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Java
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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
202,332
Submissions
3,118,470
Mentoring Discussions
16,150

The Java track needs attention ⚠️

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.
25 concepts being taught
Ba
Basics
40,329 learnt
Bo
Booleans
22,760 learnt
Ar
Arrays
10,474 learnt
Fo
For Loops
10,474 learnt
Fo
For-Each Loops
10,474 learnt
Ge
Generic Types
7,351 learnt
Li
Lists
7,351 learnt
Ex
Exceptions
2,913 learnt
Ch
Chars
7,114 learnt
Cl
Classes
6,836 learnt
Co
Constructors
5,054 learnt
In
Interfaces
3,746 learnt
If
If-Else Statements
10,972 learnt
Nu
Numbers
10,972 learnt
St
Strings
15,478 learnt
Te
Ternary Operators
6,082 learnt
Sw
Switch Statements
4,419 learnt
In
Inheritance
3,978 learnt
En
Enums
1,876 learnt
Nu
Nullability
3,018 learnt
Ra
Randomness
2,028 learnt
Da
Date-Time
2,066 learnt
Me
Method Overloading
1,535 learnt
Bi
Bit Manipulation
1,795 learnt
Se
Sets
1,268 learnt
21 active learning exercises
Started
Attempts
Completions
Mentoring requests
Cook Your Lasagna Cook Your Lasagna
65,688
359,809 (avg. 5.5)
40,329 (61.4%)
462 (0.7%)
Annalyn's Infiltration Annalyn's Infiltration
30,439
287,427 (avg. 9.4)
22,760 (74.8%)
301 (1.0%)
Bird Watcher Bird Watcher
12,504
172,062 (avg. 13.8)
10,474 (83.8%)
236 (1.9%)
Karl's Languages Karl's Languages
8,009
43,744 (avg. 5.5)
7,351 (91.8%)
63 (0.8%)
Calculator Conundrum Calculator Conundrum
3,544
49,714 (avg. 14.0)
2,913 (82.2%)
56 (1.6%)
Squeaky Clean Squeaky Clean
11,445
177,456 (avg. 15.5)
7,114 (62.2%)
344 (3.0%)
Elon's Toy Car Elon's Toy Car
7,381
61,773 (avg. 8.4)
6,836 (92.6%)
80 (1.1%)
Need for Speed Need for Speed
5,709
66,400 (avg. 11.6)
5,054 (88.5%)
61 (1.1%)
Remote Control Competition Remote Control Competition
4,743
51,759 (avg. 10.9)
3,746 (79.0%)
75 (1.6%)
Cars, Assemble! Cars, Assemble!
12,210
93,131 (avg. 7.6)
10,972 (89.9%)
222 (1.8%)
Log Levels Log Levels
24,222
219,131 (avg. 9.0)
15,478 (63.9%)
273 (1.1%)
Salary Calculator Salary Calculator
6,537
37,874 (avg. 5.8)
6,082 (93.0%)
38 (0.6%)
Football Match Reports Football Match Reports
4,560
19,069 (avg. 4.2)
4,419 (96.9%)
35 (0.8%)
Wizards and Warriors Wizards and Warriors
4,313
29,236 (avg. 6.8)
3,978 (92.2%)
32 (0.7%)
Logs, Logs, Logs! Logs, Logs, Logs!
2,207
22,730 (avg. 10.3)
1,876 (85.0%)
31 (1.4%)
Tim from Marketing Tim from Marketing
3,219
22,031 (avg. 6.8)
3,018 (93.8%)
47 (1.5%)
Captain's Log Captain's Log
2,168
14,291 (avg. 6.6)
2,028 (93.5%)
13 (0.6%)
Booking Up For Beauty Booking Up For Beauty
2,499
36,497 (avg. 14.6)
2,066 (82.7%)
19 (0.8%)
Wizards and Warriors 2 Wizards and Warriors 2
1,686
14,677 (avg. 8.7)
1,535 (91.0%)
16 (0.9%)
Secrets Secrets
2,071
11,989 (avg. 5.8)
1,795 (86.7%)
4 (0.2%)
Gotta Snatch 'Em All Gotta Snatch 'Em All
1,529
19,648 (avg. 12.9)
1,268 (82.9%)
24 (1.6%)
1 deprecated learning exercises
Started
Attempts
Completions
Mentoring requests
Play Your Cards! Play Your Cards!
8,676
85,863 (avg. 9.9)
6,851 (79.0%)
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: 89fb0774c7a8d182ad62a6db06d76790afab34cd (Updates should be instant)

