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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
284,250
Submissions
4,898,932
Mentoring Discussions
17,750

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
61,965 learnt
Bo
Booleans
35,929 learnt
Ar
Arrays
18,507 learnt
Fo
For Loops
18,507 learnt
Fo
For-Each Loops
18,507 learnt
Ge
Generic Types
13,386 learnt
Li
Lists
13,386 learnt
Ex
Exceptions
6,916 learnt
Ch
Chars
11,776 learnt
Cl
Classes
12,651 learnt
Co
Constructors
9,252 learnt
In
Interfaces
6,833 learnt
If
If-Else Statements
18,823 learnt
Nu
Numbers
18,823 learnt
St
Strings
23,723 learnt
Te
Ternary Operators
11,083 learnt
Sw
Switch Statements
7,997 learnt
In
Inheritance
7,221 learnt
En
Enums
4,302 learnt
Nu
Nullability
7,697 learnt
Ra
Randomness
5,007 learnt
Da
Date-Time
5,196 learnt
Me
Method Overloading
3,587 learnt
Bi
Bit Manipulation
4,602 learnt
Se
Sets
3,505 learnt
Ma
Maps
2,629 learnt
22 active learning exercises
Started
Attempts
Completions
Mentoring requests
Cook Your Lasagna Cook Your Lasagna
102,299
558,596 (avg. 5.5)
61,965 (60.6%)
496 (0.5%)
Annalyn's Infiltration Annalyn's Infiltration
48,326
447,007 (avg. 9.2)
35,929 (74.3%)
315 (0.7%)
Bird Watcher Bird Watcher
22,588
305,825 (avg. 13.5)
18,507 (81.9%)
483 (2.1%)
Karl's Languages Karl's Languages
14,936
84,420 (avg. 5.7)
13,386 (89.6%)
113 (0.8%)
Calculator Conundrum Calculator Conundrum
8,497
112,310 (avg. 13.2)
6,916 (81.4%)
116 (1.4%)
Squeaky Clean Squeaky Clean
17,472
254,308 (avg. 14.6)
11,776 (67.4%)
497 (2.8%)
Jedlik's Toy Car Jedlik's Toy Car
13,881
119,492 (avg. 8.6)
12,651 (91.1%)
154 (1.1%)
Need for Speed Need for Speed
10,628
131,534 (avg. 12.4)
9,252 (87.1%)
77 (0.7%)
Remote Control Competition Remote Control Competition
8,589
90,805 (avg. 10.6)
6,833 (79.6%)
103 (1.2%)
Cars, Assemble! Cars, Assemble!
20,983
154,830 (avg. 7.4)
18,823 (89.7%)
422 (2.0%)
Log Levels Log Levels
36,278
320,959 (avg. 8.8)
23,723 (65.4%)
302 (0.8%)
Salary Calculator Salary Calculator
11,950
70,221 (avg. 5.9)
11,083 (92.7%)
42 (0.4%)
Football Match Reports Football Match Reports
8,300
34,230 (avg. 4.1)
7,997 (96.3%)
57 (0.7%)
Wizards and Warriors Wizards and Warriors
7,943
58,280 (avg. 7.3)
7,221 (90.9%)
39 (0.5%)
Logs, Logs, Logs! Logs, Logs, Logs!
5,033
50,883 (avg. 10.1)
4,302 (85.5%)
62 (1.2%)
Tim from Marketing Tim from Marketing
8,156
53,591 (avg. 6.6)
7,697 (94.4%)
66 (0.8%)
Captain's Log Captain's Log
5,333
32,943 (avg. 6.2)
5,007 (93.9%)
21 (0.4%)
Booking Up For Beauty Booking Up For Beauty
6,286
83,269 (avg. 13.2)
5,196 (82.7%)
53 (0.8%)
Wizards and Warriors 2 Wizards and Warriors 2
3,949
34,410 (avg. 8.7)
3,587 (90.8%)
20 (0.5%)
Secrets Secrets
5,292
28,602 (avg. 5.4)
4,602 (87.0%)
7 (0.1%)
Gotta Snatch 'Em All Gotta Snatch 'Em All
4,073
48,647 (avg. 11.9)
3,505 (86.1%)
58 (1.4%)
International Calling Connoisseur International Calling Connoisseur
3,064
33,055 (avg. 10.8)
2,629 (85.8%)
30 (1.0%)
1 deprecated learning exercises
Started
Attempts
Completions
Mentoring requests
Play Your Cards! Play Your Cards!
