An Engineer's musings

Guice: Dependency Injection You Can Actually Read

Tue, 02 Dec 2025 00:00:00 GMT

An introduction to Guice, Google's dependency injection framework for the JVM — why hand-wiring hurts, what DI really is, and how Guice keeps the wiring explicit. With Kotlin and Java side by side.

Your First Guice Injector: Wiring That Builds Itself

Sat, 06 Dec 2025 00:00:00 GMT

A hands-on guice injector tutorial — the Gradle dependency, @Inject constructor injection, AbstractModule, and Guice.createInjector — with Kotlin and Java side by side.

Guice Bindings: Five Ways to Answer One Question

Wed, 10 Dec 2025 00:00:00 GMT

A tour of guice bindings — linked, instance, untargeted, constructor, just-in-time, and provider — and when to reach for each, in Kotlin and Java.

Guice Providers and @Provides: Construction Logic Without the new Keyword

Sun, 14 Dec 2025 00:00:00 GMT

How a guice provider and an @Provides method give you somewhere to put real construction logic, with lazy creation, scope-crossing, and qualifiers — in Kotlin and Java.

Two of the Same Thing: Telling Identical Types Apart in Guice

Thu, 18 Dec 2025 00:00:00 GMT

How guice qualifiers and @Named let you bind two implementations of the same type and inject the right one — custom annotations versus stringly-typed names, in Kotlin and Java.

Scopes: How Long Should an Object Hang Around?

Mon, 22 Dec 2025 00:00:00 GMT

How Guice scopes control object lifetimes, why @Singleton means one instance per injector, and how to apply it from the class or the binding — with Kotlin and Java side by side.

Composing Modules: One Big Module Is a Smell

Fri, 26 Dec 2025 00:00:00 GMT

How to organize guice modules as the graph grows — install, multiple modules, Modules.combine, and Modules.override for tests and environments — with Kotlin and Java side by side.

When It Breaks: Reading Guice Stack Traces Without Crying

Tue, 30 Dec 2025 00:00:00 GMT

How to read and fix a guice CreationException, the 'no implementation was bound' miss, and a circular dependency — with the fixes in Kotlin and Java.

Multibindings: How to Build a Plugin System Without a Registry

Sat, 03 Jan 2026 00:00:00 GMT

Using the guice multibinder, MapBinder, and OptionalBinder so many modules can contribute to one Set, Map, or Optional — multibindings explained with Kotlin and Java side by side.

TypeLiteral: Smuggling Generics Past the Erasure Checkpoint

Wed, 07 Jan 2026 00:00:00 GMT

How Guice TypeLiteral captures full generic types so you can bind and inject things like Repository, with Kotlin and Java side by side — beating type erasure at its own game.

Assisted Injection: When Half the Object Comes From Guice and Half From You

Sun, 11 Jan 2026 00:00:00 GMT

How guice assisted injection and @Assisted let Guice supply the dependencies while the caller supplies the runtime values — building objects that need both, in Kotlin and Java.

Guice AOP: Wrapping Methods Without Touching Them

Thu, 15 Jan 2026 00:00:00 GMT

A practical guide to guice aop — using a method interceptor to add timing, logging, and transactions cross-cuttingly, with the limitations laid bare, in Kotlin and Java.

Private Modules: What Happens in the Module Stays in the Module

Mon, 19 Jan 2026 00:00:00 GMT

How guice private modules encapsulate bindings so internal wiring never leaks into the global graph — and how to run two isolated copies of a subsystem, in Kotlin and Java.

Custom Scopes: Teaching Guice a New Lifetime

Fri, 23 Jan 2026 00:00:00 GMT

How to write a guice custom scope by implementing the Scope interface — a ThreadLocal-backed scope with enter/exit, a scope annotation, and bindScope — with Kotlin and Java side by side.

