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
30
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
1
Number Theory
1
Object-oriented Programming
2
Parsing
2
Puzzles
6
Regular Expressions
85
Security
2
Strings
51
FEATURED TAGS
Cryptography
Data Science
Debugging
Games
Tutorials
85 Kata Found
6 kyu
Valid Phone Number
20,672
xDranik
2 Issues Reported
Regular Expressions
Algorithms
6 kyu
Split Strings
166,923
jhoffner
Regular Expressions
Strings
Algorithms
6 kyu
FIRE and FURY
1,313
dinglemouse
1 Issue Reported
Regular Expressions
Strings
Algorithms
1 kyu
Full Metal Chemist #2: parse me...
129
Blind4Basics
1 Issue Reported
Regular Expressions
Puzzles
Beta
Spanish DNI Validation Algorithm
25
adnan.ha
Status:
Testing & feedback needed
Estimated Rank:
6 kyu
Algorithms
Regular Expressions
5 kyu
Alphabet wars - nuclear strike
1,734
dcieslak
Strings
Regular Expressions
Fundamentals
6 kyu
DevOps legacy roasting -> disco inferno -> burn baby burn
292
user8476848
2 Issues Reported
Regular Expressions
Strings
Fundamentals
7 kyu
80's Kids #5: You Can't Do That on Television
1,689
NateBrady23
1 Issue Reported
Fundamentals
Algorithms
Strings
Regular Expressions
7 kyu
regex validation of 24 hours time.
1,892
daymos
5 Issues Reported
Regular Expressions
Date Time
Fundamentals
6 kyu
regex pattern to check if string has all characters
910
albertogcmr
1 Issue Reported
Regular Expressions
Fundamentals
Strings
7 kyu
Regexp basics - parsing prices
1,735
taw
Regular Expressions
Fundamentals
7 kyu
Regexp Basics - is it a vowel?
9,621
taw
2 Issues Reported
Regular Expressions
Fundamentals
7 kyu
Regexp Basics - is it a six bit unsigned number?
1,470
taw
Regular Expressions
Fundamentals
7 kyu
Regexp Basics - is it a letter?
8,525
taw
2 Issues Reported
Regular Expressions
Fundamentals
7 kyu
Regexp Basics - is it a hexadecimal number?
1,181
taw
3 Issues Reported
Regular Expressions
Fundamentals
7 kyu
Regexp Basics - is it a eight bit unsigned number?
1,581
taw
2 Issues Reported
Regular Expressions
Fundamentals
7 kyu
Regexp Basics - is it a eight bit signed number?
1,010
taw
3 Issues Reported
Bits
Binary
Strings
Regular Expressions
Fundamentals
8 kyu
Regexp Basics - is it a digit?
18,156
taw
6 Issues Reported
Regular Expressions
Fundamentals
7 kyu
Nickname Generator
12,768
cboha
1 Issue Reported
Strings
Regular Expressions
Fundamentals
5 kyu
Regex Password Validation
29,845
EricFreeman
2 Issues Reported
Regular Expressions
Fundamentals
5 kyu
Not very secure
49,633
mayrsascha
11 Issues Reported
Regular Expressions
Strings
8 kyu
String cleaning
28,003
mkelty
Regular Expressions
Fundamentals
Strings
7 kyu
The old switcheroo
9,282
joh_pot
1 Issue Reported
Strings
Regular Expressions
Fundamentals
5 kyu
String incrementer
51,699
parceval
6 Issues Reported
Regular Expressions
Strings
6 kyu
Convert string to camel case
203,683
jhoffner
20 Issues Reported
Regular Expressions
Algorithms
Strings
7 kyu
Remove anchor from URL
48,598
jhoffner
2 Issues Reported
Regular Expressions
Strings
Fundamentals
7 kyu
Remove consecutive duplicate words
7,751
e.mihaylin
Strings
Regular Expressions
Algorithms
7 kyu
Password maker
6,186
ChavXO
1 Issue Reported
Strings
Regular Expressions
Fundamentals
7 kyu
Where's Wally
1,137
JMurphyWeb
Regular Expressions
Fundamentals
6 kyu
Trumpness detector
1,140
GiacomoSorbi
3 Issues Reported
Regular Expressions
Strings
Algorithms
Loading...
Confirm
Collect:
undefined
Loading collection data...