Next goal: Implement 128 practice exercises. Find out more.
127 active practice exercises
Started
Attempts
Completions
Mentoring requests
Hello World Hello World
146,814
303,813 (avg. 2.1)
93,970 (64.0%)
40 (0.0%)
Leap Leap
5,407
17,285 (avg. 3.2)
4,385 (81.1%)
84 (1.6%)
Reverse String Reverse String
13,760
40,269 (avg. 2.9)
11,463 (83.3%)
313 (2.3%)
Two Fer Two Fer
22,078
69,632 (avg. 3.2)
17,389 (78.8%)
3,917 (17.7%)
Armstrong Numbers Armstrong Numbers
5,471
15,767 (avg. 2.9)
4,250 (77.7%)
125 (2.3%)
Darts Darts
5,625
18,902 (avg. 3.4)
4,368 (77.7%)
59 (1.0%)
D&D Character D&D Character
3,710
26,968 (avg. 7.3)
2,569 (69.2%)
58 (1.6%)
DOT DSL DOT DSL
426
2,139 (avg. 5.0)
258 (60.6%)
4 (0.9%)
Grains Grains
3,601
26,783 (avg. 7.4)
2,896 (80.4%)
45 (1.2%)
High Scores High Scores
1,491
12,914 (avg. 8.7)
1,210 (81.2%)
29 (1.9%)
Resistor Color Resistor Color
5,580
19,196 (avg. 3.4)
4,404 (78.9%)
67 (1.2%)
Resistor Color Duo Resistor Color Duo
3,785
11,564 (avg. 3.1)
3,150 (83.2%)
39 (1.0%)
Resistor Color Trio Resistor Color Trio
834
10,207 (avg. 12.2)
701 (84.1%)
22 (2.6%)
RNA Transcription RNA Transcription
5,883
14,243 (avg. 2.4)
4,932 (83.8%)
228 (3.9%)
Acronym Acronym
3,802
14,198 (avg. 3.7)
2,996 (78.8%)
86 (2.3%)
Difference of Squares Difference of Squares
6,121
20,532 (avg. 3.4)
5,324 (87.0%)
705 (11.5%)
Gigasecond Gigasecond
7,971
18,528 (avg. 2.3)
5,644 (70.8%)
1,343 (16.8%)
Hamming Hamming
7,847
28,343 (avg. 3.6)
6,444 (82.1%)
1,488 (19.0%)
Micro Blog Micro Blog
5,802
33,399 (avg. 5.8)
3,481 (60.0%)
83 (1.4%)
Pangram Pangram
4,796
11,322 (avg. 2.4)
3,961 (82.6%)
165 (3.4%)
Perfect Numbers Perfect Numbers
3,048
10,954 (avg. 3.6)
2,038 (66.9%)
41 (1.3%)
Eliud's Eggs Eliud's Eggs
670
2,296 (avg. 3.4)
597 (89.1%)
7 (1.0%)
Protein Translation Protein Translation
3,092
12,640 (avg. 4.1)
2,431 (78.6%)
45 (1.5%)
Raindrops Raindrops
7,568
19,417 (avg. 2.6)
6,338 (83.7%)
248 (3.3%)
Say Say
2,072
12,154 (avg. 5.9)
803 (38.8%)
34 (1.6%)
Scrabble Score Scrabble Score
5,743
20,873 (avg. 3.6)
4,845 (84.4%)
1,080 (18.8%)
Secret Handshake Secret Handshake
3,795
18,157 (avg. 4.8)
2,881 (75.9%)
464 (12.2%)
Space Age Space Age
3,890
7,968 (avg. 2.0)
2,980 (76.6%)
60 (1.5%)
Collatz Conjecture Collatz Conjecture
1,457
5,231 (avg. 3.6)
1,205 (82.7%)
20 (1.4%)
Diamond Diamond
2,245
10,197 (avg. 4.5)
1,480 (65.9%)
44 (2.0%)
Error Handling Error Handling
1,410
10,022 (avg. 7.1)
782 (55.5%)
5 (0.4%)
ISBN Verifier ISBN Verifier
2,275
9,331 (avg. 4.1)
1,769 (77.8%)
39 (1.7%)
Isogram Isogram
4,619
16,756 (avg. 3.6)
3,706 (80.2%)
166 (3.6%)
Killer Sudoku Helper Killer Sudoku Helper
