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Java Track Management

This page provides the Exercism community with the information and tools needed to manage the Java track.

Students
283,188
Submissions
4,875,499
Mentoring Discussions
17,721

The Java track is healthy ✅

Building

Java syllabus

Learn More

Help create the track syllabus: is a set of concepts and learning exercises put together to teach foundational elements of the programming language.

Next goal: Create a complete syllabus with at least 30 concepts. Find out more.
26 concepts being taught
Ba
Basics
61,611 learnt
Bo
Booleans
35,697 learnt
Ar
Arrays
18,385 learnt
Fo
For Loops
18,385 learnt
Fo
For-Each Loops
18,385 learnt
Ge
Generic Types
13,297 learnt
Li
Lists
13,297 learnt
Ex
Exceptions
6,858 learnt
Ch
Chars
11,716 learnt
Cl
Classes
12,536 learnt
Co
Constructors
9,169 learnt
In
Interfaces
6,795 learnt
If
If-Else Statements
18,676 learnt
Nu
Numbers
18,676 learnt
St
Strings
23,593 learnt
Te
Ternary Operators
11,000 learnt
Sw
Switch Statements
7,944 learnt
In
Inheritance
7,157 learnt
En
Enums
4,276 learnt
Nu
Nullability
7,623 learnt
Ra
Randomness
4,965 learnt
Da
Date-Time
5,153 learnt
Me
Method Overloading
3,563 learnt
Bi
Bit Manipulation
4,567 learnt
Se
Sets
3,478 learnt
Ma
Maps
2,599 learnt
22 active learning exercises
Started
Attempts
Completions
Mentoring requests
Cook Your Lasagna Cook Your Lasagna
101,759
555,757 (avg. 5.5)
61,611 (60.5%)
495 (0.5%)
Annalyn's Infiltration Annalyn's Infiltration
48,043
444,868 (avg. 9.3)
35,697 (74.3%)
314 (0.7%)
Bird Watcher Bird Watcher
22,436
304,065 (avg. 13.6)
18,385 (81.9%)
480 (2.1%)
Karl's Languages Karl's Languages
14,840
83,850 (avg. 5.7)
13,297 (89.6%)
113 (0.8%)
Calculator Conundrum Calculator Conundrum
8,430
111,541 (avg. 13.2)
6,858 (81.4%)
115 (1.4%)
Squeaky Clean Squeaky Clean
17,397
253,513 (avg. 14.6)
11,716 (67.3%)
495 (2.8%)
Jedlik's Toy Car Jedlik's Toy Car
13,756
118,721 (avg. 8.6)
12,536 (91.1%)
154 (1.1%)
Need for Speed Need for Speed
10,525
130,445 (avg. 12.4)
9,169 (87.1%)
77 (0.7%)
Remote Control Competition Remote Control Competition
8,537
90,474 (avg. 10.6)
6,795 (79.6%)
103 (1.2%)
Cars, Assemble! Cars, Assemble!
20,827
153,932 (avg. 7.4)
18,676 (89.7%)
415 (2.0%)
Log Levels Log Levels
36,083
319,717 (avg. 8.9)
23,593 (65.4%)
302 (0.8%)
Salary Calculator Salary Calculator
11,864
69,718 (avg. 5.9)
11,000 (92.7%)
41 (0.3%)
Football Match Reports Football Match Reports
8,244
34,066 (avg. 4.1)
7,944 (96.4%)
56 (0.7%)
Wizards and Warriors Wizards and Warriors
7,874
57,812 (avg. 7.3)
7,157 (90.9%)
39 (0.5%)
Logs, Logs, Logs! Logs, Logs, Logs!
5,005
50,615 (avg. 10.1)
4,276 (85.4%)
61 (1.2%)
Tim from Marketing Tim from Marketing
8,079
53,178 (avg. 6.6)
7,623 (94.4%)
66 (0.8%)
Captain's Log Captain's Log
5,289
32,732 (avg. 6.2)
4,965 (93.9%)
21 (0.4%)
Booking Up For Beauty Booking Up For Beauty
6,225
82,690 (avg. 13.3)
5,153 (82.8%)
52 (0.8%)
Wizards and Warriors 2 Wizards and Warriors 2
3,926
34,207 (avg. 8.7)
3,563 (90.8%)
20 (0.5%)
Secrets Secrets
5,251
28,452 (avg. 5.4)
4,567 (87.0%)
7 (0.1%)
Gotta Snatch 'Em All Gotta Snatch 'Em All
4,041
48,322 (avg. 12.0)
3,478 (86.1%)
57 (1.4%)
International Calling Connoisseur International Calling Connoisseur
3,033
32,736 (avg. 10.8)
2,599 (85.7%)
28 (0.9%)
1 deprecated learning exercises
Started
Attempts
Completions
Mentoring requests
Play Your Cards! Play Your Cards!
8,676
85,962 (avg. 9.9)
6,859 (79.1%)
121 (1.4%)

