package com.nigorojr.typebest;

public class Line {

}

@@ -29,27 +29,156 @@
 t;%0A%0A
-public class Line %7B%0A
+import java.util.ArrayList;%0A%0Aimport javax.swing.JPanel;%0A%0Apublic class Line extends JPanel %7B%0A    private ArrayList%3CWord%3E line = new ArrayList%3CWord%3E();
 %0A%7D%0A

Add inheritance from JPanel to Line class