8,676
85,964 (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: 8a16b1bb7fe63ab57bc57789e3fcce34063a7371 (Updates should be instant)

Next goal: Implement 140 practice exercises. Find out more.
136 active practice exercises
Started
Attempts
Completions
Mentoring requests
Hello World Hello World
223,437
452,574 (avg. 2.0)
137,139 (61.4%)
40 (0.0%)
Leap Leap
8,572
32,472 (avg. 3.8)
6,947 (81.0%)
119 (1.4%)
Reverse String Reverse String
16,213
48,944 (avg. 3.0)
13,556 (83.6%)
331 (2.0%)
Two Fer Two Fer
24,389
78,268 (avg. 3.2)
19,449 (79.7%)
3,928 (16.1%)
Armstrong Numbers Armstrong Numbers
7,699
27,348 (avg. 3.6)
6,177 (80.2%)
150 (1.9%)
Darts Darts
7,666
26,745 (avg. 3.5)
6,068 (79.2%)
67 (0.9%)
D&D Character D&D Character
5,174
43,140 (avg. 8.3)
3,658 (70.7%)
77 (1.5%)
DOT DSL DOT DSL
1,712
7,985 (avg. 4.7)
1,068 (62.4%)
9 (0.5%)
Grains Grains
5,162
40,585 (avg. 7.9)
4,192 (81.2%)
55 (1.1%)
High Scores High Scores
2,921
23,155 (avg. 7.9)
2,337 (80.0%)
38 (1.3%)
Resistor Color Resistor Color
6,878
26,055 (avg. 3.8)
5,577 (81.1%)
74 (1.1%)
Resistor Color Duo Resistor Color Duo
4,891
16,235 (avg. 3.3)
4,156 (85.0%)
47 (1.0%)
Resistor Color Trio Resistor Color Trio
1,879
21,108 (avg. 11.2)
1,599 (85.1%)
40 (2.1%)
RNA Transcription RNA Transcription
6,944
18,444 (avg. 2.7)
5,882 (84.7%)
243 (3.5%)
Acronym Acronym
4,894
21,582 (avg. 4.4)
3,934 (80.4%)
99 (2.0%)
Difference of Squares Difference of Squares
7,202
24,420 (avg. 3.4)
6,316 (87.7%)
711 (9.9%)
Gigasecond Gigasecond
8,787
21,010 (avg. 2.4)
6,344 (72.2%)
1,345 (15.3%)
Hamming Hamming
8,803
33,232 (avg. 3.8)
7,268 (82.6%)
1,495 (17.0%)
Micro Blog Micro Blog
7,000
39,313 (avg. 5.6)
4,324 (61.8%)
104 (1.5%)
Pangram Pangram
5,745
15,720 (avg. 2.7)
4,801 (83.6%)
173 (3.0%)
Perfect Numbers Perfect Numbers
3,775
14,603 (avg. 3.9)
2,685 (71.1%)
54 (1.4%)
Eliud's Eggs Eliud's Eggs
1,405
4,530 (avg. 3.2)
1,262 (89.8%)
17 (1.2%)
Protein Translation Protein Translation
3,880
20,264 (avg. 5.2)
3,064 (79.0%)
62 (1.6%)
Raindrops Raindrops
8,500
22,544 (avg. 2.7)
7,187 (84.6%)
258 (3.0%)
Say Say
2,929
19,712 (avg. 6.7)
1,349 (46.1%)
42 (1.4%)
Scrabble Score Scrabble Score
6,455
23,533 (avg. 3.6)
5,456 (84.5%)
1,085 (16.8%)
Secret Handshake Secret Handshake
4,378
21,933 (avg. 5.0)
3,372 (77.0%)
467 (10.7%)
Space Age Space Age
4,744
11,006 (avg. 2.3)
3,668 (77.3%)
65 (1.4%)
Collatz Conjecture Collatz Conjecture
