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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
280,464
Submissions
4,817,155
Mentoring Discussions
17,651

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
60,787 learnt
Bo
Booleans
35,218 learnt
Ar
Arrays
18,096 learnt
Fo
For Loops
18,096 learnt
Fo
For-Each Loops
18,096 learnt
Ge
Generic Types
13,085 learnt
Li
Lists
13,085 learnt
Ex
Exceptions
6,728 learnt
Ch
Chars
11,580 learnt
Cl
Classes
12,336 learnt
Co
Constructors
9,032 learnt
In
Interfaces
6,692 learnt
If
If-Else Statements
18,398 learnt
Nu
Numbers
18,398 learnt
St
Strings
23,283 learnt
Te
Ternary Operators
10,823 learnt
Sw
Switch Statements
7,831 learnt
In
Inheritance
7,057 learnt
En
Enums
4,195 learnt
Nu
Nullability
7,453 learnt
Ra
Randomness
4,865 learnt
Da
Date-Time
5,033 learnt
Me
Method Overloading
3,495 learnt
Bi
Bit Manipulation
4,463 learnt
Se
Sets
3,395 learnt
Ma
Maps
2,508 learnt
22 active learning exercises
Started
Attempts
Completions
Mentoring requests
Cook Your Lasagna Cook Your Lasagna
100,435
548,983 (avg. 5.5)
60,787 (60.5%)
493 (0.5%)
Annalyn's Infiltration Annalyn's Infiltration
47,373
439,741 (avg. 9.3)
35,218 (74.3%)
314 (0.7%)
Bird Watcher Bird Watcher
22,062
299,416 (avg. 13.6)
18,096 (82.0%)
465 (2.1%)
Karl's Languages Karl's Languages
14,604
82,602 (avg. 5.7)
13,085 (89.6%)
113 (0.8%)
Calculator Conundrum Calculator Conundrum
8,266
109,654 (avg. 13.3)
6,728 (81.4%)
112 (1.4%)
Squeaky Clean Squeaky Clean
17,223
251,452 (avg. 14.6)
11,580 (67.2%)
492 (2.9%)
Jedlik's Toy Car Jedlik's Toy Car
13,530
116,734 (avg. 8.6)
12,336 (91.2%)
150 (1.1%)
Need for Speed Need for Speed
10,359
128,597 (avg. 12.4)
9,032 (87.2%)
77 (0.7%)
Remote Control Competition Remote Control Competition
8,420
89,081 (avg. 10.6)
6,692 (79.5%)
100 (1.2%)
Cars, Assemble! Cars, Assemble!
20,506
151,930 (avg. 7.4)
18,398 (89.7%)
411 (2.0%)
Log Levels Log Levels
35,604
316,378 (avg. 8.9)
23,283 (65.4%)
301 (0.8%)
Salary Calculator Salary Calculator
11,664
68,677 (avg. 5.9)
10,823 (92.8%)
41 (0.4%)
Football Match Reports Football Match Reports
8,121
33,607 (avg. 4.1)
7,831 (96.4%)
55 (0.7%)
Wizards and Warriors Wizards and Warriors
7,753
56,767 (avg. 7.3)
7,057 (91.0%)
38 (0.5%)
Logs, Logs, Logs! Logs, Logs, Logs!
4,910
49,647 (avg. 10.1)
4,195 (85.4%)
59 (1.2%)
Tim from Marketing Tim from Marketing
7,897
52,138 (avg. 6.6)
7,453 (94.4%)
65 (0.8%)
Captain's Log Captain's Log
5,183
32,208 (avg. 6.2)
4,865 (93.9%)
21 (0.4%)
Booking Up For Beauty Booking Up For Beauty
6,097
80,895 (avg. 13.3)
5,033 (82.5%)
50 (0.8%)
Wizards and Warriors 2 Wizards and Warriors 2
3,850
33,507 (avg. 8.7)
3,495 (90.8%)
20 (0.5%)
