javadoc doclet and static results in NoClassDefFoundError

import com.sun.javadoc.*;
import org.apache.log4j.Logger;

public class ListClass {
    public static final Logger log = Logger.getLogger("ListClass");

    public static boolean start(RootDoc root) {
        ClassDoc[] classes = root.classes();
        for (int i = 0; i < classes.length; ++i) {
             System.out.println(classes[i]);
        }
        return true;
    }
}

to compile: javac -cp tools.jar;log4j-1.2.17.jar ListClass.java

to run: javadoc -doclet ListClass -docletpath . -classpath log4j-1.2.17.jar;tools.jar ListClass.java

This will generate a NoClassDefFoundError. But if I remove the static keyword, it works fine. Any ideas how to make this work with the static keyword?

This made it work as suggested by my boss.

javadoc -doclet ListClass -docletpath .;log4j-1.2.17.jar -classpath log4j-1.2.17.jar;tools.jar ListClass.java