Make fields final
Remove self call on equals
Safe equality check
Removed unreachable code
Localized parameter
Removed pointless bit operations
Remove pointless arithmetic operations
Replaced .equals("") check with .isEmpty() for better performance
Use characters instead of one element string
Replaces "" concat with other types with String.valueOf for more performance
Remove redundant call to toString of StringBuilder in String concatination
Replace single element lists with singletonLists
Use StringJoiner instead re-implementing it
this access
Weaker type
Unused paramter
String valueOf instead "" +
Weaken type to collection
this access
Comparison of Enums with equals
Pre-compiled pattern