Secrets Secrets
5,134
27,727 (avg. 5.4)
4,463 (86.9%)
7 (0.1%)
Gotta Snatch 'Em All Gotta Snatch 'Em All
3,959
47,307 (avg. 11.9)
3,395 (85.8%)
55 (1.4%)
International Calling Connoisseur International Calling Connoisseur
2,930
31,585 (avg. 10.8)
2,508 (85.6%)
27 (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: f1b22a3dc048451303f910fa08b279dea38e189a (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
219,855
445,732 (avg. 2.0)
134,993 (61.4%)
40 (0.0%)
Leap Leap
8,421
31,830 (avg. 3.8)
6,826 (81.1%)
117 (1.4%)
Reverse String Reverse String
16,104
48,501 (avg. 3.0)
13,460 (83.6%)
330 (2.0%)
Two Fer Two Fer
24,273
77,837 (avg. 3.2)
19,345 (79.7%)
3,926 (16.2%)
Armstrong Numbers Armstrong Numbers
7,591
26,819 (avg. 3.5)
6,090 (80.2%)
148 (1.9%)
Darts Darts
7,571
26,377 (avg. 3.5)
5,991 (79.1%)
66 (0.9%)
D&D Character D&D Character
5,104
42,448 (avg. 8.3)
3,614 (70.8%)
75 (1.5%)
DOT DSL DOT DSL
1,657
7,513 (avg. 4.5)
1,026 (61.9%)
8 (0.5%)
Grains Grains
5,089
39,844 (avg. 7.8)
4,129 (81.1%)
55 (1.1%)
High Scores High Scores
2,856
22,575 (avg. 7.9)
2,288 (80.1%)
38 (1.3%)
Resistor Color Resistor Color
6,824
25,724 (avg. 3.8)
5,527 (81.0%)
74 (1.1%)
Resistor Color Duo Resistor Color Duo
4,844
15,981 (avg. 3.3)
4,112 (84.9%)
46 (0.9%)
Resistor Color Trio Resistor Color Trio
1,833
20,446 (avg. 11.2)
1,559 (85.1%)
40 (2.2%)
RNA Transcription RNA Transcription
6,904
18,226 (avg. 2.6)
5,843 (84.6%)
241 (3.5%)
Acronym Acronym
4,855
21,210 (avg. 4.4)
3,898 (80.3%)
98 (2.0%)
Difference of Squares Difference of Squares
7,159
24,252 (avg. 3.4)
6,275 (87.7%)
710 (9.9%)
Gigasecond Gigasecond
8,749
20,870 (avg. 2.4)
6,313 (72.2%)
1,344 (15.4%)
Hamming Hamming
8,762
33,015 (avg. 3.8)
7,233 (82.5%)
1,495 (17.1%)
Micro Blog Micro Blog
6,943
38,995 (avg. 5.6)
4,285 (61.7%)
103 (1.5%)
Pangram Pangram
5,710
15,470 (avg. 2.7)
4,767 (83.5%)
172 (3.0%)
Perfect Numbers Perfect Numbers
3,745
14,381 (avg. 3.8)
2,658 (71.0%)
53 (1.4%)
Eliud's Eggs Eliud's Eggs
1,374
4,433 (avg. 3.2)
1,231 (89.6%)
17 (1.2%)
Protein Translation Protein Translation
3,854
19,958 (avg. 5.2)
3,037 (78.8%)
61 (1.6%)
Raindrops Raindrops
8,458
22,397 (avg. 2.6)
7,150 (84.5%)
258 (3.1%)
Say Say
2,889
19,400 (avg. 6.7)
1,321 (45.7%)
41 (1.4%)
Scrabble Score Scrabble Score
6,420
23,408 (avg. 3.6)
5,425 (84.5%)
1,085 (16.9%)
Secret Handshake Secret Handshake
4,349
21,758 (avg. 5.0)
3,345 (76.9%)
467 (10.7%)
Space Age Space Age
4,706
10,920 (avg. 2.3)
3,636 (77.3%)
65 (1.4%)
Collatz Conjecture Collatz Conjecture
2,355
9,367 (avg. 4.0)
1,942 (82.5%)
38 (1.6%)
Diamond Diamond
2,982
15,990 (avg. 5.4)
1,973 (66.2%)
57 (1.9%)
Error Handling Error Handling
2,071
14,796 (avg. 7.1)