Guice on the Web: The Servlet Extension Nobody Mentions Anymore

Tue, 27 Jan 2026 00:00:00 GMT

How the guice servlet extension wires servlets, filters, and the @RequestScoped / @SessionScoped scopes onto a classic web stack — and when it's still the right tool — with Kotlin and Java side by side.

Testing Guice, Writing It in Kotlin, and Not Shooting Yourself in the Foot

Sat, 31 Jan 2026 00:00:00 GMT

Guice testing without the container, swapping fakes with Modules.override and BoundFieldModule, Kotlin idioms, the Jakarta migration, and guice best practices — in Kotlin and Java.

Classes Workbook (Part 1)

Wed, 25 Feb 2026 00:00:00 GMT

Eleven short exercises on Kotlin classes — declarations, primary constructors, properties, init blocks, custom accessors, encapsulation, and inheritance.

Class Types Workbook (Part 2)

Tue, 03 Mar 2026 00:00:00 GMT

Ten short exercises on Kotlin's specialized classes — data classes, enums, sealed hierarchies, objects and companions, inner classes, and value classes.

Collections Workbook

Sat, 07 Feb 2026 00:00:00 GMT

Eleven short exercises on Kotlin collections — read-only versus mutable, the factory functions, map access, getOrDefault, the plus and minus operators, and read-only signatures.

Control Flow Workbook

Wed, 14 Jan 2026 00:00:00 GMT

Eleven short exercises on Kotlin control flow — if as an expression, ranges, for loops, membership with in, indices, and labelled break.

Coroutines Workbook

Wed, 20 May 2026 00:00:00 GMT

Nine short exercises on Kotlin coroutines — suspend functions, suspension points, launch, async and await, coroutineScope, structured concurrency, and dispatchers.

Data Types Workbook

Fri, 02 Jan 2026 00:00:00 GMT

Eleven short exercises on Kotlin's basic types — val and var, the number types, explicit conversions, strings and templates, nullability, and Unit and Nothing.

Delegation Workbook

Tue, 14 Apr 2026 00:00:00 GMT

Nine short exercises on Kotlin delegation — class delegation with by, lazy and observable properties, map-backed properties, writing a custom delegate, and lateinit versus lazy.

Destructuring Workbook

Thu, 02 Apr 2026 00:00:00 GMT

Ten short exercises on Kotlin destructuring — declarations, the componentN convention, data classes, map entries, withIndex, lambda parameters, skipping with underscore, and custom components.

Enums Workbook

Mon, 09 Mar 2026 00:00:00 GMT

Ten short exercises on Kotlin enums — constants, exhaustive when, constructor properties, methods, per-constant overrides, the built-in members, and implementing interfaces.

Equality Workbook

Fri, 27 Mar 2026 00:00:00 GMT

Ten short exercises on Kotlin equality — structural == versus referential ===, null-safe comparison, data-class equals and hashCode, and Comparable with the comparison operators.

Exceptions Workbook

Sun, 26 Apr 2026 00:00:00 GMT

Ten short exercises on Kotlin exception handling — try/catch as an expression, require and check, use for resources, runCatching and Result, Nothing, and sealed result types.

Extension Functions Workbook

Sat, 21 Mar 2026 00:00:00 GMT

Ten short exercises on Kotlin extensions — declaring extension functions and properties, the receiver, static resolution, nullable receivers, and members winning over extensions.

Functions Workbook

Thu, 08 Jan 2026 00:00:00 GMT

Fifteen short exercises on Kotlin functions — single-expression bodies, default and named arguments, vararg, and top-level and local functions. Solutions reveal on click.

Generics Workbook

Mon, 20 Apr 2026 00:00:00 GMT

Nine short exercises on Kotlin generics — generic functions and classes, declaration-site variance with out and in, star projections, and reified type parameters.

Interfaces Workbook

Sun, 15 Mar 2026 00:00:00 GMT

Ten short exercises on Kotlin interfaces — implementing them, default methods, property contracts, resolving clashes between defaults, functional interfaces, and interface inheritance.

