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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
286,436
Submissions
4,954,440
Mentoring Discussions
17,800

The Java track is healthy ✅

Building

Java syllabus

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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.
27 concepts being taught
Ba
Basics
62,684 learnt
Bo
Booleans
36,368 learnt
Ar
Arrays
18,810 learnt
Fo
For Loops
18,810 learnt
Fo
For-Each Loops
18,810 learnt
Ge
Generic Types
13,612 learnt
Li
Lists
13,612 learnt
Ex
Exceptions
7,076 learnt
Ch
Chars
11,940 learnt
Cl
Classes
12,882 learnt
Co
Constructors
9,423 learnt
In
Interfaces
6,984 learnt
If
If-Else Statements
19,110 learnt
Nu
Numbers
19,110 learnt
St
Strings
24,028 learnt
Te
Ternary Operators
11,254 learnt
Sw
Switch Statements
8,139 learnt
In
Inheritance
7,345 learnt
En
Enums
4,391 learnt
Nu
Nullability
7,849 learnt
Ra
Randomness
5,107 learnt
Da
Date-Time
5,295 learnt
Me
Method Overloading
3,655 learnt
Bi
Bit Manipulation
4,698 learnt
Se
Sets
3,577 learnt
Ma
Maps
2,713 learnt
Te
Temporal Adjusters
44 learnt
23 active learning exercises
Started
Attempts
Completions
Mentoring requests
Cook Your Lasagna Cook Your Lasagna
103,449
564,545 (avg. 5.5)
62,684 (60.6%)
497 (0.5%)
Annalyn's Infiltration Annalyn's Infiltration
48,917
451,094 (avg. 9.2)
36,368 (74.3%)
315 (0.6%)
Bird Watcher Bird Watcher
22,951
310,729 (avg. 13.5)
18,810 (82.0%)
488 (2.1%)
Karl's Languages Karl's Languages
15,192
85,703 (avg. 5.6)
13,612 (89.6%)
118 (0.8%)
Calculator Conundrum Calculator Conundrum
8,684
114,164 (avg. 13.1)
7,076 (81.5%)
118 (1.4%)
Squeaky Clean Squeaky Clean
17,664
256,040 (avg. 14.5)
11,940 (67.6%)
500 (2.8%)
Jedlik's Toy Car Jedlik's Toy Car
14,143
121,464 (avg. 8.6)
12,882 (91.1%)
157 (1.1%)
Need for Speed Need for Speed
10,841
133,491 (avg. 12.3)
9,423 (86.9%)
80 (0.7%)
Remote Control Competition Remote Control Competition
8,792
92,469 (avg. 10.5)
6,984 (79.4%)
105 (1.2%)
Cars, Assemble! Cars, Assemble!
21,296
156,934 (avg. 7.4)
19,110 (89.7%)
426 (2.0%)
Log Levels Log Levels
36,676
324,277 (avg. 8.8)
24,028 (65.5%)
303 (0.8%)
Salary Calculator Salary Calculator
12,143
71,122 (avg. 5.9)
11,254 (92.7%)
43 (0.4%)
Football Match Reports Football Match Reports
8,448
34,750 (avg. 4.1)
8,139 (96.3%)
58 (0.7%)
Wizards and Warriors Wizards and Warriors
8,082
59,304 (avg. 7.3)
7,345 (90.9%)
39 (0.5%)
Logs, Logs, Logs! Logs, Logs, Logs!
5,147
51,758 (avg. 10.1)
4,391 (85.3%)
62 (1.2%)
Tim from Marketing Tim from Marketing
8,317
54,606 (avg. 6.6)
7,849 (94.4%)
66 (0.8%)
Captain's Log Captain's Log
5,431
33,550 (avg. 6.2)
5,107 (94.0%)
21 (0.4%)
Booking Up For Beauty Booking Up For Beauty
6,402
