How java is put together
TheAlgorithms/Java is an educational library of algorithm implementations in Java, organized as a single Maven-built JAR (com.thealgorithms:Java, Java 21) with no application entry point or runtime services. Code is grouped into domain packages under src/main/java/com/thealgorithms/ (e.g., backtracking, bitmanipulation, ciphers, compression, conversions, divideandconquer, dynamicprogramming), each containing self-contained classes with static utility methods or small stateful objects. There is no data flow between components beyond shared JDK collections; the 'architecture' is a flat catalog of independent algorithm classes. Quality is enforced via a heavy static-analysis toolchain wired into the Maven build (Checkstyle, SpotBugs+findsecbugs, PMD with security ruleset, JaCoCo coverage), and tests live under src/test using JUnit 5, AssertJ, and Mockito.
Languages
Frameworks
Infrastructure
Major components
audiofilters
Digital signal processing filters such as exponential moving average (EMAFilter) and N-order IIR filtering over double sample arrays.
backtracking
Backtracking search algorithms including path finding, combinations/permutations, N-Queens, Sudoku solving, maze solving, and word search.
bitmanipulation
Bit-level operations and conversions such as set-bit counting, bit rotation/swapping, Gray code, parity checks, and power-of-two checks.
ciphers
Educational implementations of classical and modern ciphers (Caesar, Vigenere, AES, DES, Blowfish, RSA, DiffieHellman, ECC, ElGamal) for learning purposes.
compression
Lossless compression algorithms including Huffman coding, LZW/LZ77/LZ78, Burrows-Wheeler Transform, arithmetic coding, and run-length encoding.
conversions
Number/base/format conversion utilities such as binary/hex/octal conversions, Base64, IP converters, Roman numerals, Morse code, and unit/temperature converters.
divideandconquer
Divide-and-conquer algorithms like binary exponentiation, closest pair, Strassen matrix multiplication, counting inversions, and skyline computation.
dynamicprogramming
DP solutions covering knapsack variants, longest common/increasing subsequences, edit distances, coin change, matrix chain multiplication, and sequence alignment.
A quiet week with just one automated tooling update.
5 weeksWeek of 2026-08-24
Week of 2026-08-24latest
A quiet week with just one automated tooling update.
Week of 2026-08-17
A new data structure arrived alongside two bug fixes and routine tool updates.
Week of 2026-08-10
Bug fixes took center stage, correcting two subtle data-handling errors, plus several dependency bumps.
Week of 2026-08-03
Three search algorithm bugs were fixed in a single push, along with routine tooling updates.
Week of 2026-08-03
Placeholder — see corrected entry above.
Over the past five weeks, this repository of classic algorithms implemented in Java saw a steady stream of bug fixes, especially around search and data-structure edge cases like integer overflow, off-by-one errors, and infinite loops. New features landed too, including a self-organizing linked list, a concurrent merge sort, a Naive Bayes classifier, and a 'rotting oranges' simulation. The rest of the activity was routine maintenance, mostly automated updates to development tools and testing libraries.
Week by week
2026-08-24A quiet week with just one automated tooling update.latest1 change
Chore
Code style tool updated
The project's automatic code style checker (Checkstyle) was upgraded from version 13.10.0 to 13.11.0.
2026-08-17A new data structure arrived alongside two bug fixes and routine tool updates.4 changes
Feature
Self-organizing list added
Added a SelfOrganizingLinkedList, a list that automatically moves frequently used items toward the front for faster access, complete with tests.
Fix
Mobius function overflow fixed
Fixed an integer overflow bug in the MobiusFunction, a number-theory calculation that could produce wrong results for large inputs.
Chore
Security scanner updated
The CodeQL security analysis workflow was bumped from 4.37.6 to 4.37.7.
Chore
Checkstyle upgraded
The code style checking tool was upgraded from version 13.9.0 to 13.10.0.
2026-08-10Bug fixes took center stage, correcting two subtle data-handling errors, plus several dependency bumps.5 changes
Fix
Segment tree bounds fixed
Fixed an off-by-one error in the SegmentTree's boundary checks that could cause the wrong range of data to be read.
Fix
Rail fence cipher newline fix
Fixed the RailFenceCipher so it no longer silently drops newline characters when encoding text.
Chore
Testing library updated
The JUnit testing framework was upgraded from version 6.1.2 to 6.1.3.
Chore
Security scanner updated
The CodeQL security analysis workflow was bumped twice, ending at version 4.37.6.
Chore
Collections library updated
Apache Commons Collections was upgraded from version 4.5.0 to 4.6.0.
2026-08-03Three search algorithm bugs were fixed in a single push, along with routine tooling updates.5 changes
Fix
Fibonacci search fixed
Fixed out-of-bounds access and incorrect comparisons in FibonacciSearch, a method for finding items in sorted lists.
Fix
Exponential search fixed
Corrected ExponentialSearch so it no longer misses elements at the boundaries and properly returns -1 when an item isn't found.
Fix
Jump search hang fixed
Fixed an infinite loop in JumpSearch that occurred when searching for a value larger than everything in the list.
Chore
Automation tools updated
Updated GitHub Actions components: the stale-issue manager jumped to v11, setup-java moved to 5.7.0, and the CodeQL scanner reached 4.37.4.
Chore
Checkstyle upgraded
The code style checker was upgraded from version 13.8.0 to 13.9.0.
2026-08-03Placeholder — see corrected entry above.0 changes
Dependencies and code review
Dependency advisories
Security Watch
No known advisories across 0 scanned dependencies.
No known advisories in the scanned dependencies.
Code review
No concrete code-level issues confirmed.
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