Java Interop Workbook

Sat, 02 May 2026 00:00:00 GMT

Ten short exercises on Kotlin/Java interop — getters as properties, platform types, SAM conversion, and the @Jvm annotations that make Kotlin pleasant to call from Java.

Lambdas Workbook (Part 3): Closures

Sat, 14 Feb 2026 00:00:00 GMT

Eleven short exercises on closures — capturing parameters, capturing and mutating a var, returning a stateful lambda, shared state, and capturing a loop variable.

Lambdas Workbook (Part 2): The Collection API

Thu, 12 Feb 2026 00:00:00 GMT

Thirteen short exercises on lambdas at work — forEach, the trailing-lambda convention, map and filter, chaining, the any/all/count/find/sumOf toolkit, and writing your own higher-order function.

Lambdas Workbook (Part 5): inline and Receivers

Wed, 18 Feb 2026 00:00:00 GMT

Eleven short exercises on inline functions and lambdas with a receiver — marking a function inline, reified, receiver lambda types, apply and buildString, and writing a receiver-based builder.

Lambdas Workbook (Part 4): References, Returns, and Anonymous Functions

Mon, 16 Feb 2026 00:00:00 GMT

Twelve short exercises on the four kinds of function reference, non-local returns and labels, and anonymous functions.

Lambdas Workbook (Part 1): The Basics

Tue, 10 Feb 2026 00:00:00 GMT

Twelve short exercises on the lambda basics — defining and calling, parameters and results, function types, the implicit it, and multi-line bodies.

Null Safety Workbook

Sun, 01 Feb 2026 00:00:00 GMT

Ten short exercises on Kotlin null safety — safe calls, the Elvis operator, !!, safe casts, ?.let, lateinit, nullable collections, and platform types.

Operator Overloading Workbook

Thu, 14 May 2026 00:00:00 GMT

Ten short exercises on Kotlin operator overloading — plus, get and set, invoke, contains, compareTo, compound assignment, unaryMinus, and making a type iterable.

Scope Functions Workbook

Fri, 08 May 2026 00:00:00 GMT

Ten short exercises on Kotlin's scope functions — let, run, with, apply, and also, decided by receiver-versus-parameter and result-versus-object, plus takeIf and takeUnless.

Smart Casts Workbook

Mon, 26 Jan 2026 00:00:00 GMT

Ten short exercises on Kotlin smart casts — is and !is, null-check narrowing, smart casts in when, combined conditions, early returns, and where they don't apply.

Visibility Workbook

Wed, 08 Apr 2026 00:00:00 GMT

Ten short exercises on Kotlin visibility — the default, private and protected, the module-scoped internal, private setters, private constructors, and file organization.

when Workbook

Tue, 20 Jan 2026 00:00:00 GMT

Ten short exercises on Kotlin's when — as a statement and an expression, with and without a subject, range and type matching, multiple values per branch, and exhaustiveness.

A Kotlin Class Is Mostly Its Header

Tue, 24 Feb 2026 00:00:00 GMT

Declaring classes, primary and secondary constructors, properties, init blocks, encapsulation, and why Kotlin classes are final by default. Part 1 of a two-part tour.

One Keyword Does the Work: Kotlin's data, enum, sealed, and object

Mon, 02 Mar 2026 00:00:00 GMT

Beyond the plain class — data classes, enums, sealed hierarchies, objects and companions, nested vs inner, and value classes, each with a small example. Part 2 of two.

Kotlin Collections Are Read-Only Until You Say Otherwise

Fri, 06 Feb 2026 00:00:00 GMT

Lists, sets, and maps in Kotlin: the read-only versus mutable split, the factory functions, why read-only isn't immutable, and how it shapes your function signatures.