Practice Exercises

Learn More

Practice Exercises are exercises designed to allow students to solve an arbitrary problem, with the aim of them making use of the concepts they have learned so far.

Synced primary repo: 9b54e9a017b84d2f62a9bbbe4f9f47dd55c2ab2d (Updates should be instant)

Next goal: Implement 139 practice exercises. Find out more.
136 active practice exercises
Started
Attempts
Completions
Mentoring requests
Hello World Hello World
222,434
450,550 (avg. 2.0)
136,523 (61.4%)
40 (0.0%)
Leap Leap
8,527
32,307 (avg. 3.8)
6,906 (81.0%)
118 (1.4%)
Reverse String Reverse String
16,181
48,805 (avg. 3.0)
13,525 (83.6%)
331 (2.0%)
Two Fer Two Fer
24,350
78,153 (avg. 3.2)
19,417 (79.7%)
3,928 (16.1%)
Armstrong Numbers Armstrong Numbers
7,666
27,142 (avg. 3.5)
6,148 (80.2%)
149 (1.9%)
Darts Darts
7,634
26,652 (avg. 3.5)
6,044 (79.2%)
67 (0.9%)
D&D Character D&D Character
5,157
42,994 (avg. 8.3)
3,651 (70.8%)
77 (1.5%)
DOT DSL DOT DSL
1,697
7,818 (avg. 4.6)
1,055 (62.2%)
8 (0.5%)
Grains Grains
5,131
40,325 (avg. 7.9)
4,167 (81.2%)
55 (1.1%)
High Scores High Scores
2,902
23,042 (avg. 7.9)
2,324 (80.1%)
38 (1.3%)
Resistor Color Resistor Color
6,864
25,969 (avg. 3.8)
5,560 (81.0%)
74 (1.1%)
Resistor Color Duo Resistor Color Duo
4,879
16,175 (avg. 3.3)
4,144 (84.9%)
47 (1.0%)
Resistor Color Trio Resistor Color Trio
1,868
20,975 (avg. 11.2)
1,589 (85.1%)
40 (2.1%)
RNA Transcription RNA Transcription
6,937
18,406 (avg. 2.7)
5,875 (84.7%)
243 (3.5%)
Acronym Acronym
4,884
21,444 (avg. 4.4)
3,924 (80.3%)
99 (2.0%)
Difference of Squares Difference of Squares
7,188
24,359 (avg. 3.4)
6,303 (87.7%)
711 (9.9%)
Gigasecond Gigasecond
8,773
20,963 (avg. 2.4)
6,334 (72.2%)
1,345 (15.3%)
Hamming Hamming
8,790
33,170 (avg. 3.8)
7,256 (82.5%)
1,495 (17.0%)
Micro Blog Micro Blog
6,981
39,169 (avg. 5.6)
4,312 (61.8%)
104 (1.5%)
Pangram Pangram
5,736
15,603 (avg. 2.7)
4,789 (83.5%)
173 (3.0%)
Perfect Numbers Perfect Numbers
3,764
14,478 (avg. 3.8)
2,676 (71.1%)
54 (1.4%)
Eliud's Eggs Eliud's Eggs
1,397
4,495 (avg. 3.2)
1,254 (89.8%)
17 (1.2%)
Protein Translation Protein Translation
3,872
20,123 (avg. 5.2)
3,056 (78.9%)
62 (1.6%)
Raindrops Raindrops
8,486
22,480 (avg. 2.6)
7,175 (84.6%)
258 (3.0%)
Say Say
2,917
19,647 (avg. 6.7)
1,343 (46.0%)
41 (1.4%)
Scrabble Score Scrabble Score
6,445
23,483 (avg. 3.6)
5,448 (84.5%)
1,085 (16.8%)
Secret Handshake Secret Handshake
4,374