1,202 (58.0%)
7 (0.3%)
ISBN Verifier ISBN Verifier
2,885
14,016 (avg. 4.9)
2,272 (78.8%)
44 (1.5%)
Isogram Isogram
5,317
20,326 (avg. 3.8)
4,310 (81.1%)
172 (3.2%)
Killer Sudoku Helper Killer Sudoku Helper
893
4,627 (avg. 5.2)
486 (54.4%)
17 (1.9%)
Kindergarten Garden Kindergarten Garden
1,424
4,995 (avg. 3.5)
1,058 (74.3%)
13 (0.9%)
Largest Series Product Largest Series Product
2,088
12,888 (avg. 6.2)
1,651 (79.1%)
23 (1.1%)
Luhn Luhn
2,771
13,801 (avg. 5.0)
2,160 (78.0%)
51 (1.8%)
Matrix Matrix
3,432
17,775 (avg. 5.2)
2,580 (75.2%)
314 (9.1%)
Nth Prime Nth Prime
1,612
6,246 (avg. 3.9)
1,256 (77.9%)
21 (1.3%)
Prism Prism
132
975 (avg. 7.4)
59 (44.7%)
0 (0.0%)
Proverb Proverb
2,978
8,826 (avg. 3.0)
2,416 (81.1%)
34 (1.1%)
Rate Limiter Rate Limiter
290
1,286 (avg. 4.4)
155 (53.4%)
4 (1.4%)
Rotational Cipher Rotational Cipher
2,584
12,955 (avg. 5.0)
2,168 (83.9%)
226 (8.7%)
Saddle Points Saddle Points
1,946
8,886 (avg. 4.6)
1,331 (68.4%)
161 (8.3%)
Sieve Sieve
1,593
4,625 (avg. 2.9)
1,266 (79.5%)
25 (1.6%)
Split-Second Stopwatch Split-Second Stopwatch
221
1,851 (avg. 8.4)
143 (64.7%)
0 (0.0%)
Sum of Multiples Sum of Multiples
2,197
7,987 (avg. 3.6)
1,616 (73.6%)
38 (1.7%)
Swift Scheduling Swift Scheduling
199
1,899 (avg. 9.5)
134 (67.3%)
1 (0.5%)
Triangle Triangle
3,041
12,302 (avg. 4.0)
2,581 (84.9%)
262 (8.6%)
Twelve Days Twelve Days
2,831
15,603 (avg. 5.5)
2,128 (75.2%)
33 (1.2%)
Variable Length Quantity Variable Length Quantity
760
3,059 (avg. 4.0)
400 (52.6%)
2 (0.3%)
Yacht Yacht
1,685
8,211 (avg. 4.9)
1,120 (66.5%)
31 (1.8%)
Allergies Allergies
1,438
5,106 (avg. 3.6)
1,084 (75.4%)
25 (1.7%)
Atbash Cipher Atbash Cipher
905
5,062 (avg. 5.6)
719 (79.4%)
8 (0.9%)
Bob Bob
2,269
13,843 (avg. 6.1)
1,839 (81.0%)
61 (2.7%)
Flatten Array Flatten Array
1,861
8,308 (avg. 4.5)
1,392 (74.8%)
137 (7.4%)
Conway's Game of Life Conway's Game of Life
494
2,327 (avg. 4.7)
310 (62.8%)
1 (0.2%)
Grep Grep
780
3,963 (avg. 5.1)
429 (55.0%)
7 (0.9%)
Knapsack Knapsack
1,023
4,754 (avg. 4.6)
607 (59.3%)
10 (1.0%)
Ledger Ledger
454
3,222 (avg. 7.1)
251 (55.3%)
9 (2.0%)
Matching Brackets Matching Brackets
905
3,450 (avg. 3.8)
649 (71.7%)
10 (1.1%)
Nucleotide Count Nucleotide Count
2,230
6,641 (avg. 3.0)
1,980 (88.8%)
91 (4.1%)
Pascal's Triangle Pascal's Triangle
889
2,450 (avg. 2.8)
633 (71.2%)
5 (0.6%)
Phone Number Phone Number
1,615
9,395 (avg. 5.8)
1,227 (76.0%)
26 (1.6%)
Pig Latin Pig Latin
2,771
12,257 (avg. 4.4)
1,550 (55.9%)
76 (2.7%)
Prime Factors Prime Factors
959
2,920 (avg. 3.0)
734 (76.5%)
11 (1.1%)
Relative Distance Relative Distance
903
5,460 (avg. 6.0)
384 (42.5%)
7 (0.8%)
Robot Name Robot Name
1,903
10,730 (avg. 5.6)
