I coded all of the problems besides DEMOPOEMS. which I keep getting an error. please help on the last part

Create a class named Poem that contains fields for the name of the poem and the number of lines in it. Include a constructor that requires values for both fields. Also include get methods to retrieve field values. Create three subclasses: Couplet, Limerick, and Haiku. The constructor for each subclass requires only a title; the lines field is set using a constant value. A couplet has two lines, a limerick has five lines, and a haiku has three lines. Create an application that demonstrates usage of an object of each type. Save the files as Poem.java, Couplet.java, Limerick.java, Haiku.java, and DemoPoems.java.