21,904 (avg. 5.0)
3,368 (77.0%)
467 (10.7%)
Space Age Space Age
4,736
10,991 (avg. 2.3)
3,662 (77.3%)
65 (1.4%)
Collatz Conjecture Collatz Conjecture
2,393
9,511 (avg. 4.0)
1,976 (82.6%)
38 (1.6%)
Diamond Diamond
3,015
16,142 (avg. 5.4)
1,992 (66.1%)
57 (1.9%)
Error Handling Error Handling
2,104
15,041 (avg. 7.1)
1,224 (58.2%)
7 (0.3%)
ISBN Verifier ISBN Verifier
2,913
14,385 (avg. 4.9)
2,295 (78.8%)
44 (1.5%)
Isogram Isogram
5,343
20,477 (avg. 3.8)
4,333 (81.1%)
172 (3.2%)
Killer Sudoku Helper Killer Sudoku Helper
913
4,761 (avg. 5.2)
501 (54.9%)
18 (2.0%)
Kindergarten Garden Kindergarten Garden
1,447
5,089 (avg. 3.5)
1,074 (74.2%)
13 (0.9%)
Largest Series Product Largest Series Product
2,108
13,068 (avg. 6.2)
1,667 (79.1%)
23 (1.1%)
Luhn Luhn
2,793
13,896 (avg. 5.0)
2,178 (78.0%)
51 (1.8%)
Matrix Matrix
3,446
17,853 (avg. 5.2)
2,591 (75.2%)
314 (9.1%)
Nth Prime Nth Prime
1,629
6,331 (avg. 3.9)
1,268 (77.8%)
21 (1.3%)
Prism Prism
145
1,033 (avg. 7.1)
64 (44.1%)
0 (0.0%)
Proverb Proverb
2,988
8,867 (avg. 3.0)
2,427 (81.2%)
34 (1.1%)
Rate Limiter Rate Limiter
305
1,354 (avg. 4.4)
164 (53.8%)
4 (1.3%)
Rotational Cipher Rotational Cipher
2,594
13,083 (avg. 5.0)
2,176 (83.9%)
226 (8.7%)
Saddle Points Saddle Points
1,954
8,924 (avg. 4.6)
1,337 (68.4%)
161 (8.2%)
Sieve Sieve
1,601
4,635 (avg. 2.9)
1,273 (79.5%)
25 (1.6%)
Split-Second Stopwatch Split-Second Stopwatch
228
1,895 (avg. 8.3)
148 (64.9%)
0 (0.0%)
Sum of Multiples Sum of Multiples
2,208
8,016 (avg. 3.6)
1,625 (73.6%)
39 (1.8%)
Swift Scheduling Swift Scheduling
206
1,934 (avg. 9.4)
140 (68.0%)
1 (0.5%)
Triangle Triangle
3,050
12,366 (avg. 4.1)
2,590 (84.9%)
262 (8.6%)
Twelve Days Twelve Days
2,837
15,628 (avg. 5.5)
2,134 (75.2%)
33 (1.2%)
Variable Length Quantity Variable Length Quantity
766
3,060 (avg. 4.0)
400 (52.2%)
2 (0.3%)
Yacht Yacht
1,696
8,280 (avg. 4.9)
1,128 (66.5%)
31 (1.8%)
Allergies Allergies
1,444
5,116 (avg. 3.5)
1,088 (75.3%)
25 (1.7%)
Atbash Cipher Atbash Cipher
912
5,085 (avg. 5.6)
726 (79.6%)
8 (0.9%)
Bob Bob
2,276
13,867 (avg. 6.1)
1,845 (81.1%)
61 (2.7%)
Flatten Array Flatten Array
1,869
8,332 (avg. 4.5)
1,395 (74.6%)
137 (7.3%)
Conway's Game of Life Conway's Game of Life
501
2,342 (avg. 4.7)
314 (62.7%)
1 (0.2%)
Grep Grep
786
3,982 (avg. 5.1)
432 (55.0%)
7 (0.9%)
Knapsack Knapsack
1,029
4,759 (avg. 4.6)
609 (59.2%)
10 (1.0%)
Ledger Ledger
460
3,261 (avg. 7.1)
253 (55.0%)
9 (2.0%)