84,494 (avg. 13.2)
5,295 (82.7%)
53 (0.8%)
Wizards and Warriors 2 Wizards and Warriors 2
4,020
34,961 (avg. 8.7)
3,655 (90.9%)
21 (0.5%)
Secrets Secrets
5,395
29,117 (avg. 5.4)
4,698 (87.1%)
7 (0.1%)
Gotta Snatch 'Em All Gotta Snatch 'Em All
4,153
49,353 (avg. 11.9)
3,577 (86.1%)
58 (1.4%)
International Calling Connoisseur International Calling Connoisseur
3,163
33,916 (avg. 10.7)
2,713 (85.8%)
33 (1.0%)
Beauty Salon Regulars Beauty Salon Regulars
67
621 (avg. 9.3)
44 (65.7%)
1 (1.5%)
1 deprecated learning exercises
Started
Attempts
Completions
Mentoring requests
Play Your Cards! Play Your Cards!
8,676
85,974 (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: be2d006c30c50e0154231dd987d5a3b5526c0427 (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
225,609
456,736 (avg. 2.0)
138,461 (61.4%)
40 (0.0%)
Leap Leap
8,691
32,996 (avg. 3.8)
7,044 (81.0%)
119 (1.4%)
Reverse String Reverse String
16,298
49,211 (avg. 3.0)
13,633 (83.6%)
331 (2.0%)
Two Fer Two Fer
24,480
78,602 (avg. 3.2)
19,530 (79.8%)
3,929 (16.0%)
Armstrong Numbers Armstrong Numbers
7,787
27,705 (avg. 3.6)
6,258 (80.4%)
151 (1.9%)
Darts Darts
7,755
26,992 (avg. 3.5)
6,138 (79.1%)
67 (0.9%)
D&D Character D&D Character
5,231
43,721 (avg. 8.4)
3,712 (71.0%)
78 (1.5%)
DOT DSL DOT DSL
1,766
8,204 (avg. 4.6)
1,108 (62.7%)
9 (0.5%)
Grains Grains
5,232
41,084 (avg. 7.9)
4,252 (81.3%)
55 (1.1%)
High Scores High Scores
2,983
23,601 (avg. 7.9)
2,388 (80.1%)
38 (1.3%)
Resistor Color Resistor Color
6,940
26,264 (avg. 3.8)
5,632 (81.2%)
74 (1.1%)
Resistor Color Duo Resistor Color Duo
4,942
16,448 (avg. 3.3)
4,202 (85.0%)
47 (1.0%)
Resistor Color Trio Resistor Color Trio
1,928
21,501 (avg. 11.2)
1,643 (85.2%)
40 (2.1%)
RNA Transcription RNA Transcription
6,992
18,612 (avg. 2.7)
5,927 (84.8%)
243 (3.5%)
Acronym Acronym
4,955
21,891 (avg. 4.4)
3,984 (80.4%)
99 (2.0%)
Difference of Squares Difference of Squares
7,252
24,577 (avg. 3.4)
6,364 (87.8%)
711 (9.8%)
Gigasecond Gigasecond
8,827
21,071 (avg. 2.4)
6,379 (72.3%)
1,345 (15.2%)
Hamming Hamming
8,848
33,473 (avg. 3.8)
7,310 (82.6%)
1,495 (16.9%)
Micro Blog Micro Blog
7,051
39,530 (avg. 5.6)
4,361 (61.8%)
104 (1.5%)
Pangram Pangram
5,779
15,851 (avg. 2.7)
4,832 (83.6%)
173 (3.0%)
Perfect Numbers Perfect Numbers
3,806
14,741 (avg. 3.9)
2,713 (71.3%)
54 (1.4%)
Eliud's Eggs Eliud's Eggs
1,440
4,663 (avg. 3.2)
1,296 (90.0%)
17 (1.2%)
Protein Translation Protein Translation
3,917
20,581 (avg. 5.3)
3,097 (79.1%)
62 (1.6%)
Raindrops Raindrops
8,557
22,798 (avg. 2.7)
7,239 (84.6%)
258 (3.0%)
Say Say
2,956
20,006 (avg. 6.8)
1,374 (46.5%)
42 (1.4%)
Scrabble Score Scrabble Score
6,485
23,662 (avg. 3.6)
5,484 (84.6%)
1,085 (16.7%)
Secret Handshake Secret Handshake
4,407
