PUBLIC PILOT / WEEK 02 / OBJECTS AND COLLECTIONS

Turn ambiguity into an accepted increment

Monday, September 7–Sunday, September 13, 202624 required hoursReleased

SPRINT GOAL

By Friday, replace procedural gradebook data with encapsulated objects and typed collections, then take an ambiguous request through story, tests, implementation, pull request, and explanation.

EXIT CAN-DO

“I can model state and behavior with Java objects and collections, clarify an ambiguous request, define measurable acceptance criteria, and defend the delivered slice.”

YOUR WORK

You own every story, criterion, test, implementation, command, and GitHub artifact. Keep transfer tasks, the summative, and the fresh micro-change assistant closed.

HOW TO USE EACH BLOCK

Follow the route; make the decisions.

Keep the can-do, acceptance criteria, safety rules, timebox, and evidence fixed. Choose your operating system, editor, names, implementation details, and evidence format unless a block states a technical constraint.

01 / ORIENT
Read the can-do, timebox, required evidence, and stop condition before you open a tool.
02 / RETRIEVE
Write what you remember and one prediction before you consult notes or examples.
03 / LEARN
Use the linked official source for the smallest concept you need; record the section you used.
04 / TRY
Trace or modify a tiny example, then hide it and reproduce the essential behavior yourself.
05 / BUILD
Take the next numbered action in your own repository. You make every learner-owned change.
06 / VERIFY
Run the relevant local check and CI check. Read a failure before changing anything.
07 / EXPLAIN
State what works, why, one tradeoff, and one likely failure case without reading your notes.
08 / RECORD
Save only the listed evidence, update the Issue, and choose one next action before you stop.

MONDAY

Classes, constructors, and encapsulation

4 hours

CAN-DO

I can design a class with private state, a validating constructor, and behavior methods, and explain why the state is not public.

USE THESE SOURCES

dev.java: Classes and Objects ↗

WHAT YOU DO

Write the story and acceptance criteria before implementation: Replace parallel score arrays with Student and Quiz domain objects.
Keep fields private and prevent invalid required state during construction.
Place behavior on the relevant object instead of manipulating public fields.
Test valid construction and one rejected value while keeping all Week 1 behavior green.
Explain object identity, state, behavior, and one encapsulation tradeoff.

WHAT YOU KEEP

Your story and criteria commit before implementation
JUnit results for valid and rejected construction
An explain-back on the design tradeoff

YOUR CHOICE

You choose class names, constructor shape, and which behavior belongs on Student or Quiz. Keep required state private, reject invalid construction, and preserve accepted Week 1 behavior.

CHECK BEFORE YOU MOVE ON

The story and acceptance criteria are committed before the first domain implementation.
A caller can use the required behavior without reading or changing a public field.

TUESDAY

Strings, parsing, and immutability

4 hours · Simple-method condition

CAN-DO

I can explain String immutability, choose StringBuilder for accumulation, and parse delimited synthetic input with useful failure behavior.

USE THESE SOURCES

dev.java: Numbers and Strings ↗

WHAT YOU DO

Use the simple sequence: read, predict, and complete the authentic Issue.
Open the story: Parse a synthetic name-and-scores line without leaking a stack trace to the user.
Define the whitespace policy before coding and test malformed, empty, and valid lines.
Make error output identify the rejected field without including real personal data.
Explain why combining a String does not mutate the original and when repeated concatenation should become a builder.

WHAT YOU KEEP

Your prediction, policy, and tests
A passing parser with useful failure behavior
Your immutability and StringBuilder explanation

YOUR CHOICE

You choose the delimiter, whitespace policy, error wording, and whether accumulation needs StringBuilder. Publish the input grammar first and use synthetic values only.

CHECK BEFORE YOU MOVE ON

Malformed, empty, and valid lines have distinct expected results and none prints a stack trace to the user.
You can point to each newly created String while explaining why the original value remains unchanged.

WEDNESDAY

List and safe iteration

4 hours

CAN-DO

I can choose a List instead of an array for variable-sized data, use a generic element type, and avoid unsafe mutation during iteration.

USE THESE SOURCES

dev.java: Collections Framework ↗

WHAT YOU DO

Complete the sealed 20-minute Tuesday transfer task first, without AI.
Open the story: Allow the synthetic roster to add and drop students at runtime.
Specify duplicate and unknown-ID behavior and avoid exposing a modifiable internal collection.
Test add, drop, and iteration behavior.
Explain the generic type, your iteration choice, one mutation hazard, and why an array is no longer the best fit.