407
2,229 (avg. 5.5)
225 (55.3%)
11 (2.7%)
Kindergarten Garden Kindergarten Garden
988
2,664 (avg. 2.7)
721 (73.0%)
9 (0.9%)
Largest Series Product Largest Series Product
1,623
8,458 (avg. 5.2)
1,291 (79.5%)
19 (1.2%)
Luhn Luhn
2,262
10,113 (avg. 4.5)
1,753 (77.5%)
47 (2.1%)
Matrix Matrix
2,973
14,906 (avg. 5.0)
2,245 (75.5%)
312 (10.5%)
Nth Prime Nth Prime
1,234
4,156 (avg. 3.4)
944 (76.5%)
15 (1.2%)
Proverb Proverb
2,592
7,209 (avg. 2.8)
2,093 (80.7%)
31 (1.2%)
Rotational Cipher Rotational Cipher
2,243
11,086 (avg. 4.9)
1,888 (84.2%)
224 (10.0%)
Saddle Points Saddle Points
1,648
6,987 (avg. 4.2)
1,117 (67.8%)
160 (9.7%)
Sieve Sieve
1,276
3,342 (avg. 2.6)
1,016 (79.6%)
23 (1.8%)
Sum of Multiples Sum of Multiples
1,851
6,143 (avg. 3.3)
1,340 (72.4%)
34 (1.8%)
Triangle Triangle
2,701
10,558 (avg. 3.9)
2,300 (85.2%)
258 (9.6%)
Twelve Days Twelve Days
2,521
13,513 (avg. 5.4)
1,898 (75.3%)
32 (1.3%)
Variable Length Quantity Variable Length Quantity
566
1,749 (avg. 3.1)
283 (50.0%)
1 (0.2%)
Yacht Yacht
1,452
6,322 (avg. 4.4)
951 (65.5%)
28 (1.9%)
Allergies Allergies
1,159
3,782 (avg. 3.3)
896 (77.3%)
25 (2.2%)
Atbash Cipher Atbash Cipher
682
3,327 (avg. 4.9)
536 (78.6%)
7 (1.0%)
Bob Bob
1,922
10,858 (avg. 5.6)
1,570 (81.7%)
57 (3.0%)
Flatten Array Flatten Array
1,569
6,971 (avg. 4.4)
1,180 (75.2%)
134 (8.5%)
Conway's Game of Life Conway's Game of Life
196
804 (avg. 4.1)
105 (53.6%)
0 (0.0%)
Grep Grep
572
2,302 (avg. 4.0)
303 (53.0%)
5 (0.9%)
Knapsack Knapsack
810
3,695 (avg. 4.6)
483 (59.6%)
9 (1.1%)
Ledger Ledger
257
1,725 (avg. 6.7)
137 (53.3%)
6 (2.3%)
Matching Brackets Matching Brackets
662
2,319 (avg. 3.5)
473 (71.5%)
8 (1.2%)
Nucleotide Count Nucleotide Count
2,006
5,649 (avg. 2.8)
1,798 (89.6%)
89 (4.4%)
Pascal's Triangle Pascal's Triangle
696
1,685 (avg. 2.4)
483 (69.4%)
4 (0.6%)
Phone Number Phone Number
1,367
6,873 (avg. 5.0)
1,061 (77.6%)
23 (1.7%)
Pig Latin Pig Latin
2,596
10,641 (avg. 4.1)
1,420 (54.7%)
75 (2.9%)
Prime Factors Prime Factors
780
2,343 (avg. 3.0)
587 (75.3%)
10 (1.3%)
Robot Name Robot Name
1,680
9,474 (avg. 5.6)
1,398 (83.2%)
137 (8.2%)
Run-Length Encoding Run-Length Encoding
560
2,048 (avg. 3.7)
392 (70.0%)
9 (1.6%)
Series Series
900
2,435 (avg. 2.7)
739 (82.1%)
9 (1.0%)
Square Root Square Root
373
1,149 (avg. 3.1)
293 (78.6%)
7 (1.9%)
Word Count Word Count
2,723
15,556 (avg. 5.7)
2,085 (76.6%)
212 (7.8%)
State Of Tic Tac Toe State Of Tic Tac Toe
171
1,112 (avg. 6.5)
100 (58.5%)
5 (2.9%)
Affine Cipher Affine Cipher
294
1,925 (avg. 6.5)
185 (62.9%)
3 (1.0%)
All Your Base All Your Base
427
1,815 (avg. 4.3)
