If these are counting numbers and the particular bit values don't matter much, why not make them:

```java
TO_NEIGHBOR((byte) (2 << 4)),
REPLACE_NODE((byte) (3 << 4)),
KILL_SELF((byte) (4 << 4)),
FROM_DEAD((byte) (5 << 4));
ADD_READIDS((byte) (7 << 4));
```

Also, is there a reason 6 is missing?