Matching Brackets Matching Brackets
907
3,457 (avg. 3.8)
650 (71.7%)
10 (1.1%)
Nucleotide Count Nucleotide Count
2,232
6,666 (avg. 3.0)
1,982 (88.8%)
91 (4.1%)
Pascal's Triangle Pascal's Triangle
891
2,452 (avg. 2.8)
635 (71.3%)
5 (0.6%)
Phone Number Phone Number
1,619
9,420 (avg. 5.8)
1,230 (76.0%)
26 (1.6%)
Pig Latin Pig Latin
2,773
12,269 (avg. 4.4)
1,552 (56.0%)
76 (2.7%)
Prime Factors Prime Factors
962
2,922 (avg. 3.0)
736 (76.5%)
11 (1.1%)
Relative Distance Relative Distance
941
5,603 (avg. 6.0)
399 (42.4%)
8 (0.9%)
Robot Name Robot Name
1,915
10,770 (avg. 5.6)
1,560 (81.5%)
139 (7.3%)
Run-Length Encoding Run-Length Encoding
723
3,154 (avg. 4.4)
515 (71.2%)
9 (1.2%)
Series Series
1,081
3,270 (avg. 3.0)
884 (81.8%)
11 (1.0%)
Square Root Square Root
635
1,917 (avg. 3.0)
501 (78.9%)
9 (1.4%)
Word Count Word Count
2,962
17,249 (avg. 5.8)
2,255 (76.1%)
212 (7.2%)
State Of Tic Tac Toe State Of Tic Tac Toe
379
2,579 (avg. 6.8)
229 (60.4%)
6 (1.6%)
Affine Cipher Affine Cipher
424
3,148 (avg. 7.4)
277 (65.3%)
4 (0.9%)
All Your Base All Your Base
572
2,922 (avg. 5.1)
389 (68.0%)
2 (0.3%)
Alphametics Alphametics
608
2,656 (avg. 4.4)
248 (40.8%)
3 (0.5%)
Baffling Birthdays Baffling Birthdays
89
410 (avg. 4.6)
52 (58.4%)
0 (0.0%)
Bank Account Bank Account
1,750
9,503 (avg. 5.4)
1,201 (68.6%)
96 (5.5%)
Binary Search Binary Search
1,414
7,806 (avg. 5.5)
1,064 (75.2%)
94 (6.6%)
Bottle Song Bottle Song
858
7,675 (avg. 8.9)
541 (63.1%)
19 (2.2%)
Bowling Bowling
1,017
8,270 (avg. 8.1)
437 (43.0%)
11 (1.1%)
Camicia Camicia
41
345 (avg. 8.4)
23 (56.1%)
0 (0.0%)
ETL ETL
1,869
2,912 (avg. 1.6)
1,682 (90.0%)
128 (6.8%)
Flower Field Flower Field
115
491 (avg. 4.3)
78 (67.8%)
0 (0.0%)
Food Chain Food Chain
931
3,541 (avg. 3.8)
623 (66.9%)
11 (1.2%)
Grade School Grade School
894
3,042 (avg. 3.4)
640 (71.6%)
22 (2.5%)
House House
1,004
3,761 (avg. 3.7)
718 (71.5%)
10 (1.0%)
Intergalactic Transmission Intergalactic Transmission
913
1,846 (avg. 2.0)
101 (11.1%)
5 (0.5%)
Linked List Linked List
1,466
6,354 (avg. 4.3)
1,034 (70.5%)
78 (5.3%)
Parallel Letter Frequency Parallel Letter Frequency
796
3,685 (avg. 4.6)
491 (61.7%)
13 (1.6%)
Piecing It Together Piecing It Together
82
761 (avg. 9.3)
42 (51.2%)
0 (0.0%)
Queen Attack Queen Attack
2,076
7,877 (avg. 3.8)
778 (37.5%)
34 (1.6%)
Rail Fence Cipher Rail Fence Cipher
402
1,567 (avg. 3.9)
242 (60.2%)
1 (0.2%)
REST API REST API
794