280 (65.6%)
2 (0.5%)
Alphametics Alphametics
476
1,794 (avg. 3.8)
178 (37.4%)
3 (0.6%)
Bank Account Bank Account
1,453
7,954 (avg. 5.5)
1,038 (71.4%)
89 (6.1%)
Binary Search Binary Search
1,194
6,599 (avg. 5.5)
906 (75.9%)
93 (7.8%)
Bottle Song Bottle Song
581
5,666 (avg. 9.8)
371 (63.9%)
18 (3.1%)
Bowling Bowling
828
5,874 (avg. 7.1)
365 (44.1%)
11 (1.3%)
ETL ETL
1,712
2,443 (avg. 1.4)
1,570 (91.7%)
128 (7.5%)
Food Chain Food Chain
798
2,910 (avg. 3.6)
539 (67.5%)
10 (1.3%)
Grade School Grade School
719
2,204 (avg. 3.1)
527 (73.3%)
21 (2.9%)
House House
873
3,199 (avg. 3.7)
638 (73.1%)
9 (1.0%)
Linked List Linked List
1,281
5,421 (avg. 4.2)
924 (72.1%)
75 (5.9%)
Minesweeper Minesweeper
754
2,678 (avg. 3.6)
492 (65.3%)
8 (1.1%)
Parallel Letter Frequency Parallel Letter Frequency
646
2,974 (avg. 4.6)
406 (62.8%)
12 (1.9%)
Queen Attack Queen Attack
1,956
7,304 (avg. 3.7)
698 (35.7%)
33 (1.7%)
Rail Fence Cipher Rail Fence Cipher
304
1,179 (avg. 3.9)
178 (58.6%)
1 (0.3%)
REST API REST API
559
2,356 (avg. 4.2)
129 (23.1%)
4 (0.7%)
Robot Simulator Robot Simulator
712
2,208 (avg. 3.1)
444 (62.4%)
10 (1.4%)
Roman Numerals Roman Numerals
1,066
3,151 (avg. 3.0)
789 (74.0%)
15 (1.4%)
Spiral Matrix Spiral Matrix
515
1,209 (avg. 2.3)
312 (60.6%)
5 (1.0%)
Tournament Tournament
543
2,339 (avg. 4.3)
283 (52.1%)
9 (1.7%)
Transpose Transpose
474
2,185 (avg. 4.6)
251 (53.0%)
2 (0.4%)
Wordy Wordy
501
2,041 (avg. 4.1)
287 (57.3%)
6 (1.2%)
Anagram Anagram
3,041
9,538 (avg. 3.1)
2,184 (71.8%)
111 (3.7%)
Binary Search Tree Binary Search Tree
545
2,095 (avg. 3.8)
306 (56.1%)
7 (1.3%)
Clock Clock
459
1,807 (avg. 3.9)
305 (66.4%)
2 (0.4%)
Crypto Square Crypto Square
383
1,496 (avg. 3.9)
259 (67.6%)
2 (0.5%)
Dominoes Dominoes
1,003
2,843 (avg. 2.8)
243 (24.2%)
9 (0.9%)
Go Counting Go Counting
435
1,126 (avg. 2.6)
146 (33.6%)
0 (0.0%)
Markdown Markdown
819
1,662 (avg. 2.0)
321 (39.2%)
14 (1.7%)
Meetup Meetup
809
1,985 (avg. 2.5)
648 (80.1%)
11 (1.4%)
Poker Poker
667
2,112 (avg. 3.2)
194 (29.1%)
4 (0.6%)
SGF Parsing SGF Parsing
92
1,181 (avg. 12.8)
52 (56.5%)
2 (2.2%)
Simple Linked List Simple Linked List
636
3,156 (avg. 5.0)
387 (60.8%)
8 (1.3%)
Sublist Sublist
396
1,353 (avg. 3.4)
258 (65.2%)
0 (0.0%)
Tree Building Tree Building
258
542 (avg. 2.1)
112 (43.4%)
2 (0.8%)
Two Bucket Two Bucket
316
874 (avg. 2.8)
136 (43.0%)
3 (0.9%)
Word Search Word Search
794
2,181 (avg. 2.7)
236 (29.7%)
5 (0.6%)
Zebra Puzzle Zebra Puzzle
1,706
1,465 (avg. 0.9)
311 (18.2%)
4 (0.2%)
Zipper Zipper
236
646 (avg. 2.7)
102 (43.2%)
0 (0.0%)
Book Store Book Store
450
1,270 (avg. 2.8)
159 (35.3%)
