import java.lang.reflect.*;
import java.util.Arrays;

class Test {
    class Inner {
        public <T> Inner(T arg) {}
    }

    public static void main(String[] args) {
        Constructor<?> constructor = Test.Inner.class.getConstructors( )[0];
        System.out.println(
            "Regular parameters: " +
            Arrays.toString(constructor.getParameterTypes()) +
            "nGeneric parameters: " +
            Arrays.toString(constructor.getGenericParameterTypes())
        );
    }
}

Test.Inner foo = new Test().new Inner(new Object());