22,142 (avg. 5.0)
3,400 (77.1%)
468 (10.6%)
Space Age Space Age
4,776
11,124 (avg. 2.3)
3,696 (77.4%)
65 (1.4%)
Collatz Conjecture Collatz Conjecture
2,433
9,718 (avg. 4.0)
2,008 (82.5%)
38 (1.6%)
Diamond Diamond
3,047
16,341 (avg. 5.4)
2,018 (66.2%)
57 (1.9%)
Error Handling Error Handling
2,136
15,298 (avg. 7.2)
1,250 (58.5%)
7 (0.3%)
ISBN Verifier ISBN Verifier
2,941
14,543 (avg. 4.9)
2,319 (78.9%)
44 (1.5%)
Isogram Isogram
5,383
20,649 (avg. 3.8)
4,367 (81.1%)
172 (3.2%)
Killer Sudoku Helper Killer Sudoku Helper
931
4,999 (avg. 5.4)
513 (55.1%)
18 (1.9%)
Kindergarten Garden Kindergarten Garden
1,462
5,176 (avg. 3.5)
1,088 (74.4%)
13 (0.9%)
Largest Series Product Largest Series Product
2,126
13,227 (avg. 6.2)
1,682 (79.1%)
23 (1.1%)
Luhn Luhn
2,815
14,052 (avg. 5.0)
2,198 (78.1%)
51 (1.8%)
Matrix Matrix
3,465
17,967 (avg. 5.2)
2,606 (75.2%)
314 (9.1%)
Nth Prime Nth Prime
1,644
6,427 (avg. 3.9)
1,285 (78.2%)
22 (1.3%)
Prism Prism
165
1,162 (avg. 7.0)
77 (46.7%)
1 (0.6%)
Proverb Proverb
3,005
8,953 (avg. 3.0)
2,441 (81.2%)
34 (1.1%)
Rate Limiter Rate Limiter
332
1,450 (avg. 4.4)
181 (54.5%)
5 (1.5%)
Rotational Cipher Rotational Cipher
2,606
13,151 (avg. 5.0)
2,186 (83.9%)
226 (8.7%)
Saddle Points Saddle Points
1,961
8,965 (avg. 4.6)
1,342 (68.4%)
161 (8.2%)
Sieve Sieve
1,620
4,737 (avg. 2.9)
1,285 (79.3%)
25 (1.5%)
Split-Second Stopwatch Split-Second Stopwatch
237
1,955 (avg. 8.2)
156 (65.8%)
0 (0.0%)
Sum of Multiples Sum of Multiples
2,224
8,099 (avg. 3.6)
1,639 (73.7%)
40 (1.8%)
Swift Scheduling Swift Scheduling
214
1,991 (avg. 9.3)
147 (68.7%)
1 (0.5%)
Triangle Triangle
3,063
12,438 (avg. 4.1)
2,601 (84.9%)
262 (8.6%)
Twelve Days Twelve Days
2,846
15,695 (avg. 5.5)
2,142 (75.3%)
33 (1.2%)
Variable Length Quantity Variable Length Quantity
770
3,083 (avg. 4.0)
404 (52.5%)
2 (0.3%)
Yacht Yacht
1,700
8,304 (avg. 4.9)
1,130 (66.5%)
31 (1.8%)
Allergies Allergies
1,452
5,148 (avg. 3.5)
1,095 (75.4%)
25 (1.7%)
Atbash Cipher Atbash Cipher
917
5,110 (avg. 5.6)
729 (79.5%)
9 (1.0%)
Bob Bob
2,301
14,162 (avg. 6.2)
1,862 (80.9%)
62 (2.7%)
Flatten Array Flatten Array
1,882
8,369 (avg. 4.4)
1,400 (74.4%)
137 (7.3%)
Conway's Game of Life Conway's Game of Life
510
2,377 (avg. 4.7)
322 (63.1%)
2 (0.4%)
Grep Grep
789
3,993 (avg. 5.1)
435 (55.1%)
7 (0.9%)
Knapsack Knapsack
1,032
4,768 (avg. 4.6)
611 (59.2%)
10 (1.0%)
Ledger Ledger
463
3,267 (avg. 7.1)
255 (55.1%)
9 (1.9%)
Matching Brackets Matching Brackets
913
3,494 (avg. 3.8)
655 (71.7%)
11 (1.2%)
Nucleotide Count Nucleotide Count
2,240
6,720 (avg. 3.0)
1,988 (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
9,429 (avg. 5.8)
1,232 (76.0%)
26 (1.6%)
Pig Latin Pig Latin
2,774
12,274 (avg. 4.4)
1,553 (56.0%)
76 (2.7%)
