JavaJava · Bytes catalog

Screen Java candidates on real starter repos

51 short Java tasks, each shipping with a public test file and a language-specific runner. Candidates work in their own style; reviewers see how the code actually hangs together.

Starter
13
Standard
23
Advanced
15
Catalog
51 Java bytes
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Alarm Beacon
Featured
JavaJavaStarter~2h

Alarm Beacon

Your task is to convert a signal code number into a string of beacon alert patterns.

build.gradle
Open byte →
Alarm Chime
JavaJava
Starter~2h
Alarm Chime

Your task is to convert an alert code number into a string of alarm chime sounds.

build.gradle
Archive Code
JavaJava
Standard~3h
Archive Code

The archive code verification process is used to validate catalog identifiers. These usually contain dashes and look.

build.gradle
Base Trail
JavaJava
Standard~3h
Base Trail

Convert a number, represented as a sequence of digits in one base, to another base by following a base trail.

build.gradle
Beacon Board
JavaJava
Advanced~4h
Beacon Board

A maintenance beacon board spells out numbers using a 3 x 4 grid of pipes, underscores, and spaces. Decode the digits,.

build.gradle
Beacon Ring
JavaJava
Starter~2h
Beacon Ring

Track a signal beacon that awards points based on how close a shot lands to the center of a circular target.

build.gradle
Bid Ranker
JavaJava
Advanced~4h
Bid Ranker

Your team is building the ranking engine for an online auction platform. Each bid submitted to an auction carries five.

build.gradle
Billing Cycle
JavaJava
Starter~2h
Billing Cycle

An internal billing system assigns sequential period numbers to billing cycles. Some periods are designated as extended.

build.gradle
Calendar Anchor
JavaJava
Advanced~4h
Calendar Anchor

Determine the exact date of recurring calendar anchor events. Many organisations schedule recurring events that always.

build.gradle
Call Sign Score
JavaJava
Starter~2h
Call Sign Score

Given a radio call sign, compute its transmission score. Each letter contributes points according to this chart:

build.gradle
Campus Ledger
JavaJava
Advanced~3h
Campus Ledger

Build a campus ledger that keeps track of students and the program level they are assigned to.

build.gradle
Cipher Grid
JavaJava
Advanced~4h
Cipher Grid

Encode a secret dispatch using a cipher grid. Given some English text, output its encoded form.

build.gradle
Cipher Handshake
JavaJava
Starter~2h
Cipher Handshake

Your field team communicates using a cipher handshake — a sequence of physical gestures encoded as a single integer..

build.gradle
Codex Query
JavaJava
Standard~3h
Codex Query

You are building an internal search engine for a digital library archive. Scholars need a tool that searches manuscript.

build.gradle
Codon Chorus
JavaJava
Starter~2h
Codon Chorus

Translate RNA sequences into a codon chorus. RNA is read three bases at a time. Each codon maps to a protein name, and.

build.gradle
Comms Navigator
JavaJava
Standard~3h
Comms Navigator

A shipboard comms navigator keeps answers short. They answer Sure. if you ask them a question.

build.gradle
Config Drift
JavaJava
Starter~2h
Config Drift

You are working on a small internal tool that compares two configuration snapshots.

build.gradle
Cosmic Age
JavaJava
Starter~2h
Cosmic Age

Given an age in seconds, calculate how old someone would be on a set of celestial reference worlds:

build.gradle
Dinner Tab
JavaJava
Standard~3h
Dinner Tab

Implement a RESTful API for managing a shared dinner tab. Four roommates split meals together often, and they need a.

build.gradle
Exact Change
JavaJava
Advanced~4h
Exact Change

A vending machine must return exact change using the fewest possible items from its available denominations. Your task.

build.gradle
Hailstone Cascade
JavaJava
Starter~2h
Hailstone Cascade

Implement a computeStepCount method that computes how many cascade steps a hailstone particle takes to reach unit mass.

build.gradle
Holiday Carol
JavaJava
Standard~3h
Holiday Carol

Implement functions to recite any verse, a range of verses, or the full lyrics of 'The Twelve Days of Christmas'.

build.gradle
Lighthouse Chorus
JavaJava
Standard~3h
Lighthouse Chorus

Generate the verses of a cumulative song about a lighthouse keeper trying to keep a harbor signal line in working order.

build.gradle
Match Tally
JavaJava
Standard~3h
Match Tally

Tally the results of a round-robin sports league into a formatted standings table.

build.gradle
Mission Control
JavaJava
Standard~3h
Mission Control

Build a small mission-control error router. Each operation represents a different launch-control failure path. Your job.

build.gradle
Precinct Lineup
JavaJava
Advanced~4h
Precinct Lineup

Solve the Precinct Lineup logic puzzle by deducing who drinks water and who owns the parrot from a set of constraint.

build.gradle
Press Room
JavaJava
Advanced~4h
Press Room

Build a small press-room renderer. The press team writes updates in a lightweight markup language and wants them turned.

build.gradle
Radar Field
JavaJava
Standard~3h
Radar Field

A radar field marks nearby mines with numeric pings. Given a completed rectangular grid of spaces and asterisks, count.

Relay Ring
JavaJava
Advanced~4h
Relay Ring

A control room keeps a ring of relay tokens in storage. Each token has two ports, and the collection must be arranged.

build.gradle
Riddle Cipher
JavaJava
Standard~3h
Riddle Cipher

An ancient order of scholars communicates using riddle ciphers — arithmetic puzzles where every letter stands for a.

build.gradle