NoClassDefFoundError while trying to run my jar with java.exe -jar...what's wrong?

The -jar option is mutually exclusive of -classpath. See an old description here

-jar

Execute a program encapsulated in a JAR file. The first argument is the name of a JAR file instead of a startup class name. In order for this option to work, the manifest of the JAR file must contain a line of the form Main-Class: classname. Here, classname identifies the class having the public static void main(String[] args) method that serves as your application's starting point.

See the Jar tool reference page and the Jar trail of the Java Tutorial for information about working with Jar files and Jar-file manifests.

When you use this option, the JAR file is the source of all user classes, and other user class path settings are ignored.

A quick and dirty hack is to append your classpath to the bootstrap classpath:

-Xbootclasspath/a:path

Specify a colon-separated path of directires, JAR archives, and ZIP archives to append to the default bootstrap class path.

However, as @Dan rightly says, the correct solution is to ensure your JARs Manifest contains the classpath for all JARs it will need.

You can omit the -jar option and start the jar file like this:

java -cp MyJar.jar;C:\externalJars\* mainpackage.MyMainClass

This is the problem that is occurring,

if the JAR file was loaded from "C:\java\apps\appli.jar", and your manifest file has the Class-Path: reference "lib/other.jar", the class loader will look in "C:\java\apps\lib\" for "other.jar". It won't look at the JAR file entry "lib/other.jar".

Solution:-

1. Right click on project, Select Export.
2. Select Java Folder and in it select Runnable JAR File instead of JAR file.
3. Select the proper options and in the Library Handling section select the 3rd option i.e. (Copy required libraries into a sub-folder next to the generated JAR).

[ EDIT = 3rd option generates a folder in addition to the jar, 2nd option ("Package required libraries into generated JAR") can also be used as you have the jar. ]

4. Click finish and your JAR is created at the specified position along with a folder that contains the JARS mentioned in the manifest file.

5. open the terminal,give the proper path to your jar and run it using this command java -jar abc.jar

   Now what will happen is the class loader will look in the correct folder for the referenced JARS since now they are present in the same folder that contains your app JAR..There is no "java.lang.NoClassDefFoundError" exception thrown now.

This worked for me... Hope it works for you too!!!