@Override
    protected VariableMapping clone() throws CloneNotSupportedException {
        VariableMapping clone = (VariableMapping) super.clone();
        clone.leftVariable = leftVariable.clone();
        if (rightVariable != null) {
            clone.rightVariable = rightVariable.clone();
        }
        return clone;
    }
jme serialization (not used)

@param im the importer
@throws IOException from the importer
jme3-core/src/main/java/com/jme3/shader/VariableMapping.java