5 (1.1%)
Change Change
434
2,014 (avg. 4.6)
173 (39.9%)
4 (0.9%)
Circular Buffer Circular Buffer
486
1,701 (avg. 3.5)
294 (60.5%)
4 (0.8%)
Complex Numbers Complex Numbers
476
1,515 (avg. 3.2)
294 (61.8%)
11 (2.3%)
Connect Connect
283
1,454 (avg. 5.1)
144 (50.9%)
7 (2.5%)
Hangman Hangman
260
668 (avg. 2.6)
62 (23.8%)
5 (1.9%)
List Ops List Ops
419
1,815 (avg. 4.3)
227 (54.2%)
8 (1.9%)
Mazy Mice Mazy Mice
70
489 (avg. 7.0)
30 (42.9%)
0 (0.0%)
OCR Numbers OCR Numbers
327
640 (avg. 2.0)
168 (51.4%)
3 (0.9%)
Palindrome Products Palindrome Products
385
1,095 (avg. 2.8)
199 (51.7%)
3 (0.8%)
POV POV
89
617 (avg. 6.9)
47 (52.8%)
1 (1.1%)
Rational Numbers Rational Numbers
370
2,124 (avg. 5.7)
203 (54.9%)
4 (1.1%)
React React
132
728 (avg. 5.5)
46 (34.8%)
1 (0.8%)
Rectangles Rectangles
297
775 (avg. 2.6)
145 (48.8%)
3 (1.0%)
Simple Cipher Simple Cipher
450
1,404 (avg. 3.1)
287 (63.8%)
7 (1.6%)
Forth Forth
453
1,484 (avg. 3.3)
179 (39.5%)
11 (2.4%)
Pythagorean Triplet Pythagorean Triplet
960
6,051 (avg. 6.3)
414 (43.1%)
5 (0.5%)
Custom Set Custom Set
436
1,496 (avg. 3.4)
201 (46.1%)
2 (0.5%)
Satellite Satellite
309
763 (avg. 2.5)
121 (39.2%)
2 (0.6%)
8 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
3,372 (avg. 3.9)
662 (76.4%)
15 (1.7%)
Binary Binary
136
180 (avg. 1.3)
133 (97.8%)
6 (4.4%)
Diffie-Hellman Diffie-Hellman
228
327 (avg. 1.4)
117 (51.3%)
2 (0.9%)
Hexadecimal Hexadecimal
58
73 (avg. 1.3)
55 (94.8%)
7 (12.1%)
Octal Octal
59
69 (avg. 1.2)
56 (94.9%)
2 (3.4%)
Strain Strain
111
141 (avg. 1.3)
107 (96.4%)
5 (4.5%)
Trinary Trinary
71
83 (avg. 1.2)
68 (95.8%)
1 (1.4%)
1 unimplemented practice exercise
PaaS I/O PaaS I/O
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

Programming Tags

Learn More

Help manage the tags used to group, filter and recommend solutions, approaches and articles.

0 tags

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: 97dbccf42aed37c28e021defd0cef2a5a58e16c3 (Takes up to 10 mins to deploy)

Total Test Runner Runs
3,044,392
Test Run Pass Rate
17.5% (531582)
Test Run Fail Rate
37.7% (1147284)
Test Run Error Rate
44.9% (1365526)

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: cc24d53bd7f8eb6b6b5607b351a7bb11182b8ea6 (Takes up to 10 mins to deploy)

Total Representer Runs
678,427
Total Representation Comments Made
4
Feedback Given Frequency
0.0%

Analyzer

Learn More

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

Current version: c5706d60d48307cf772f58651a5662dca290fe79 (Takes up to 10 mins to deploy)

Total Analyzer Runs
394,184
Total Analysis Comments Made
218,522
Feedback Given Frequency
3.2%