not i e base child class   Class file located  but Exception raised while initializing static variables Class file located  Exception raised while initializing static blocks    In the original question  it was the first case which can be corrected by setting CLASSPATH to the referenced classes jar file or to its package folder    What it means by saying  available in compile time      The referenced class is used in the code     Eg  Two classes  A and B extends A   If B is referenced directly in the code  it is available at compile time  i e  A a   new B      What it means by saying  not available at compile time     The compile time class and runtime class are different  i e  for example base class is loaded using classname of child class for example Class forName  classname   Eg  Two classes  A and B extends A   Code has A a   Class forName  B   newInstance

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Check that if you have a static handler in your class  If so  please be careful  cause static handler only could be initiated in thread which has a looper  the crash could be triggered in this way   1 firstly  create the instance of class in a simple thread and catch the crash   2 then call the field method of Class in main thread  you will get the NoClassDefFoundError   here is the test code   public class MyClass         private static  Handler mHandler   new Handler           public static int num   0      in your onCrete method of Main activity  add test code part    Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout activity main         test code start     new Thread new Runnable              Override         public void run                 try                   MyClass myClass   new MyClass                  catch  Throwable e                    e printStackTrace                                   start         try           Thread sleep 1000         catch  InterruptedException e            e printStackTrace              MyClass num   3         end of test code     there is a simple way to fix it using a handlerThread to init handler     private static Handler mHandler  private static HandlerThread handlerThread   new HandlerThread  newthread    static       handlerThread start        mHandler   new Handler handlerThread getLooper    mHandlerCB

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If you are using more than one module  you should have   dexOptions       preDexLibraries   false     in your build file

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if you are using gradlew  go to   gradle wrapper gradle-wrapper properties and change distributionUrl to the correct version of gradle  If you are using JDK14 try distributionUrl https    services gradle org distributions gradle-6 3-bin zip

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It happened to me in Android Studio   The solution that worked for me  just restart the studio

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One source of error for this exception could stem from inconsistent definitions for Proguard  e g  a missing  -libraryJars  path to a missing jar library     This explains why compilation and running works fine  given that the jar is there  while clean  amp  build fails  Remember to define newly added jar libraries in proguard setup   Note that error messages from Proguard are really not up to standard  as they are easily confused with similar ant messages arriving when the jar is not there at all  Only at the very bottom will there be a small hint of proguard in trouble  Hence  it is quite logic to start searching for traditional classpath errors etc  but this will be in vain   Evidently  the NoClassDefFound exception will be the results when running e g  the resulting executable jar built and based on a lack of proguard consistency  Some call it proguard  Hell

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I use the FileSync plugin for Eclipse so I can live debug on Tomcat  amp  I received NoClassFoundError because I had added a sync entry for the bin directory in the Eclipse workspace   gt  classes in the metadata for Tomcat but hadn t also added a folder sync for the extlib directory in Eclipse   gt   C  Users Stuart eclipse-workspace  metadata  plugins org eclipse wst server core tmp0 webapps myApp WEB-INF lib

[java] How to solve java.lang.NoClassDefFoundError?

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