Prime Factors Prime Factors
966
2,926 (avg. 3.0)
738 (76.4%)
11 (1.1%)
Relative Distance Relative Distance
991
5,975 (avg. 6.0)
428 (43.2%)
9 (0.9%)
Robot Name Robot Name
1,922
10,788 (avg. 5.6)
1,564 (81.4%)
139 (7.2%)
Run-Length Encoding Run-Length Encoding
724
3,161 (avg. 4.4)
516 (71.3%)
9 (1.2%)
Series Series
1,085
3,293 (avg. 3.0)
887 (81.8%)
11 (1.0%)
Square Root Square Root
641
1,929 (avg. 3.0)
506 (78.9%)
9 (1.4%)
Word Count Word Count
2,980
17,348 (avg. 5.8)
2,265 (76.0%)
213 (7.1%)
State Of Tic Tac Toe State Of Tic Tac Toe
384
2,602 (avg. 6.8)
230 (59.9%)
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
2,942 (avg. 5.1)
390 (68.1%)
2 (0.3%)
Alphametics Alphametics
611
2,660 (avg. 4.4)
251 (41.1%)
3 (0.5%)
Baffling Birthdays Baffling Birthdays
95
425 (avg. 4.5)
57 (60.0%)
0 (0.0%)
Bank Account Bank Account
1,759
9,617 (avg. 5.5)
1,205 (68.5%)
96 (5.5%)
Binary Search Binary Search
1,422
7,844 (avg. 5.5)
1,071 (75.3%)
94 (6.6%)
Bottle Song Bottle Song
871
7,752 (avg. 8.9)
549 (63.0%)
19 (2.2%)
Bowling Bowling
1,026
8,287 (avg. 8.1)
442 (43.1%)
11 (1.1%)
Camicia Camicia
47
354 (avg. 7.5)
27 (57.4%)
0 (0.0%)
ETL ETL
1,878
2,958 (avg. 1.6)
1,690 (90.0%)
128 (6.8%)
Flower Field Flower Field
119
494 (avg. 4.2)
81 (68.1%)
0 (0.0%)
Food Chain Food Chain
938
3,563 (avg. 3.8)
629 (67.1%)
11 (1.2%)
Grade School Grade School
908
3,133 (avg. 3.5)
650 (71.6%)
22 (2.4%)
House House
1,006
3,766 (avg. 3.7)
720 (71.6%)
10 (1.0%)
Intergalactic Transmission Intergalactic Transmission
984
1,903 (avg. 1.9)
108 (11.0%)
5 (0.5%)
Linked List Linked List
1,475
6,380 (avg. 4.3)
1,040 (70.5%)
78 (5.3%)
Parallel Letter Frequency Parallel Letter Frequency
800
3,712 (avg. 4.6)
494 (61.8%)
13 (1.6%)
Piecing It Together Piecing It Together
84
763 (avg. 9.1)
44 (52.4%)
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
403
1,568 (avg. 3.9)
243 (60.3%)
1 (0.2%)
REST API REST API
803
4,452 (avg. 5.5)
203 (25.3%)
5 (0.6%)
Robot Simulator Robot Simulator
868
2,772 (avg. 3.2)
548 (63.1%)
10 (1.2%)
Roman Numerals Roman Numerals
1,229
3,794 (avg. 3.1)
896 (72.9%)
15 (1.2%)
Spiral Matrix Spiral Matrix
637
1,618 (avg. 2.5)
400 (62.8%)
6 (0.9%)
Tournament Tournament
799
4,024 (avg. 5.0)
406 (50.8%)
10 (1.3%)
Transpose Transpose
582
3,027 (avg. 5.2)
319 (54.8%)
2 (0.3%)
Wordy Wordy
611
2,845 (avg. 4.7)
359 (58.8%)
6 (1.0%)
Anagram Anagram
3,209
10,564 (avg. 3.3)
2,308 (71.9%)
114 (3.6%)
Binary Search Tree Binary Search Tree
695
2,987 (avg. 4.3)
390 (56.1%)
9 (1.3%)
Clock Clock
584
2,467 (avg. 4.2)
388 (66.4%)
3 (0.5%)
Crypto Square Crypto Square
472
1,922 (avg. 4.1)
318 (67.4%)
3 (0.6%)
Dominoes Dominoes
1,100
3,218 (avg. 2.9)
293 (26.6%)
9 (0.8%)
Go Counting Go Counting
515
1,503 (avg. 2.9)
