I tried

src/com/imegumii/NDFA.java

@@ -0,0 +1,16 @@
+package com.imegumii;
+
+import java.util.SortedSet;
+
+/**
+ * Created by imegumii on 01/05/2017.
+ */
+public class NDFA<T extends Comparable> extends Automata<T> {
+    public NDFA(Character[] symbols) {
+        super(symbols);
+    }
+
+    public NDFA(SortedSet<Character> symbols) {
+        super(symbols);
+    }
+}