Word abstract -> interface

app/src/main/java/hatelace/Word.java

@@ -1,11 +1,11 @@
 package hatelace;
 
-public abstract class Word {
-    public abstract <T> T getValue();
-    public abstract Word add(Word other);
-    public abstract Word subtract(Word other);
-    public abstract Word multiply(Word other);
-    public abstract Word divide(Word other);
-    public abstract String toString();
-    public abstract boolean equals(Object other);
+public interface Word {
+    <T> T getValue();
+    Word add(Word other);
+    Word subtract(Word other);
+    Word multiply(Word other);
+    Word divide(Word other);
+    String toString();
+    boolean equals(Object other);
 }

app/src/main/java/hatelace/memtypes/IntWord.java

@@ -2,7 +2,7 @@ package hatelace.memtypes;
 
 import hatelace.Word;
 
-public class IntWord extends Word {
+public class IntWord implements Word {
     private Integer value;
 
     public IntWord(Integer value) {

app/src/main/java/hatelace/memtypes/LongWord.java

@@ -2,7 +2,7 @@ package hatelace.memtypes;
 
 import hatelace.Word;
 
-public class LongWord extends Word {
+public class LongWord implements Word {
     private Long value;
 
     public LongWord(Long value) {