What is java_upgrade CLAUDE.md?

Project instructions for an AI coding assistant working on a Java training course about functional programming, where programs use functions as values and data-processing pipelines. They describe the exercises, files, and Java features covered.

Use them when asking an assistant to explain, edit, or complete exercises in this Java course.

They give the assistant the project context that may not be obvious from the source code, helping it work consistently with the course structure and learning goals.

How kousen/java_upgrade configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to kousen/java_upgrade. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/kousen/java_upgrade/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/kousen/java_upgrade

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/kousen/java_upgrade/claude-md/github.svg)](https://agentmods.dev/instructions/kousen/java_upgrade/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/kousen/java_upgrade/claude-md"><img src="https://agentmods.dev/badge/instructions/kousen/java_upgrade/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/kousen/java_upgrade/claude-md"><img src="https://agentmods.dev/badge/instructions/kousen/java_upgrade/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,000 This file is loaded in full into every session.

When invoked 1,000 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.01000	$0.01000
Opus 5.5	$0.00400	$0.00400
Sonnet 5.5	$0.00200	$0.00200
Haiku 4.5	$0.00100	$0.00100

Measured 2mo ago against content hash db4717f4bfa1, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

java_upgrade CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

CLAUDE.md · 128 lines

How it starts

The opening of the file, as written. The whole thing — 128 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Project Context for Claude Code

Overview

This is a comprehensive Java training project focused on functional programming features in modern Java (Java 8+). The project provides hands-on exercises for students to learn functional programming concepts through practical examples.

Project Structure

java_upgrade/
├── src/main/java/    # Demo code and working examples
├── src/test/java/    # Exercise files with TODOs for students  
├── labs.md           # Comprehensive lab instructions
├── README.md         # Course overview and documentation
├── CLAUDE.md         # This file - project context for Claude Code
└── Java_Upgrade_Slides.pdf  # Course presentation slides

Key Features

20 comprehensive exercises covering functional Java concepts
Main branch contains exercises with TODO comments
Solutions branch contains complete implementations
Each exercise builds on previous concepts
Modern Java idioms throughout (records, var, Stream.toList(), etc.)

Recently Added Exercises

FileFilter Lambda Evolution (Exercise 7)
Lazy Evaluation with Suppliers (Exercise 8)
Book Sorting with Comparators (Exercise 12)
BigDecimal Reduce Operations (Exercise 14)
Parallel Streams (Exercise 14)

Java Features Covered

Lambda Expressions & Functional Interfaces
- Consumer, Supplier, Function, Predicate
- Method references and constructor references
- Functional interface composition
- Lazy evaluation patterns
Stream API
- Basic operations (map, filter, reduce)
- FlatMap for nested structures
- Collectors and advanced aggregations
- Parallel stream processing
- Performance considerations
Modern Java Features
- Optional patterns and chaining
- CompletableFuture async programming
- Records as data carriers
- Interface default/static methods
- Virtual threads (Java 21+)

Important Files and Patterns

Exercise Files to Remember

src/test/java/lambdas/FileFilterExercises.java - Lambda evolution patterns
src/test/java/lambdas/LazyEvaluationExercises.java - Supplier and lazy evaluation
src/test/java/sorting/BookSortingExercises.java - Modern Comparator usage
src/test/java/streams/BigDecimalReduceExercises.java - Reduce operations
src/test/java/streams/ParallelStreamExercises.java - Parallel processing

Read the full file on GitHub · 128 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 128 lines · 1,000 tokens per session scan A db4717f4bfa1

Subscribe to this mod's changes

java_upgrade CLAUDE.md is an instructions file published in the GitHub repository kousen/java_upgrade (164 stars, last pushed 14d ago), licensed MIT. It adds 1,000 tokens to every session, about $0.0040 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Java Languages functional-programming

java_upgrade CLAUDE.md next to 6 instructions from other repositories
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java_upgrade CLAUDE.mdkousen/java_upgrade	Instructions file	164	14d ago	MIT	A	1,000	Claude Code
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java_upgrade: Instructions file for Claude Code