Kotlin's if Returns a Value, So There's No Ternary

Tue, 13 Jan 2026 00:00:00 GMT

Control flow in Kotlin: if and when as expressions, for loops over ranges and collections, the range operators, while loops, and labelled break and continue.

Coroutines: Asynchronous Code That Reads Like It Isn't

Tue, 19 May 2026 00:00:00 GMT

An introduction to Kotlin coroutines — suspend functions, why they read sequentially, structured concurrency with async and await, and what suspension actually does.

In Kotlin, There Are No Primitives

Thu, 01 Jan 2026 00:00:00 GMT

A tour of Kotlin's basic types: val and var, the number types, no implicit conversions, strings and templates, null as part of the type, and Any/Unit/Nothing.

The by Keyword: Delegation Without the Boilerplate

Mon, 13 Apr 2026 00:00:00 GMT

Class delegation that makes composition as cheap as inheritance, and delegated properties like lazy and observable that move a property's logic into a reusable object.

Destructuring: Unpacking an Object in One Line

Wed, 01 Apr 2026 00:00:00 GMT

Pulling several values out of an object at once with destructuring declarations, the componentN convention behind it, and using it in loops and lambdas.

Enums in Kotlin: Small, Useful, and More Powerful Than They Look

Sun, 08 Mar 2026 00:00:00 GMT

Kotlin enums feel familiar coming from Java, but they can carry data, behavior, and exhaustive when-handling. A build-up from the basics.

In Kotlin, == Is the One You Actually Want

Thu, 26 Mar 2026 00:00:00 GMT

Structural equality with == versus referential equality with ===, why the Java string bug can't happen here, and how Comparable wires up the comparison operators.

Unchecked and Unbothered: How Kotlin Rethinks Java's Exception Handling

Sat, 25 Apr 2026 00:00:00 GMT

Kotlin drops checked exceptions entirely. Here's what that changes day to day, and the compiler trickery that makes it work.

Extension Functions: Add Methods to Classes You Don't Own

Fri, 20 Mar 2026 00:00:00 GMT

Declaring extension functions and properties, what the receiver and this mean, why extensions resolve statically rather than virtually, and nullable receivers.

In Kotlin, Functions Don't Need a Class

Wed, 07 Jan 2026 00:00:00 GMT

Declaring functions with fun, single-expression bodies, default and named arguments that retire overloads, vararg, and top-level and local functions.

Kotlin Generics: Variance Without the Wildcards

Sun, 19 Apr 2026 00:00:00 GMT

Generic functions and classes, declaration-site variance with out and in instead of Java's wildcards, star projections, and reified type parameters on inline functions.

Kotlin Interfaces Carry More Than Java's Ever Could

Sat, 14 Mar 2026 00:00:00 GMT

Interfaces with default method bodies, abstract properties, implementing several at once and resolving the clashes, and how to choose between an interface and an abstract class.

Calling Java From Kotlin (and Back) Without Friction

Fri, 01 May 2026 00:00:00 GMT

How Kotlin sees Java getters as properties, SAM conversion for functional interfaces, and the @Jvm annotations that make Kotlin code pleasant to call from Java.

Closures: What a Lambda Remembers

Fri, 13 Feb 2026 00:00:00 GMT

A lambda can capture variables from the scope where it was written — and in Kotlin it can even change them. The mental model, the Java contrast, and the gotchas. Part 3 of five.

Lambdas at Work: Transforming Collections

Wed, 11 Feb 2026 00:00:00 GMT

Where lambdas earn their keep: higher-order functions, the trailing-lambda convention, map and filter and the rest of the collection toolkit, chaining, and writing your own. Part 2 of five.

Why Lambdas Are Free, and Lambdas That Read Like Syntax

Tue, 17 Feb 2026 00:00:00 GMT

The performance model behind lambdas — inline functions and why they cost nothing — and lambdas with a receiver, the trick behind apply, buildString, and Kotlin's DSLs. Part 5 of five.