4,387 (avg. 5.5)
196 (24.7%)
5 (0.6%)
Robot Simulator Robot Simulator
859
2,750 (avg. 3.2)
543 (63.2%)
10 (1.2%)
Roman Numerals Roman Numerals
1,226
3,793 (avg. 3.1)
895 (73.0%)
15 (1.2%)
Spiral Matrix Spiral Matrix
633
1,607 (avg. 2.5)
397 (62.7%)
6 (0.9%)
Tournament Tournament
782
3,784 (avg. 4.8)
398 (50.9%)
10 (1.3%)
Transpose Transpose
579
2,964 (avg. 5.1)
316 (54.6%)
2 (0.3%)
Wordy Wordy
607
2,779 (avg. 4.6)
358 (59.0%)
6 (1.0%)
Anagram Anagram
3,200
10,467 (avg. 3.3)
2,298 (71.8%)
114 (3.6%)
Binary Search Tree Binary Search Tree
686
2,896 (avg. 4.2)
386 (56.3%)
9 (1.3%)
Clock Clock
573
2,390 (avg. 4.2)
386 (67.4%)
3 (0.5%)
Crypto Square Crypto Square
469
1,879 (avg. 4.0)
316 (67.4%)
3 (0.6%)
Dominoes Dominoes
1,098
3,192 (avg. 2.9)
293 (26.7%)
9 (0.8%)
Go Counting Go Counting
514
1,502 (avg. 2.9)
190 (37.0%)
0 (0.0%)
Markdown Markdown
952
2,238 (avg. 2.4)
394 (41.4%)
14 (1.5%)
Meetup Meetup
916
2,448 (avg. 2.7)
709 (77.4%)
13 (1.4%)
Poker Poker
778
2,691 (avg. 3.5)
237 (30.5%)
6 (0.8%)
SGF Parsing SGF Parsing
157
1,947 (avg. 12.4)
87 (55.4%)
2 (1.3%)
Simple Linked List Simple Linked List
785
4,049 (avg. 5.2)
470 (59.9%)
10 (1.3%)
Sublist Sublist
520
1,846 (avg. 3.6)
332 (63.8%)
0 (0.0%)
Tree Building Tree Building
350
845 (avg. 2.4)
160 (45.7%)
3 (0.9%)
Two Bucket Two Bucket
407
1,185 (avg. 2.9)
180 (44.2%)
3 (0.7%)
Word Search Word Search
897
2,578 (avg. 2.9)
284 (31.7%)
5 (0.6%)
Zebra Puzzle Zebra Puzzle
3,188
2,878 (avg. 0.9)
522 (16.4%)
12 (0.4%)
Zipper Zipper
331
966 (avg. 2.9)
146 (44.1%)
0 (0.0%)
Book Store Book Store
674
2,325 (avg. 3.4)
234 (34.7%)
6 (0.9%)
Change Change
575
3,383 (avg. 5.9)
241 (41.9%)
4 (0.7%)
Circular Buffer Circular Buffer
615
2,408 (avg. 3.9)
374 (60.8%)
5 (0.8%)
Complex Numbers Complex Numbers
665
2,314 (avg. 3.5)
417 (62.7%)
11 (1.7%)
Connect Connect
359
1,804 (avg. 5.0)
187 (52.1%)
7 (1.9%)
Hangman Hangman
378
1,129 (avg. 3.0)
101 (26.7%)
6 (1.6%)
List Ops List Ops
559
2,358 (avg. 4.2)
300 (53.7%)
9 (1.6%)
Mazy Mice Mazy Mice
155
716 (avg. 4.6)
71 (45.8%)
4 (2.6%)
OCR Numbers OCR Numbers
395
842 (avg. 2.1)
211 (53.4%)
3 (0.8%)
Palindrome Products Palindrome Products
483
1,464 (avg. 3.0)
256 (53.0%)
5 (1.0%)
POV POV
169
780 (avg. 4.6)
82 (48.5%)
1 (0.6%)
Rational Numbers Rational Numbers
524
3,367 (avg. 6.4)
282 (53.8%)
6 (1.1%)
React React
275
1,137 (avg. 4.1)
90 (32.7%)
2 (0.7%)
Rectangles Rectangles
374
886 (avg. 2.4)