191 (37.1%)
0 (0.0%)
Markdown Markdown
958
2,243 (avg. 2.3)
397 (41.4%)
14 (1.5%)
Meetup Meetup
917
2,450 (avg. 2.7)
710 (77.4%)
13 (1.4%)
Poker Poker
783
2,706 (avg. 3.5)
238 (30.4%)
6 (0.8%)
SGF Parsing SGF Parsing
157
1,948 (avg. 12.4)
88 (56.1%)
2 (1.3%)
Simple Linked List Simple Linked List
791
4,076 (avg. 5.2)
472 (59.7%)
10 (1.3%)
Sublist Sublist
520
1,846 (avg. 3.6)
332 (63.8%)
0 (0.0%)
Tree Building Tree Building
352
846 (avg. 2.4)
161 (45.7%)
3 (0.9%)
Two Bucket Two Bucket
410
1,187 (avg. 2.9)
181 (44.1%)
3 (0.7%)
Word Search Word Search
899
2,608 (avg. 2.9)
286 (31.8%)
5 (0.6%)
Zebra Puzzle Zebra Puzzle
3,239
2,927 (avg. 0.9)
532 (16.4%)
13 (0.4%)
Zipper Zipper
334
973 (avg. 2.9)
148 (44.3%)
0 (0.0%)
Book Store Book Store
680
2,343 (avg. 3.4)
238 (35.0%)
6 (0.9%)
Change Change
581
3,407 (avg. 5.9)
243 (41.8%)
4 (0.7%)
Circular Buffer Circular Buffer
619
2,460 (avg. 4.0)
378 (61.1%)
5 (0.8%)
Complex Numbers Complex Numbers
670
2,318 (avg. 3.5)
418 (62.4%)
11 (1.6%)
Connect Connect
360
1,806 (avg. 5.0)
188 (52.2%)
7 (1.9%)
Hangman Hangman
381
1,130 (avg. 3.0)
102 (26.8%)
6 (1.6%)
List Ops List Ops
569
2,380 (avg. 4.2)
305 (53.6%)
10 (1.8%)
Mazy Mice Mazy Mice
158
718 (avg. 4.5)
72 (45.6%)
4 (2.5%)
OCR Numbers OCR Numbers
395
842 (avg. 2.1)
211 (53.4%)
3 (0.8%)
Palindrome Products Palindrome Products
485
1,492 (avg. 3.1)
258 (53.2%)
5 (1.0%)
POV POV
173
781 (avg. 4.5)
83 (48.0%)
1 (0.6%)
Rational Numbers Rational Numbers
531
3,396 (avg. 6.4)
285 (53.7%)
6 (1.1%)
React React
282
1,140 (avg. 4.0)
91 (32.3%)
2 (0.7%)
Rectangles Rectangles
376
898 (avg. 2.4)
190 (50.5%)
4 (1.1%)
Simple Cipher Simple Cipher
539
1,820 (avg. 3.4)
349 (64.7%)
7 (1.3%)
Forth Forth
531
1,891 (avg. 3.6)
217 (40.9%)
13 (2.4%)
Pythagorean Triplet Pythagorean Triplet
1,090
6,725 (avg. 6.2)
474 (43.5%)
7 (0.6%)
Custom Set Custom Set
606
2,130 (avg. 3.5)
273 (45.0%)
5 (0.8%)
Satellite Satellite
537
1,143 (avg. 2.1)
182 (33.9%)
4 (0.7%)
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: 3f0677266bdae1fa5828cde474d4d65e57f4d967 (Takes up to 10 mins to deploy)

Total Test Runner Runs
4,867,752
Test Run Pass Rate
17.3% (841623)
Test Run Fail Rate
38.1% (1855840)
Test Run Error Rate
44.6% (2170289)

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: 0dacac5bc7ce92d4a2612ffa8eb4c7eac24d3219 (Takes up to 10 mins to deploy)

Total Representer Runs
957,905
Total Representation Comments Made
112,199
Feedback Given Frequency
11.7%

Analyzer

Learn More

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

Current version: 1a09c2c7f5539c77344519ba8a7b6561ad51adde (Takes up to 10 mins to deploy)

Total Analyzer Runs
673,170
Total Analysis Comments Made
436,098
Feedback Given Frequency
4.3%