Lambdas, Sharpened: References, Returns, and Anonymous Functions

Sun, 15 Feb 2026 00:00:00 GMT

Replacing a lambda with a function reference, the four kinds of reference, the surprising rules for return inside a lambda and the labels that tame them, and anonymous functions. Part 4 of five.

A Kotlin Lambda Is a Value You Can Pass Around

Mon, 09 Feb 2026 00:00:00 GMT

The gentle start to lambdas: code as a value, defining versus calling, parameters and results, function types, the implicit it, and multi-line bodies. Part 1 of five.

Kotlin's Billion-Dollar Fix: Null Lives in the Type System

Sat, 31 Jan 2026 00:00:00 GMT

The full null-safety toolkit: safe calls, the Elvis operator, !!, safe casts, ?.let, lateinit, nullable collections, and the platform types that leak in from Java.

Operator Overloading, Kept on a Leash

Wed, 13 May 2026 00:00:00 GMT

Kotlin allows operator overloading but only through a fixed set of conventionally-named functions: plus, get, invoke, contains, and friends — power with guardrails.

let, run, apply, also, with: Picking the Right Scope Function

Thu, 07 May 2026 00:00:00 GMT

The five scope functions decided by two questions — how the object is referenced (this or it) and what the block returns (the result or the object itself).

Kotlin Smart Casts: Stop Telling the Compiler What It Already Knows

Sun, 25 Jan 2026 00:00:00 GMT

How Kotlin's smart casts remove the check-then-cast tax from everyday code, and the rules that decide when they kick in.

Kotlin Has a Visibility Level Java Doesn't: internal

Tue, 07 Apr 2026 00:00:00 GMT

The four visibility modifiers, why public is the default, what internal means at the module level, and how Kotlin's file structure frees you from one-class-per-file.

Kotlin's when Is the New switch — And if, And instanceof

Mon, 19 Jan 2026 00:00:00 GMT

Kotlin's when quietly replaces switch, long if/else ladders, and instanceof-with-cast. A tour of the parts that matter.

Ktor Is Just Kotlin, All the Way Down

Mon, 02 Mar 2026 00:00:00 GMT

Meet Ktor — JetBrains' lightweight, coroutine-first framework for Kotlin backends. Why it feels different from Spring, and your first server in a handful of lines.

From Zero to a Running Server: Setting Up Ktor

Sun, 08 Mar 2026 00:00:00 GMT

Bootstrap a real Ktor project with Gradle and IntelliJ — the project generator, the build file, the two ways to start a server, and live reload while you code.

Routing: Turning URLs Into Code

Sat, 14 Mar 2026 00:00:00 GMT

The Ktor routing DSL from the ground up — HTTP verbs, path and query parameters, nested routes, and how to split your routes into clean, composable functions.

The Anatomy of a Call: Requests and Responses

Fri, 20 Mar 2026 00:00:00 GMT

Everything flows through `call`. Read headers and bodies from the request, and reply with the right status codes, content types, and headers from the response.

Speaking JSON: Content Negotiation in Ktor

Thu, 26 Mar 2026 00:00:00 GMT

Install one plugin, annotate your data classes, and Ktor serializes Kotlin objects to JSON and parses JSON back into objects — no manual string wrangling.

Your First Real API: CRUD, End to End

Wed, 01 Apr 2026 00:00:00 GMT

Routing, JSON, and status codes come together into a complete task API — list, fetch, create, update, and delete — backed by a clean repository.

Before module() Becomes a Monster

Tue, 07 Apr 2026 00:00:00 GMT

Ktor gives you no structure — that's your job. Split configuration into focused extension functions, organize by concern, and read typed values from application.yaml.

One Place for Things Going Wrong: StatusPages

Mon, 13 Apr 2026 00:00:00 GMT

Stop scattering error responses through every handler. Throw meaningful exceptions, map them to status codes and clean JSON in one plugin, and keep your routes about the happy path.