188 (50.3%)
4 (1.1%)
Simple Cipher Simple Cipher
537
1,806 (avg. 3.4)
347 (64.6%)
7 (1.3%)
Forth Forth
529
1,849 (avg. 3.5)
217 (41.0%)
13 (2.5%)
Pythagorean Triplet Pythagorean Triplet
1,087
6,718 (avg. 6.2)
472 (43.4%)
7 (0.6%)
Custom Set Custom Set
596
2,096 (avg. 3.5)
268 (45.0%)
5 (0.8%)
Satellite Satellite
530
1,131 (avg. 2.1)
179 (33.8%)
4 (0.8%)
9 deprecated practice exercises
Started
Attempts
Completions
Mentoring requests
Accumulate Accumulate
110
138 (avg. 1.3)
107 (97.3%)
5 (4.5%)
Beer Song Beer Song
867
3,388 (avg. 3.9)
664 (76.6%)
15 (1.7%)
Binary Binary
136
181 (avg. 1.3)
134 (98.5%)
6 (4.4%)
Diffie-Hellman Diffie-Hellman
228
327 (avg. 1.4)
117 (51.3%)
2 (0.9%)
Hexadecimal Hexadecimal
58
74 (avg. 1.3)
56 (96.6%)
7 (12.1%)
Minesweeper Minesweeper
795
2,853 (avg. 3.6)
519 (65.3%)
9 (1.1%)
Octal Octal
59
70 (avg. 1.2)
57 (96.6%)
2 (3.4%)
Strain Strain
111
141 (avg. 1.3)
108 (97.3%)
5 (4.5%)
Trinary Trinary
71
85 (avg. 1.2)
69 (97.2%)
1 (1.4%)
3 unimplemented practice exercises
Line Up Line Up
View dataThe link opens in a new window or tab
PaaS I/O PaaS I/O
View dataThe link opens in a new window or tab
Save the Cow Save the Cow
View dataThe link opens in a new window or tab
1 foregone practice exercise
Lens Person Lens Person
View dataThe link opens in a new window or tab

Test Runner

Learn More

Create Test Runners that have the single responsibility of taking a solution, running all tests and returning a standardized output.

Current version: 149e8132a1ca50237d80ccbf402cc1104dc41eb1 (Takes up to 10 mins to deploy)

Total Test Runner Runs
4,789,330
Test Run Pass Rate
17.3% (827071)
Test Run Fail Rate
38.1% (1827018)
Test Run Error Rate
44.6% (2135241)

Representer

Learn More

Build a Representer: a bit of code that has the single responsibility of taking a solution and returning a normalized representation of it.

Current version: c84371546bbb96407e400b7e18d7fcc204a0b29c (Takes up to 10 mins to deploy)

Total Representer Runs
944,551
Total Representation Comments Made
108,984
Feedback Given Frequency
11.5%

Analyzer

Learn More

Build an Analyzer for Java: Exercism's analyzers automatically assess student's submissions and provide mentor-style commentary.

Current version: 3b609b65df1ca5622fea622d4d1169013ad1f7a5 (Takes up to 10 mins to deploy)

Total Analyzer Runs
659,830
Total Analysis Comments Made
426,140
Feedback Given Frequency
4.3%