Kata Library: Java Practice
Sign Up
Time to claim your honor
Training
Practice
Complete challenging
Kata
to earn honor and ranks. Re-train to hone technique
Freestyle Sparring
Take turns remixing and refactoring others code through
Kumite
Community
Leaderboards
Achieve honor and move up the global leaderboards
Chat
Join our
Discord
server and chat with your fellow code warriors
Discussions
View our
Github Discussions
board to discuss general Codewars topics
About
Docs
Learn about all of the different aspects of Codewars
Blog
Read the latest news from Codewars and the community
Log In
Sign Up
Library
Collections
Newest
Oldest
Popularity
Positive Feedback
Most Completed
Least Completed
Hardest
Easiest
Name
Relevance
Low Satisfaction
All
My Languages
Agda (Beta)
BF (Beta)
C
CFML (Beta)
Clojure
COBOL (Beta)
CoffeeScript
CommonLisp (Beta)
Coq
C++
Crystal
C#
D (Beta)
Dart
Elixir
Elm (Beta)
Erlang (Beta)
Factor (Beta)
Forth (Beta)
Fortran (Beta)
F#
Go
Groovy
Haskell
Haxe (Beta)
Idris (Beta)
Java
JavaScript
Julia (Beta)
Kotlin
λ Calculus (Beta)
Lean
Lua
NASM
Nim (Beta)
Objective-C (Beta)
OCaml (Beta)
Pascal (Beta)
Perl (Beta)
PHP
PowerShell (Beta)
Prolog (Beta)
PureScript (Beta)
Python
R (Beta)
Racket
Raku (Beta)
Reason (Beta)
RISC-V (Beta)
Ruby
Rust
Scala
Shell
Solidity (Beta)
SQL
Swift
TypeScript
VB (Beta)
Approved & Beta
Approved
Beta
All
Kata I have not trained on
Kata I have not completed
Kata I have completed
8 kyu
easiest
7 kyu
6 kyu
5 kyu
4 kyu
3 kyu
2 kyu
1 kyu
hardest
Algorithms
31
Arrays
7
Binary
2
Bits
1
Ciphers
2
Cryptography
1
Data Structures
1
Date Time
1
Debugging
1
Esoteric Languages
1
Filtering
1
Fundamentals
51
Games
4
Interpreters
1
Logic
2
Number Theory
1
Object-oriented Programming
2
Parsing
2
Puzzles
6
Regular Expressions
86
Security
2
Strings
51
FEATURED TAGS
Cryptography
Data Science
Debugging
Games
Tutorials
86 Kata Found
4 kyu
Breadcrumb Generator
4,737
GiacomoSorbi
1 Issue Reported
Parsing
Regular Expressions
Algorithms
7 kyu
Check whether a number is valid in a given numeral system
904
SummerTheCoder
Algorithms
Logic
Regular Expressions
1 kyu
Full Metal Chemist #2: parse me...
131
Blind4Basics
1 Issue Reported
Regular Expressions
Puzzles
6 kyu
Valid Phone Number
21,151
xDranik
2 Issues Reported
Regular Expressions
Algorithms
6 kyu
Split Strings
167,342
jhoffner
Regular Expressions
Strings
Algorithms
6 kyu
FIRE and FURY
1,327
dinglemouse
1 Issue Reported
Regular Expressions
Strings
Algorithms
Beta
Spanish DNI Validation Algorithm
27
adnan.ha
Status:
Testing & feedback needed
Estimated Rank:
6 kyu
Algorithms
Regular Expressions
5 kyu
Alphabet wars - nuclear strike
1,743
dcieslak
Strings
Regular Expressions
Fundamentals
6 kyu
DevOps legacy roasting -> disco inferno -> burn baby burn
294
user8476848
2 Issues Reported
Regular Expressions
Strings
Fundamentals
7 kyu
80's Kids #5: You Can't Do That on Television
1,691
NateBrady23
1 Issue Reported
Fundamentals
Algorithms
Strings
Regular Expressions
7 kyu
regex validation of 24 hours time.
1,907
daymos
5 Issues Reported
Regular Expressions
Date Time
Fundamentals
6 kyu
regex pattern to check if string has all characters
917
albertogcmr
1 Issue Reported
Regular Expressions
Fundamentals
Strings
7 kyu
Regexp basics - parsing prices
1,740
taw
Regular Expressions
Fundamentals
7 kyu
Regexp Basics - is it a vowel?
9,627
taw
2 Issues Reported
Regular Expressions
Fundamentals
7 kyu
Regexp Basics - is it a six bit unsigned number?
1,471
taw
Regular Expressions
Fundamentals
7 kyu
Regexp Basics - is it a letter?
8,529
taw
2 Issues Reported
Regular Expressions
Fundamentals
7 kyu
Regexp Basics - is it a hexadecimal number?
1,182
taw
3 Issues Reported
Regular Expressions
Fundamentals
7 kyu
Regexp Basics - is it a eight bit unsigned number?
1,583
taw
2 Issues Reported
Regular Expressions
Fundamentals
7 kyu
Regexp Basics - is it a eight bit signed number?
1,011
taw
3 Issues Reported
Bits
Binary
Strings
Regular Expressions
Fundamentals
8 kyu
Regexp Basics - is it a digit?
18,202
taw
6 Issues Reported
Regular Expressions
Fundamentals
7 kyu
Nickname Generator
12,787
cboha
1 Issue Reported
Strings
Regular Expressions
Fundamentals
5 kyu
Regex Password Validation
29,925
EricFreeman
2 Issues Reported
Regular Expressions
Fundamentals
5 kyu
Not very secure
49,779
mayrsascha
11 Issues Reported
Regular Expressions
Strings
8 kyu
String cleaning
28,075
mkelty
Regular Expressions
Fundamentals
Strings
7 kyu
The old switcheroo
9,334
joh_pot
1 Issue Reported
Strings
Regular Expressions
Fundamentals
5 kyu
String incrementer
51,811
parceval
6 Issues Reported
Regular Expressions
Strings
6 kyu
Convert string to camel case
204,160
jhoffner
20 Issues Reported
Regular Expressions
Algorithms
Strings
7 kyu
Remove anchor from URL
48,716
jhoffner
2 Issues Reported
Regular Expressions
Strings
Fundamentals
7 kyu
Remove consecutive duplicate words
7,769
e.mihaylin
Strings
Regular Expressions
Algorithms
7 kyu
Password maker
6,197
ChavXO
1 Issue Reported
Strings
Regular Expressions
Fundamentals
Loading...
Confirm
Collect:
undefined
Loading collection data...