2,404
9,562 (avg. 4.0)
1,984 (82.5%)
38 (1.6%)
Diamond Diamond
3,021
16,159 (avg. 5.3)
2,000 (66.2%)
57 (1.9%)
Error Handling Error Handling
2,112
15,110 (avg. 7.2)
1,229 (58.2%)
7 (0.3%)
ISBN Verifier ISBN Verifier
2,924
14,433 (avg. 4.9)
2,304 (78.8%)
44 (1.5%)
Isogram Isogram
5,353
20,521 (avg. 3.8)
4,342 (81.1%)
172 (3.2%)
Killer Sudoku Helper Killer Sudoku Helper
918
4,783 (avg. 5.2)
505 (55.0%)
18 (2.0%)
Kindergarten Garden Kindergarten Garden
1,450
5,105 (avg. 3.5)
1,077 (74.3%)
13 (0.9%)
Largest Series Product Largest Series Product
2,113
13,158 (avg. 6.2)
1,672 (79.1%)
23 (1.1%)
Luhn Luhn
2,797
13,960 (avg. 5.0)
2,184 (78.1%)
51 (1.8%)
Matrix Matrix
3,454
17,896 (avg. 5.2)
2,597 (75.2%)
314 (9.1%)
Nth Prime Nth Prime
1,635
6,393 (avg. 3.9)
1,276 (78.0%)
22 (1.3%)
Prism Prism
150
1,042 (avg. 6.9)
70 (46.7%)
0 (0.0%)
Proverb Proverb
2,995
8,874 (avg. 3.0)
2,432 (81.2%)
34 (1.1%)
Rate Limiter Rate Limiter
312
1,395 (avg. 4.5)
170 (54.5%)
4 (1.3%)
Rotational Cipher Rotational Cipher
2,598
13,093 (avg. 5.0)
2,180 (83.9%)
226 (8.7%)
Saddle Points Saddle Points
1,959
8,928 (avg. 4.6)
1,339 (68.4%)
161 (8.2%)
Sieve Sieve
1,607
4,686 (avg. 2.9)
1,277 (79.5%)
25 (1.6%)
Split-Second Stopwatch Split-Second Stopwatch
232
1,932 (avg. 8.3)
151 (65.1%)
0 (0.0%)
Sum of Multiples Sum of Multiples
2,214
8,043 (avg. 3.6)
1,631 (73.7%)
39 (1.8%)
Swift Scheduling Swift Scheduling
209
1,978 (avg. 9.5)
142 (67.9%)
1 (0.5%)
Triangle Triangle
3,056
12,396 (avg. 4.1)
2,594 (84.9%)
262 (8.6%)
Twelve Days Twelve Days
2,838
15,630 (avg. 5.5)
2,135 (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
1,697
8,282 (avg. 4.9)
1,128 (66.5%)
31 (1.8%)
Allergies Allergies
1,444
5,117 (avg. 3.5)
1,089 (75.4%)
25 (1.7%)
Atbash Cipher Atbash Cipher
913
5,087 (avg. 5.6)
727 (79.6%)
8 (0.9%)
Bob Bob
2,279
13,871 (avg. 6.1)
1,847 (81.0%)
61 (2.7%)
Flatten Array Flatten Array
1,873
8,341 (avg. 4.5)
1,398 (74.6%)
137 (7.3%)
Conway's Game of Life Conway's Game of Life
505
2,363 (avg. 4.7)
317 (62.8%)
1 (0.2%)
Grep Grep
787
3,983 (avg. 5.1)
433 (55.0%)
7 (0.9%)
Knapsack Knapsack
1,030
4,767 (avg. 4.6)
610 (59.2%)
10 (1.0%)
Ledger Ledger
461
3,262 (avg. 7.1)
254 (55.1%)
9 (2.0%)
Matching Brackets Matching Brackets
910
3,470 (avg. 3.8)
653 (71.8%)
10 (1.1%)
Nucleotide Count Nucleotide Count
2,236
6,681 (avg. 3.0)
1,985 (88.8%)
91 (4.1%)
Pascal's Triangle Pascal's Triangle
