#fixed code
                                @Override
    public Essence run(Particle particle) {
        while (factors[0].getValue(PBoolean.class).isTrue()) {
            Essence o = super.run(particle);
            if (o != null) {
                return o;
            }
        }
        return null;
    }
#vulnerable code 
                                @Override
    public Essence run(Particle particle) {
        while (parameters[0].getValue(PBoolean.class).isTrue()) {
            Essence o = super.run(particle);
            if (o != null) {
                return o;
            }
        }
        return null;
    } 
                            #location 3 
                            #vulnerability type NULL_DEREFERENCE