1,556 (81.8%)
138 (7.3%)
Run-Length Encoding Run-Length Encoding
719
3,120 (avg. 4.3)
512 (71.2%)
9 (1.3%)
Series Series
1,078
3,256 (avg. 3.0)
880 (81.6%)
11 (1.0%)
Square Root Square Root
630
1,906 (avg. 3.0)
497 (78.9%)
9 (1.4%)
Word Count Word Count
2,953
17,188 (avg. 5.8)
2,250 (76.2%)
212 (7.2%)
State Of Tic Tac Toe State Of Tic Tac Toe
372
2,507 (avg. 6.7)
225 (60.5%)
6 (1.6%)
Affine Cipher Affine Cipher
422
3,116 (avg. 7.4)
275 (65.2%)
4 (0.9%)
All Your Base All Your Base
568
2,900 (avg. 5.1)
385 (67.8%)
2 (0.4%)
Alphametics Alphametics
606
2,627 (avg. 4.3)
247 (40.8%)
3 (0.5%)
Baffling Birthdays Baffling Birthdays
86
404 (avg. 4.7)
49 (57.0%)
0 (0.0%)
Bank Account Bank Account
1,737
9,440 (avg. 5.4)
1,195 (68.8%)
93 (5.4%)
Binary Search Binary Search
1,405
7,761 (avg. 5.5)
1,059 (75.4%)
93 (6.6%)
Bottle Song Bottle Song
850
7,616 (avg. 9.0)
537 (63.2%)
19 (2.2%)
Bowling Bowling
1,010
8,254 (avg. 8.2)
435 (43.1%)
11 (1.1%)
Camicia Camicia
37
339 (avg. 9.2)
21 (56.8%)
0 (0.0%)
ETL ETL
1,865
2,890 (avg. 1.5)
1,679 (90.0%)
128 (6.9%)
Flower Field Flower Field
112
467 (avg. 4.2)
75 (67.0%)
0 (0.0%)
Food Chain Food Chain
928
3,528 (avg. 3.8)
621 (66.9%)
11 (1.2%)
Grade School Grade School
888
3,021 (avg. 3.4)
638 (71.8%)
22 (2.5%)
House House
1,001
3,751 (avg. 3.7)
716 (71.5%)
10 (1.0%)
Intergalactic Transmission Intergalactic Transmission
864
1,811 (avg. 2.1)
98 (11.3%)
5 (0.6%)
Linked List Linked List
1,458
6,325 (avg. 4.3)
1,030 (70.6%)
78 (5.3%)
Parallel Letter Frequency Parallel Letter Frequency
795
3,669 (avg. 4.6)
490 (61.6%)
13 (1.6%)
Piecing It Together Piecing It Together
80
759 (avg. 9.5)
41 (51.2%)
0 (0.0%)
Queen Attack Queen Attack
2,072
7,868 (avg. 3.8)
775 (37.4%)
34 (1.6%)
Rail Fence Cipher Rail Fence Cipher
397
1,528 (avg. 3.8)
238 (59.9%)
1 (0.3%)
REST API REST API
788
4,366 (avg. 5.5)
196 (24.9%)
5 (0.6%)
Robot Simulator Robot Simulator
855
2,731 (avg. 3.2)
540 (63.2%)
10 (1.2%)
Roman Numerals Roman Numerals
1,220
3,745 (avg. 3.1)
891 (73.0%)
15 (1.2%)
Spiral Matrix Spiral Matrix
631
1,577 (avg. 2.5)
395 (62.6%)
6 (1.0%)
Tournament Tournament
774
3,723 (avg. 4.8)
395 (51.0%)
10 (1.3%)
Transpose Transpose
578
2,950 (avg. 5.1)
316 (54.7%)
2 (0.3%)
Wordy Wordy
606
2,764 (avg. 4.6)
357 (58.9%)
6 (1.0%)
Anagram Anagram
3,188
10,404 (avg. 3.3)
2,290 (71.8%)
113 (3.5%)
Binary Search Tree Binary Search Tree
683
2,844 (avg. 4.2)
385 (56.4%)
9 (1.3%)
Clock Clock
573
2,390 (avg. 4.2)
386 (67.4%)
3 (0.5%)
Crypto Square Crypto Square
468
1,869 (avg. 4.0)
315 (67.3%)
3 (0.6%)
Dominoes Dominoes
1,097
3,191 (avg. 2.9)
292 (26.6%)
9 (0.8%)
Go Counting Go Counting
511
1,501 (avg. 2.9)
190 (37.2%)
0 (0.0%)
Markdown Markdown