892
2,462 (avg. 2.8)
636 (71.3%)
5 (0.6%)
Phone Number Phone Number
1,621
9,428 (avg. 5.8)
1,232 (76.0%)
26 (1.6%)
Pig Latin Pig Latin
2,774
12,273 (avg. 4.4)
1,553 (56.0%)
76 (2.7%)
Prime Factors Prime Factors
963
2,925 (avg. 3.0)
737 (76.5%)
11 (1.1%)
Relative Distance Relative Distance
954
5,721 (avg. 6.0)
407 (42.7%)
8 (0.8%)
Robot Name Robot Name
1,917
10,773 (avg. 5.6)
1,562 (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
1,082
3,278 (avg. 3.0)
885 (81.8%)
11 (1.0%)
Square Root Square Root
637
1,922 (avg. 3.0)
502 (78.8%)
9 (1.4%)
Word Count Word Count
2,969
17,267 (avg. 5.8)
2,257 (76.0%)
213 (7.2%)
State Of Tic Tac Toe State Of Tic Tac Toe
380
2,579 (avg. 6.8)
229 (60.3%)
6 (1.6%)
Affine Cipher Affine Cipher
425
3,164 (avg. 7.4)
278 (65.4%)
4 (0.9%)
All Your Base All Your Base
573
2,941 (avg. 5.1)
390 (68.1%)
2 (0.3%)
Alphametics Alphametics
609
2,657 (avg. 4.4)
249 (40.9%)
3 (0.5%)
Baffling Birthdays Baffling Birthdays
91
412 (avg. 4.5)
54 (59.3%)
0 (0.0%)
Bank Account Bank Account
1,751
9,510 (avg. 5.4)
1,203 (68.7%)
96 (5.5%)
Binary Search Binary Search
1,418
7,829 (avg. 5.5)
1,068 (75.3%)
94 (6.6%)
Bottle Song Bottle Song
862
7,698 (avg. 8.9)
545 (63.2%)
19 (2.2%)
Bowling Bowling
1,019
8,271 (avg. 8.1)
438 (43.0%)
11 (1.1%)
Camicia Camicia
43
347 (avg. 8.1)
25 (58.1%)
0 (0.0%)
ETL ETL
1,871
2,935 (avg. 1.6)
1,684 (90.0%)
128 (6.8%)
Flower Field Flower Field
117
492 (avg. 4.2)
79 (67.5%)
0 (0.0%)
Food Chain Food Chain
931
3,541 (avg. 3.8)
623 (66.9%)
11 (1.2%)
Grade School Grade School
897
3,076 (avg. 3.4)
642 (71.6%)
22 (2.5%)
House House
1,004
3,761 (avg. 3.7)
718 (71.5%)
10 (1.0%)
Intergalactic Transmission Intergalactic Transmission
941
1,870 (avg. 2.0)
103 (10.9%)
5 (0.5%)
Linked List Linked List
1,468
6,366 (avg. 4.3)
1,035 (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
83
761 (avg. 9.2)
42 (50.6%)
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
797
4,433 (avg. 5.6)
199 (25.0%)
5 (0.6%)
Robot Simulator Robot Simulator
861
2,760 (avg. 3.2)
545 (63.3%)
10 (1.2%)
Roman Numerals Roman Numerals
1,228
3,793 (avg. 3.1)
895 (72.9%)
15 (1.2%)
Spiral Matrix Spiral Matrix
634
1,609 (avg. 2.5)
398 (62.8%)
6 (0.9%)
Tournament Tournament
787
3,960 (avg. 5.0)
400 (50.8%)
10 (1.3%)
Transpose Transpose
579
2,972 (avg. 5.1)
316 (54.6%)
2 (0.3%)
Wordy Wordy
608
2,788 (avg. 4.6)
359 (59.0%)
6 (1.0%)
Anagram Anagram
