I am working on moving code from R2007a to R2013a. I am getting a java.lang.NoClassDefFoundError during my run in R2013a which does not appear in R2007a. It occurs when I call.
feval('get',fname,jevent);
Where fname is a product.ProxyField object for an Object Filter and jevent is a product.format.java.internal.JavaEvent.
The class is in a jar file on the path and is being accessed by another class in the same jar file. The stack trace does not leave the realm of the product if that helps.
I do not have access to the original code for the jar file. I do have access to code derived from that original code and both classes are in the same package. I'm guessing this has something to do with differences in the java version but I'm not sure what to do since I don't have the original code to recompile.
Unfortunately I can't provide actual source or full detail but a google search only yielded results for MATLAB startup issues. Any thoughts?
Seems like the difference between R2007a and R2013a is that the first uses 1.5 jre and second uses 1.6 jre. It would be easier to help you if you provided the stack trace showing the exception. Sometimes classes get moved around in between jvm versions, so having the actual missing classes would help in determining if the missing class is a class that was just moved around to a different package. You could take the missing class, google it adding the same exception message as you put above and seeing who else ran into similar issues.
Related
I've been on a project where I build tetris that has multiplayer, and it's been working for a couple of days with no problem, but now suddenly there's this exception:
Exception in thread "main" java.lang.NoClassDefFoundError: Game/Piece
This basically means it can't find the .class of my class called Piece, but whenever I do a "clean and build" the .class file appears, then instantly disappears when I run the project.
This is my project structure (running with JDK 16, in netbeans):
Is there a reason for this exception?
My JAVA_HOME variable: jdk1.8.0_131.
While it's possible that this is due to a classpath mismatch between compile-time and run-time, it's not necessarily true.
It is important to keep two or three different exceptions straight in our head in this case:
java.lang.ClassNotFoundException This exception indicates that the class was not found on the classpath. This indicates that we were trying to load the class definition, and the class did not exist on the classpath.
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 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.
And this question has been asked before.
This type of error can appear for multiple reasons :
Because the compiler is too different than the JVM, specially with new Java syntax.
Personally, I had this type of error by running Java 16 code with Java 8 JRE, and I fix it by removing the package with the Java 16 code.
Because you were using deprecated class, which have been removed since this date.
So, to fix your issue, there is multiple ways:
Use same Java in Netbeans and in your project config (to prevent change)
Upgrade your Java JRE installed (instead of old Java 8 version) to have both Java 16
Downgrade Netbeans JDK to Java 8 to have both Java 8
The objective is to use the same JVM than JDK, to see all warns/error that are linked to your current code.
So apperantly I had a warning (not an error) when compiling, it said something was depracated, so I had to add a compiler option name -Xlint:(something here I can't remember), so when I compiled it the issue was obvious, JFrame.hide() is a depracated function so I just had to remove it. It's weird that the runtime error was "NoClassDefFoundError" which has nothing to do with the issue.
I am trying to compile a java file, which uses package com.sun.xml.internal.messaging.saaj.soap.dynamic, using ANT-1.9.3 but I'm receiving error
package com.sun.xml.internal.messaging.saaj.soap.dynamic does not
exist
I tried compiling both JDK7 and JDK 8 and getting the same error.
I can see the package exist inside rt.jar of both JDK. I have set JAVA_HOME also properly.
Can someone help me to resolve this issue?
Unfortunately for you, this behaviour is probably intentional and your usage is deliberately unsupported. If your code used to compile under Java6 and now doesn't under Java7 or Java8 then you've basically fallen foul of
From one release to another, these classes may be removed, or they may be moved from one package to another
http://www.oracle.com/technetwork/java/faq-sun-packages-142232.html
See also http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6778491 for a technical description of a possible cause of not being able to compile a class which references a 'com.sun.*' class but which throws the same compiler error you're seeing despite the fact that the referenced class exists in rt.jar. Also for the kind of response which Oracle give to bug reports relating to it;)
Unfortunately, using undocumented, unsupported APIs often has this kind of 'bite you in the posterior' kind of effect.
Please add the line, < compilerarg line="-XDignore.symbol.file" compiler="modern"/ > for < javac > tag in your build.xml. This should solve your problem. It solved for me.