Giving Your Data a Home: Persistence with Exposed

Sun, 19 Apr 2026 00:00:00 GMT

Swap the in-memory map for a real SQL database using Exposed, JetBrains' Kotlin SQL framework — tables as objects, type-safe queries, and transactions that play nicely with coroutines.

Who Builds the Objects? Dependency Injection in Ktor

Sat, 25 Apr 2026 00:00:00 GMT

Ktor has no DI container — and that's fine until it isn't. Start with honest manual wiring, add a service layer, then graduate to Koin when hand-threading dependencies stops scaling.

Locking the Doors: JWT Authentication

Fri, 01 May 2026 00:00:00 GMT

Issue signed tokens at login, verify them on protected routes with Ktor's Authentication plugin, and read the logged-in user out of the request — the standard auth flow for APIs.

Don't Trust the Client: Validation and Security

Thu, 07 May 2026 00:00:00 GMT

Reject bad input before it reaches your logic with RequestValidation, open your API to browsers safely with CORS, and survive the public internet with rate limiting and sane headers.

Flying With Instruments: Logging and Metrics

Wed, 13 May 2026 00:00:00 GMT

When production misbehaves, you need to see inside. Add request logging, trace a single request across log lines with a call ID, and expose Prometheus metrics — all as plugins.

Calling Out: The Ktor HTTP Client

Tue, 19 May 2026 00:00:00 GMT

Ktor isn't just a server. The same library gives you a coroutine-based HTTP client for calling other APIs — with JSON, timeouts, and defaults configured the way you'd expect.

Keeping the Line Open: WebSockets

Mon, 25 May 2026 00:00:00 GMT

Request/response can't push. WebSockets give you a persistent, two-way channel — perfect for live updates and chat. Echo a message, then broadcast to every connected client.

Proving It Works: Testing Ktor Apps

Sun, 31 May 2026 00:00:00 GMT

Ktor runs your whole app in-memory for tests — no ports, no network, no waiting. Test routes with a real HTTP client, assert on JSON, exercise auth, and swap in fakes.

Shipping It: From Fat JAR to Production

Sat, 06 Jun 2026 00:00:00 GMT

Package your Ktor app into a single runnable JAR, wrap it in a Docker image, drive its config from environment variables, and walk the checklist before it faces real traffic.

I Stopped My 2019 Intel MacBook Pro From Bleeding Battery Overnight — Here's What Actually Worked

Tue, 19 Aug 2025 00:00:00 GMT

An Intel Mac draining ~28% overnight wasn't the failing battery — it was one Continuity feature holding the CPU awake. The one-toggle fix, with measured results.

Diagnosing a Sluggish Intel Mac: A Field Manual

Tue, 12 Aug 2025 00:00:00 GMT

Eight terminal commands that tell you why an Intel Mac feels slow — swap, memory pressure, runaway CPU, rogue VMs, and sleep blockers — and how to read each one.

What Is Misk? Cash App's Kotlin Microservice Container, Explained

Thu, 12 Feb 2026 00:00:00 GMT

Misk is the open-source Kotlin microservice container that runs hundreds of services at Cash App. Here's what a container is, how it differs from Spring Boot and Ktor, and when to reach for it.

Misk Getting Started: Your First Service, End to End

Tue, 17 Feb 2026 00:00:00 GMT

A hands-on misk getting started walkthrough: the Gradle and BOM setup, the MiskApplication entry point, the module list, config YAML, and running the exemplar service locally.

Misk Guice Dependency Injection: KAbstractModule and the Module Way

Sun, 22 Feb 2026 00:00:00 GMT

How misk dependency injection works: KAbstractModule, bindings, qualifiers, and multibindings in Kotlin — and why Misk chose Guice over Spring-style component scanning.