3,203
10,520 (avg. 3.3)
2,303 (71.9%)
114 (3.6%)
Binary Search Tree Binary Search Tree
690
2,937 (avg. 4.3)
389 (56.4%)
9 (1.3%)
Clock Clock
576
2,409 (avg. 4.2)
387 (67.2%)
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
953
2,238 (avg. 2.3)
394 (41.3%)
14 (1.5%)
Meetup Meetup
916
2,448 (avg. 2.7)
709 (77.4%)
13 (1.4%)
Poker Poker
779
2,691 (avg. 3.5)
237 (30.4%)
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
788
4,068 (avg. 5.2)
472 (59.9%)
10 (1.3%)
Sublist Sublist
520
1,846 (avg. 3.6)
332 (63.8%)
0 (0.0%)
Tree Building Tree Building
351
845 (avg. 2.4)
160 (45.6%)
3 (0.9%)
Two Bucket Two Bucket
408
1,185 (avg. 2.9)
180 (44.1%)
3 (0.7%)
Word Search Word Search
898
2,604 (avg. 2.9)
284 (31.6%)
5 (0.6%)
Zebra Puzzle Zebra Puzzle
3,205
2,890 (avg. 0.9)
525 (16.4%)
12 (0.4%)
Zipper Zipper
332
968 (avg. 2.9)
146 (44.0%)
0 (0.0%)
Book Store Book Store
674
2,325 (avg. 3.4)
234 (34.7%)
6 (0.9%)
Change Change
577
3,391 (avg. 5.9)
241 (41.8%)
4 (0.7%)
Circular Buffer Circular Buffer
617
2,458 (avg. 4.0)
376 (60.9%)
5 (0.8%)
Complex Numbers Complex Numbers
667
2,314 (avg. 3.5)
417 (62.5%)
11 (1.6%)
Connect Connect
359
1,804 (avg. 5.0)
187 (52.1%)
7 (1.9%)
Hangman Hangman
379
1,129 (avg. 3.0)
101 (26.6%)
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
484
1,491 (avg. 3.1)
257 (53.1%)
5 (1.0%)
POV POV
169
780 (avg. 4.6)
82 (48.5%)
1 (0.6%)
Rational Numbers Rational Numbers
526
3,369 (avg. 6.4)
283 (53.8%)
6 (1.1%)
React React
277
1,138 (avg. 4.1)
90 (32.5%)
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
530
1,891 (avg. 3.6)
217 (40.9%)
13 (2.5%)
Pythagorean Triplet Pythagorean Triplet
1,088
6,718 (avg. 6.2)
472 (43.4%)
7 (0.6%)
Custom Set Custom Set
600
2,096 (avg. 3.5)
268 (44.7%)
5 (0.8%)
Satellite Satellite
532
1,135 (avg. 2.1)
179 (33.6%)
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%)
4 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
Resistor Color Tolerance Resistor Color Tolerance
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
4,812,599
Test Run Pass Rate
17.3% (831318)
Test Run Fail Rate
38.1% (1835526)
Test Run Error Rate
44.6% (2145755)

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
948,455
Total Representation Comments Made
110,000
Feedback Given Frequency
11.6%

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
663,731
Total Analysis Comments Made
429,232
Feedback Given Frequency
4.3%