# java.lang.NoClassDefFoundError

**URL:** <https://forum.cloverdx.com/t/java-lang-noclassdeffounderror/1578>\
**Category:** CloverDX Platform\
**Created:** [February 9, 2015, 12:00am UTC](https://forum.cloverdx.com/t/java-lang-noclassdeffounderror/1578 "2015-02-09T00:00:00Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![vladimir](https://avatars.discourse-cdn.com/v4/letter/v/94ad74/32.png) [@vladimir](https://forum.cloverdx.com/u/vladimir)\
**Post date:** [February 9, 2015, 12:00am UTC](https://forum.cloverdx.com/t/java-lang-noclassdeffounderror/1578/1 "2015-02-09T00:00:00Z")

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When I try to execute any graph in my server project, I have an error:

…  
Refresh interval: 5 (seconds)  
Wait for JMX client: true  
Connecting to CloverETL Server …  
Registering MBean with name: org.jetel.graph.runtime:type=CLOVERJMX\_1419590654107\_0  
Exception in thread “main” java.lang.NoClassDefFoundError: com/cloveretl/gui/jmx/bean/CloverServerJMXMBean  
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 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 com.cloveretl.gui.server.runtime.CloverServerProxy.a(Unknown Source)  
at com.cloveretl.gui.server.runtime.CloverServerProxy.startHook(Unknown Source)  
at com.cloveretl.gui.server.runtime.BaseCloverServerProxy.run(Unknown Source)  
at com.cloveretl.gui.server.runtime.CloverServerProxy.main(Unknown Source)  
Caused by: java.lang.ClassNotFoundException: com.cloveretl.gui.jmx.bean.CloverServerJMXMBean  
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)  
… 28 more

I have CloverETL Designer 3.5.2 installed and CloverETL Server 3.5.0.  
If anybody have an idea how to fix it, let me know please.

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**Author:** ![imriskal](https://avatars.discourse-cdn.com/v4/letter/i/b38774/32.png) [@imriskal](https://forum.cloverdx.com/u/imriskal)\
**Post date:** [February 16, 2015, 1:21pm UTC](https://forum.cloverdx.com/t/java-lang-noclassdeffounderror/1578/2 "2015-02-16T13:21:31Z")

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As the step #1, upgrade your CloverETL Server to the version matching with Designer, please. Incompatible versions (even minor versions) often result into unpredictable errors.

If the problem persists, let me know.

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**Author:** ![bennetcole](https://avatars.discourse-cdn.com/v4/letter/b/6de8d8/32.png) [@bennetcole](https://forum.cloverdx.com/u/bennetcole)\
**Post date:** [September 4, 2019, 5:47am UTC](https://forum.cloverdx.com/t/java-lang-noclassdeffounderror/1578/3 "2019-09-04T05:47:12Z")

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java.lang.NoClassDefFoundError This exception indicates that the JVM looked in its internal class definition data structure for the definition of a class and did not find it. This is different than saying that it could not be loaded from the classpath. Usually this indicates that we previously attempted to load a class from the classpath, but it failed for some reason - now we’re trying to use the class again (and thus need to load it, since it failed last time), but we’re not even going to try to load it, because we failed loading it earlier (and reasonably suspect that we would fail again). The earlier failure could be a [ClassNotFoundException](http://net-informations.com/java/cjava/notfound.htm) or an ExceptionInInitializerError (indicating a failure in the static initialization block) or any number of other problems. The point is, a NoClassDefFoundError is not necessarily a classpath problem.