ClassNotFoundException

[Daniel Smith]

I'm just trying to get a Hello World plugin working but I cannot figure out the cause of this error because I do not know much about Java.

Plugin:   http://tysmith.net/HelloWorld_Sc2Gears.zip

Error:   

Failed to start plugin "HelloWorld_Sc2Gears"!

java.lang.ClassNotFoundException: net.tysmith.HelloWorld_Sc2Gears

at java.net.URLClassLoader$1.run(Unknown Source)

at java.net.URLClassLoader$1.run(Unknown Source)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at hu.belicza.andras.sc2gears.services.plugins.PluginControl.startPlugin(PluginControl.java:140)

at hu.belicza.andras.sc2gears.services.plugins.PluginManager.startEnabledPlugins(PluginManager.java:168)

at hu.belicza.andras.sc2gears.ui.MainFrame.<init>(MainFrame.java:366)

at hu.belicza.andras.sc2gears.Sc2gears.main(Sc2gears.java:129)

[András Belicza]

Hi,

The problem is with the plugin.jar.

First you have to compile the Java file. use the "javac" command for this.

You have to place the .java file to a folder matching the package declaration. For example if your package is "net.tysmith", it has to be in a package of "net/tysmith". The package must not contain the class name, so remove that from the package declaration.

If the javac command succeeds, you will have a ".class" file. That has to be packaged in the jar file. You can use the "jar" command to make the jar file.

Today's IDE software can do all this for you. I recommend Eclipse.

[Daniel Smith]

Hello,

Thanks for the fast response.  I am using eclipse.  Here is my eclipse workspace folder: http://tysmith.net/tmp/HelloWorld_Sc2Gears.zip

I have eclipse set to build automatically.  

I have done the following things with no results:

1. Use eclipse to export a JAR file

2. >jar cf HelloWorld_Sc2Gears.jar HelloWorld_Sc2Gears.class

The class file I JAR'd was in workspace/bin/net/tysmith/HelloWorld_Sc2Gears/HelloWorld_Sc2Gears.class

Is there some option I need to make sure I set with eclipise?

Thank you,

Ty

[András Belicza]

The problem is the class file folder.

To make it clear: if you have a java class which has a package declaration of "net.tysmith.HelloWorld_Sc2Gears" the class file has to be in a folder of "net/tysmith/HelloWorld_Sc2Gears".

When it is exported to a jar file (the jar file is a normal zip file), the class has to be placed in the same folder.

So the jar has to contain 2 files:

/net/tysmith/HelloWorld_Sc2Gears/HelloWorld_Sc2Gears.class

/META-INF/MANIFEST.MF

[András Belicza]

Also there is another error.

The Sc2gears-plugin.xml file must list the main class of the plugin.

The main class is the class name plus the full package name. In your case:

net.tysmith.HelloWorld_Sc2Gears.HelloWorld_Sc2gears

(In the example you sent the class name is missing from the end, you only entered the package name.)

[Daniel Smith]

You fixed it.  Thanks a lot.