Java.lang.NoClassDefFoundError java.lang.StringBuilder from code using java.lang.StringBuffer

Question

Hi,

I know there are plenty of questions regarding this error, but I haven't found it easy to find one exactly like mine.

Here goes.

I have a pretty small application that writes DB data to a csv file and then uploads it to a server. I have it running on my local box out of eclipse which is great, but the final version needs to be run as a cron job on a server box from command line.

I'm working on the command line call for the main java class and its giving me lots of trouble.

My dependency structure is as such: My classes

• package=gtechReconcile
• classes= GtechReconciler.java, CSVFile.java, QueryMachine.java, FTPSender.java

My external libs

• ojdbc14.zip
• edtftpj.jar

I run the following line in the terminal in the directory above the compile source package (ie /path/to/classes where /path/to/classes/gtechReconcile/ has all the compiled class files) This path is the current directory when the command line is run :

java -cp /<snip>/lib/ojdbc14.zip:/<snip>/lib/edtftpj.jar:/path/to/classes gtechReconcile.GtechReconciler

The error then tells me it can't find java.lang.StringBuilder, even though this does not exist in my code. I use a StringBuffer, which apparently StringBuilder has replaced since Java5. Perhaps the java compiler converted this to StringBuilder, which the jvm then does not resolve?

What am I missing here?

EDIT : added error from prompt (clarified where this executes from and what is present in the package folder):

[gtechReconcile]$ pwd
/path/to/
[gtechReconcile]$ cd classes/gtechReconcile/
[gtechReconcile]$ ls
CSVFile.class  FTPSender.class  GtechReconciler.class  QueryMachine.class  reports
[gtechReconcile]$ cd ..
[classes]$ ls
gtechReconcile
[classes]$ java -cp .:/path/to/lib/ojdbc14.zip:/path/to/lib/edtftpj.jar gtechReconcile.GtechReconciler
Creating file
Exception in thread "main" java.lang.NoClassDefFoundError: while resolving class: gtechReconcile.CSVFile
at java.lang.VMClassLoader.resolveClass(java.lang.Class) (/usr/lib/libgcj.so.5.0.0)
at java.lang.Class.initializeClass() (/usr/lib/libgcj.so.5.0.0)
at gtechReconcile.GtechReconciler.main(java.lang.String[]) (Unknown Source)
Caused by: java.lang.ClassNotFoundException: java.lang.StringBuilder not found in [file:./, file:/opt/mms_tstt2/gtechReconcile/lib/ojdbc14.zip, file:/opt/mms_tstt2/gtechReconcile/lib/edtftpj.jar, file:/usr/share/java/libgcj-3.4.6.jar, file:./, core:/]
at java.net.URLClassLoader.findClass(java.lang.String) (/usr/lib/libgcj.so.5.0.0)
at gnu.gcj.runtime.VMClassLoader.findClass(java.lang.String) (/usr/lib/libgcj.so.5.0.0)
at java.lang.ClassLoader.loadClass(java.lang.String, boolean) (/usr/lib/libgcj.so.5.0.0)
at _Jv_FindClass(_Jv_Utf8Const, java.lang.ClassLoader) (/usr/lib/libgcj.so.5.0.0)
at java.lang.Class.forName(java.lang.String, boolean, java.lang.ClassLoader) (/usr/lib/libgcj.so.5.0.0)
at _Jv_BytecodeVerifier.verify_instructions_0() (/usr/lib/libgcj.so.5.0.0)
at _Jv_VerifyMethod(_Jv_InterpMethod) (/usr/lib/libgcj.so.5.0.0)
at _Jv_PrepareClass(java.lang.Class) (/usr/lib/libgcj.so.5.0.0)
at _Jv_WaitForState(java.lang.Class, int) (/usr/lib/libgcj.so.5.0.0)
at java.lang.VMClassLoader.linkClass0(java.lang.Class) (/usr/lib/libgcj.so.5.0.0)
at java.lang.VMClassLoader.resolveClass(java.lang.Class) (/usr/lib/libgcj.so.5.0.0)
...2 more

Answer 1

The default classpath (if you don't specify one) is the current directory (".").

However, if you specify a classpath, java will use that instead of the default, thus removing the current directory.

The solution to your problem is simple: add the "current directory" to your class path, such as:

java -cp .:/<snip>/lib/ojdbc14.zip:/<snip>/lib/edtftpj.jar:/<snip>/bin/ gtechReconcile.GtechReconciler

Answer 2

The exception is raised when you create a new StringBuilder in your CSVFile class. Google tells me it's a frequent problem with GCJ, use an official Sun JVM. It usally resolves this kind of problem.

---

The gtechReconcile folder is assumed to contains all the class files in the gtechReconcile package.

In example, if you have /path/to/classes/gtechReconcile/GtechReconciler.class, you have two options.

1. Go to /path/to/classes, add to the classpath the current directory (.) and run java as you did before.
2. Add /path/to/classes to the classpath and run java wherever you like.