WHAT YOU KEEP

Your sealed transfer score and time
Tests and implementation for add, drop, and iteration
Your collection-choice explanation

YOUR CHOICE

You choose the concrete List implementation, iteration style, and read-only view or copy returned to callers. Keep the public contract typed and prevent outside mutation of internal state.

CHECK BEFORE YOU MOVE ON

Duplicate-add and unknown-drop policies are explicit before implementation.
A test proves that a caller cannot mutate the roster by changing a returned collection.

THURSDAY

Map, equality, and hashing

4 hours · Full-method condition

CAN-DO

I can aggregate values with a typed Map and predict how equality and hash behavior affect key lookup.

USE THESE SOURCES

dev.java: Collections Framework ↗

WHAT YOU DO

Use the full learning sequence from retrieval through explain-back.
Open the story: Show running averages keyed by a synthetic student ID.
Specify missing-ID and duplicate-ID policies before implementation.
Test repeated updates and write a failing case that distinguishes reference identity from value equality.
Explain a key-lookup failure caused by an incorrect equality assumption. Keep all identifiers synthetic.

WHAT YOU KEEP

Your worked, faded, and unaided practice record
Tests covering repeated updates and equality behavior
Your lookup-failure explanation

YOUR CHOICE

You choose the Map implementation and whether the key is a validated ID value or a domain object. Keep equals and hashCode consistent with that decision and document duplicate handling.

CHECK BEFORE YOU MOVE ON

The same logical key finds the same entry after repeated updates, and your test would fail under the wrong equality rule.
Missing and duplicate keys follow the policy you wrote before implementation.

FRIDAY

Ambiguous request to accepted Increment

4 hours

CAN-DO

I can turn an ambiguous stakeholder request into a small story with measurable criteria, implement it, and defend the slice.

WHAT YOU DO

Complete the sealed 20-minute Thursday transfer task first, without AI.
Reveal the stakeholder prompt: Show me who needs help.
Before coding, write at least three clarifying questions, define needs help using synthetic scores, state non-goals, and identify one privacy risk.
Write one small story with testable criteria, implement only that slice, and keep existing tests green.
Open a pull request with CI evidence, then give a five-minute Sprint Review showing the behavior and one rejected interpretation.

WHAT YOU KEEP

Your sealed transfer score and time
Clarifying questions, story, non-goals, criteria, and privacy risk
A green pull request plus Sprint Review evidence

YOUR CHOICE

You choose the threshold, output shape, and smallest useful interpretation of needs help after asking clarifying questions. Keep non-goals and the synthetic-data privacy boundary visible.

CHECK BEFORE YOU MOVE ON

Each acceptance criterion can be demonstrated as pass or fail without subjective judgment.
The pull request implements only the accepted slice and names at least one plausible interpretation you rejected.

SUNDAY

Audition and method gate

Exactly 4 hours

WHAT YOU DO

Push all weekday work before the clock begins.
Release the unseen summative, close the assistant, and complete the full 60-minute assessment.
Release a fresh micro-change in a new session, close the assistant, and complete the full 45-minute change.
Archive your commit, test, CI, and explanation evidence. Score the fixed method check and record retain or simplify.
Run the independent review only after the assessed work is sealed, then apply the fixed audition checklist.

WHAT YOU KEEP

A summative score of at least 75 or an honest remediation record
A micro-change score of at least 75 with at least 28 of 40 behavior points
Your method decision, retrospective, and one next step

YOUR CHOICE

You choose how to archive evidence and whether to retain or simplify the learning method after scoring it. Keep both assessment prompts unseen, clocks fixed, and assistant access closed until the work is sealed.

CHECK BEFORE YOU MOVE ON

The summative and micro-change each have their own start time, stop time, commit, test result, CI result, and explanation evidence.
Your retain-or-simplify decision cites observed results from both weeks instead of preference alone.

EXIT CHECK

Finish only when each line is true

Across Weeks 1 and 2, you completed at least eight of ten weekday blocks with Issue, commit, result, can-do, and explain-back evidence.
You completed both Sunday assessment blocks without assistant help.
Across the two-week audition, all required work fit within 48 scheduled hours; optional Saturday time did not rescue the result.
The Week 2 summative and fresh micro-change each meet their fixed pass conditions.
You recorded a retain-or-simplify method decision and no more than one unexcused incomplete day per week.

Finish only when each line is true

Across Weeks 1 and 2, you completed at least eight of ten weekday blocks with Issue, commit, result, can-do, and explain-back evidence.

You completed both Sunday assessment blocks without assistant help.

Across the two-week audition, all required work fit within 48 scheduled hours; optional Saturday time did not rescue the result.

The Week 2 summative and fresh micro-change each meet their fixed pass conditions.

You recorded a retain-or-simplify method decision and no more than one unexcused incomplete day per week.