For reference you can view the forum link
http://www.icesoft.org/JForum/posts/list/19871.page#sthash.srrN9Ijk.dpbs
I'm looking to store Java libraries inside my Oracle database. Note that this is the first time I'm doing that. That library is pd4ml. It is made up of two jars, which contains the compiled classes.
pd4ml.jar
ss_css2.jar (required by pd4ml.jar)
As loading them with Toad did not work (Toad said they were loaded successfully, but did they not show up anywhere) I went command line (loadjava) and managed to load ss_css2.jar successfully. All its classes were loaded and compiled.
The second library, pd4ml.jar, was also loaded, but several classes won't compile. I ran ojvmtc to try to resolve references. I got the following message:
The following classes could not be found:
javax/servlet/http/HttpServletResponseWrapper
org/zefer/pd4ml/npdf/parser/c
The first one, if my understanding is correct, should be part of the JRE that is built-in 11g r2. Browsing the sys schema, it does not appear to exist.
The second one is part of the jar library. Now I'm not exactly sure of the structure of compiled Java, I've never had to look into it before, but I have several .class files inside org/zefer/pd4ml/npdf/parser/, these being: c$_b, c$_c.... to c$_g. There is none that is only c.
The library works well on my local machine when passing command line arguments or running it from Eclipse, so it should work. There is no specific error message that shows up when trying to compile them in Toad. I have a feeling it's a dependencies/classpath issue.
Any hints on how I should ensure that classes contained in pd4ml.jar can properly access those in ss_css2.jar , or any potential causes to investigate? Perhaps a way to get detailed error messages from the Java code?
The strange class names like c$_b, c$_c.... to c$_g are result of JAR file obfuscation. The obfuscation impacts only non-public classes, so it should not harm.
As I see, in your particular case javax/servlet/http/HttpServletResponseWrapper class is missing (and probably few more) - the classes can be found in servlet-api.jar. Just take the file from any J2EE (or Tomcat) distribution and add the file to your project/application.
In usual scenarios the servlet-api classes are required only when WebApp-specific PD4ML methods are called. And the methods are called only when pd4ml.jar is a part of a web application (that means servlet-api.jar is among the application resources).
As I see now, Oracle database Java sub-system scans for all referenced resources (even if they are not needed in a scenario) and panic if anything is missing.
I am trying hard to find the cause of a weird JSF error. To do this, I try to debug the source code inside javaee-web-api module where a NullPointerException is thrown during JSF rendering. But I am stuck because the debugger does not show me the source code of that location.
There is a discussion thread that says that javaee-web-api is stripped (no bytecode for methods) and meant to be used only for compilation.
What does this mean? Can someone explain it in more detail? I want to understand why I cannot debug the location where that NullPointerException is thrown. I think this is related to the fact that these JARs are stripped.
Normally, the class files in a jar file will contain information on the line numbers relating to the code in the class - this is called the debug information. A stripped jar simply does not have this information.
You are correct in assuming this is the problem. The stack trace you see won't contain any line numbers relating to the code in the stripped jar. Since the jar is provided by a third-party, there's nothing you can do to get that information.
I have a serializable class (CardGame) that I'm working with in Eclipse, and had originally put it in a package (x.cardlib). I renamed the package to y.cards.models using Eclipse's refactoring utility (now that I know how to properly name a package).
I wrote a new class (CardGameDatabase) that downloads and converts serialized CardGames from a database, and wrote a new JUnit test case (CardGameDatabaseTest) for it later on. I tried to run my test case, and received the following error:
java.lang.ClassNotFoundException: x.cardlib.CardGame
at y.cards.database.CardGameDatabase.getGame(CardGameDatabase.java:28)
at y.tests.CardGameDatabaseTest.test(CardGameDatabaseTest.java:13)
I figured that I must still have a reference to the old package in my code, so I did a project-wide search for any and all references to the old package (e.g. "import x.cardlib.CardGame"). I didn't find any.
I then deleted all compiled code and ran Eclipse's cleanup utility, thinking that maybe an old reference existed in previously compiled code. I'm still receiving the error.
(Hm, I figured it out while writing, in fact. I'll post the answer shortly in case anyone else has had a problem like this.)
Answer: I had stored the CardGame in my database before I refactored my code. Upon downloading the object from the database, it was still called x.cardlib.CardGame in the database. In short, renaming the package broke my serialization, leading to a ClassNotFoundException.