Re: generic constructor call with concret type

    @SuppressWarnings("unchecked")
    public Run(Class<? extends T> cl) {
    if (cl == Float.class) {
        helper = (Inner<T>) new DoFloat();
    } else if (cl == Double.class) {
        helper = (Inner<T>) new DoDouble();
    } else {
        throw new IllegalArgumentException("Invalid type: " + cl);
    }
    }

    @Override
    public T doSomething() {
    return helper.doAnother();
    }

    // Test
    public static void main(String[] args) {
    final Base<Double> rd = new Run<Double>(Double.class);
    final Base<Float> rf = new Run<Float>(Float.class);
    System.out.println("Double: " + rd.doSomething());
    System.out.println("Float: " + rf.doSomething());

    final Base<Integer> ri = new Run<Integer>(Integer.class);
    System.out.println("Integer: " + ri.doSomething());

    // final Base<Integer> wontCompile = new Run<Integer>(Double.class);
    }
}

Btw, what do you need that for?