NoClassDefFoundError when calling Java from RPG

Hello;

(1) RPG code:

H DftActGrp(*NO) ActGrp(*CALLER)
D addStuff        PR            10i 0 ExtProc(*JAVA:
D                                       'MyClass':
D                                       'addStuff')
D                                     Static
D FirstInt                      10i 0 Value
D SecondInt                     10i 0 Value

D first           S             10i 0 Inz(23)
D second          S             10i 0 Inz(18)
D sum             S             10i 0
/Free
        sum = addStuff(first:second);
        Dsply sum;
         *InLr = *On;
/End-Free

(2) Java code:
public class MyClass {
   public static int addStuff(int first, int second) {
       return first + second;
   }

   public static void main(String[] args) {
      System.out.println("start...");
      System.out.println(addStuff(11, 22));
   }
}

(3) Set CLASSPATH by using
==> ADDENVVAR ENVVAR(CLASSPATH) VALUE('/home')

(4) Run MyClass by using
==> JAVA CLASS(MyClass)
It worked! This showed that CLASSPATH was set correctly.

(5) Run RPG program and I got this error:

Java exception received when calling Java method (C G D F)
Cause . . . . . :   RPG procedure CALLJAVA3 in program PRODLIB/CALLJAVA3
  received Java exception "java.lang.NoClassDefFoundError: MyClass" when
  calling method "addStuff" with signature "(II)I" in class "MyClass".

Help!

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