948
2,237 (avg. 2.4)
392 (41.4%)
14 (1.5%)
Meetup Meetup
914
2,443 (avg. 2.7)
707 (77.4%)
13 (1.4%)
Poker Poker
773
2,682 (avg. 3.5)
236 (30.5%)
4 (0.5%)
SGF Parsing SGF Parsing
156
1,946 (avg. 12.5)
86 (55.1%)
2 (1.3%)
Simple Linked List Simple Linked List
780
3,931 (avg. 5.0)
468 (60.0%)
10 (1.3%)
Sublist Sublist
517
1,840 (avg. 3.6)
330 (63.8%)
0 (0.0%)
Tree Building Tree Building
349
844 (avg. 2.4)
160 (45.8%)
3 (0.9%)
Two Bucket Two Bucket
407
1,185 (avg. 2.9)
180 (44.2%)
3 (0.7%)
Word Search Word Search
894
2,554 (avg. 2.9)
283 (31.7%)
5 (0.6%)
Zebra Puzzle Zebra Puzzle
3,153
2,837 (avg. 0.9)
516 (16.4%)
12 (0.4%)
Zipper Zipper
331
966 (avg. 2.9)
146 (44.1%)
0 (0.0%)
Book Store Book Store
669
2,317 (avg. 3.5)
232 (34.7%)
6 (0.9%)
Change Change
573
3,310 (avg. 5.8)
240 (41.9%)
4 (0.7%)
Circular Buffer Circular Buffer
614
2,407 (avg. 3.9)
373 (60.7%)
5 (0.8%)
Complex Numbers Complex Numbers
661
2,294 (avg. 3.5)
413 (62.5%)
11 (1.7%)
Connect Connect
359
1,804 (avg. 5.0)
187 (52.1%)
7 (1.9%)
Hangman Hangman
376
1,125 (avg. 3.0)
100 (26.6%)
6 (1.6%)
List Ops List Ops
554
2,333 (avg. 4.2)
299 (54.0%)
9 (1.6%)
Mazy Mice Mazy Mice
151
714 (avg. 4.7)
69 (45.7%)
4 (2.6%)
OCR Numbers OCR Numbers
393
840 (avg. 2.1)
210 (53.4%)
3 (0.8%)
Palindrome Products Palindrome Products
483
1,464 (avg. 3.0)
256 (53.0%)
5 (1.0%)
POV POV
167
778 (avg. 4.7)
81 (48.5%)
1 (0.6%)
Rational Numbers Rational Numbers
523
3,295 (avg. 6.3)
282 (53.9%)
6 (1.1%)
React React
268
1,133 (avg. 4.2)
88 (32.8%)
2 (0.7%)
Rectangles Rectangles
373
885 (avg. 2.4)
187 (50.1%)
4 (1.1%)
Simple Cipher Simple Cipher
533
1,770 (avg. 3.3)
346 (64.9%)
7 (1.3%)
Forth Forth
528
1,844 (avg. 3.5)
216 (40.9%)
13 (2.5%)
Pythagorean Triplet Pythagorean Triplet
1,085
6,716 (avg. 6.2)
471 (43.4%)
7 (0.6%)
Custom Set Custom Set
593
2,096 (avg. 3.5)
268 (45.2%)
5 (0.8%)
Satellite Satellite
528
1,107 (avg. 2.1)
179 (33.9%)
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: 44a68063e869cb6dd02d0376339e93e091fff24c (Takes up to 10 mins to deploy)

Total Test Runner Runs
4,731,353
Test Run Pass Rate
17.3% (816795)
Test Run Fail Rate
38.2% (1805381)
Test Run Error Rate
44.6% (2109177)

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: b75c4c178279a25f758787d7d26c07b23d227cb9 (Takes up to 10 mins to deploy)

Total Representer Runs
935,279
Total Representation Comments Made
106,551
Feedback Given Frequency
11.4%

Analyzer

Learn More

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

Current version: bafd318a97593f8bb3c950be87903b4d13cad3e1 (Takes up to 10 mins to deploy)

Total Analyzer Runs
650,566
Total Analysis Comments Made
418,620
Feedback Given Frequency
4.2%