How To Solve Java.lang.noclassdeffounderror Error
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How To Resolve Noclassdeffounderror In Java
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Noclassdeffounderror: Could Not Initialize Class
vote 79 down vote favorite 22 I'm pretty new to Java, and I've just started learning about packages in Java. 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$1.run(URLClassLoader.java:355) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:354) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) noclassdeffounderror vs classnotfoundexception at sun.misc.Launcher$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? Any help would be appreciated. Thanks. UPDATE Thanks for the answers. They really helped. 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. Thanks a lot for the answers! java exception packages noclassdeffounder
java.lang.NoClassDefFoundError: How to resolve - Part 1 6/08/2012 Pierre-Hugues Charbonneau 48 comments Exception in thread "main" java.lang.NoClassDefFoundError is one of the most common and difficult problems that you can face when developing Java EE enterprise noclassdeffounderror android studio or standalone Java applications. The complexity of the root cause analysis and resolution process will java.lang.noclassdeffounderror wrong name depend of the size of your Java EE middleware environment, especially given the high number of class loaders present across the various Java how to fix noclassdeffounderror EE applications. What I'm proposing to you is a series of articles which will provide you with a step by step approach on how to troubleshoot and resolve such problem. I will also share the most common http://stackoverflow.com/questions/17973970/how-to-solve-java-lang-noclassdeffounderror Java NoClassDefFoundError problem patterns I have observed over the last 10 years. Sample Java programs will also be available in order to simplify your learning process. I also encourage you to post comments, share your problem case and ask me any question on this subject. The part 1 of the series will focus on a high level overview of this Java runtime error along with a Java ClassLoader overview. java.lang.NoClassDefFoundError - what is it? http://javaeesupportpatterns.blogspot.com/2012/06/javalangnoclassdeffounderror-how-to.html ** Tutorial video is now available:http://www.youtube.com/watch?v=Nn_Pq8cWiBg Now let's begin what a simple overview of this problem. This runtime error is thrown by the JVM when there is an attempt by a ClassLoader to load the definition of a Class (Class referenced in your application code etc.) and when such Class definition could not be found within the current ClassLoader tree. Basically, this means that such Class definition was found at compiled time but is not found at runtime. Simple enough, what about adding the missing Class to the classpath? Well not so fast, this type of problem is not that simple to fix. Adding the missing Class / JAR to your runtime application classpath / ClassLoader is just one of the many possible solutions. The key is to perform proper root cause analysis first. This is exactly why I'm creating this whole series. For now, just keep in mind that this error does not necessarily mean that you are missing this Class definition from your "expected" classpath or ClassLoder so please do not assume anything at this point. Java ClassLoader overview Before going any further, it is very important that you have a high level of understanding of the Java ClassLoader principles. Quite often individuals debugging NoClassDefFoundError problems are struggling because they are lacking proper knowledge and understanding of Java ClassLoader principle
Tomcat Unix Tuesday, 6 March 2012 6 ways to resolve java.lang.NoClassDefFoundError in java How to fix for java.lang.NoClassDefFoundError error in java NoClassDefFoundError in java is one of the strange error used to get in java applications. Usually when we run java programs, we http://www.cloudhadoop.com/2012/03/6-ways-to-resolve-javalangnoclassdeffou.html used to get the Exception in thread "main" java.lang.NoClassDefFoundError: in our programs I got this exception alot of times. Solving this NoClassDefFoundError is very easy but we have to know the ways to solve this.NoClassDefFoundError exception will be in different cases like windows,linux,unix and tomcat/websphere,jboss. I am going to explains about the sample program assumes that which throwsNoClassDefFoundError and fix for this error. public class HelloWorldDemo { how to public static void main(String args[]) { System.out.println("Hello world test message"); } } This is sample hello world program,When i compile this program using javac HelloWorld.java command, this compiles fine and generates HelloWorld.class in the current directory, After running this programm using java HelloWorld command, I am getting the below exceptions. Exception in thread "main" java.lang.NoClassFoundError: HelloWorld thread main throws this error and exit the program abnormally. This reason error in java for this error is java virtual machine can not find class file at run time. java command looks for the classes that are there in the current directory, so if your class file is not in current directory, you have to set in classpath, so the solution is to place this .class file in the classpath classpath is the enviornment variable in every system which points to class files in the directories. if you classfile is in jar file, jar should be in classpath. classpath can be absolute(complete path) or relative path( related to directory ) Many ways to solve java.lang.NoClassDefFoundError exception. Following are the different cases where this error is occured and fix for them. 1. solve java.lang.NoClassDefFoundError :- HelloWorld.class is not avialble at runtime, so we have to set the class file to java command using -classpath option java -classpath . HelloWorld This is for fixing NoClassDefFoundError error by setting classpath inline for java command. We are instructing the jvm to look for the HelloWorld.class in the current directory by specifying . if class file is in different directory, we need specify the complete directory absolute or relative path instead of . for java command 2. Fix for java.lang