Misk Service Lifecycle: Readiness and Graceful Shutdown Done Right

Fri, 27 Feb 2026 00:00:00 GMT

How the misk service lifecycle works: Guava ServiceManager, dependency ordering with dependsOn and enhancedBy, the ReadyService pattern, warmup, and misk graceful shutdown that drains in-flight work.

Misk Web Actions: Building HTTP Endpoints (and How They Beat @RestController)

Wed, 04 Mar 2026 00:00:00 GMT

Write a misk web action: WebAction, @Get/@Post, path and query params, typed request and response bodies, and status control with Response — plus why Misk favors one action class per endpoint.

Misk JSON, Forms, Multipart & Downloads: Marshalling the Wire

Mon, 09 Mar 2026 00:00:00 GMT

How Misk moves bytes: JSON marshalling with Moshi, form-encoded bodies, misk multipart upload handling via MultipartReader, and file downloads with Content-Disposition.

Misk Interceptors: Cross-Cutting Concerns Without the Magic

Sat, 14 Mar 2026 00:00:00 GMT

A guide to the misk interceptor model: NetworkInterceptor vs ApplicationInterceptor, where each sits in the request pipeline, the Factory that opts them in per action, and how to write your own.

Misk gRPC and Protobuf: Wire-Generated Services, JSON for Free

Thu, 19 Mar 2026 00:00:00 GMT

Build a misk grpc endpoint with protobuf and Wire: define the proto, generate server interfaces, implement a gRPC action, and get an automatic JSON variant of every protobuf action.

Misk Authentication & Access Control: Callers, Capabilities, and Audit

Tue, 24 Mar 2026 00:00:00 GMT

How misk authentication and access control work: @Authenticated, the MiskCaller model of services and capabilities, custom access annotations, the AccessInterceptor that enforces them, and audit logging.

Misk OPA Authorization: Type-Safe Policy with misk-policy

Sun, 29 Mar 2026 00:00:00 GMT

Externalize complex authorization with misk opa integration: wire Misk to Open Policy Agent via misk-policy, write type-safe OpaPolicyEngine queries, and test policy locally.

Misk Crypto & Secrets: Keys, Encryption, and Config Secrets Done Safely

Fri, 03 Apr 2026 00:00:00 GMT

How misk crypto wires Tink primitives from KMS-encrypted keys, and how misk secrets keep credentials out of code, logs, and dashboards via Secret and @Redact.

Misk JDBC & Data Sources: Connection Pooling and Read/Write Splitting

Wed, 08 Apr 2026 00:00:00 GMT

How misk jdbc wires a real database: misk datasource config, Hikari connection pooling, read/write splitting via reader/writer clusters, and the JDBC-layer Transacter.

Misk Hibernate and the Transacter: Persistence Without the Footguns

Mon, 13 Apr 2026 00:00:00 GMT

How misk hibernate models entities and queries, and how the misk transacter gives you block-based transactions, retries, and replica reads without ever handing you a raw Hibernate session.

Misk Schema Migrations: Versioned SQL Without Flyway

Sat, 18 Apr 2026 00:00:00 GMT

How misk schema migration works — versioned .sql files, the schema_version table, the standalone Gradle plugin, and why it's a credible misk flyway alternative.

Misk SqlDelight, jOOQ & Vitess: Beyond Hibernate, and Sharding at Scale

Thu, 23 Apr 2026 00:00:00 GMT

Why misk sqldelight and jOOQ are the type-safe alternatives to Hibernate, plus misk vitess sharding for horizontal MySQL scale and the Vitess Gradle plugin.

Misk Redis & Caching: The Lettuce-Backed Client and Cache Patterns

Tue, 28 Apr 2026 00:00:00 GMT

How misk redis and misk caching work: the Jedis-backed Redis client, the newer Lettuce module, RedisModule wiring, RedisConfig YAML, and a FakeRedis for tests.

Misk Rate Limiting & Tokens: Bucket4j Backends and Safe ID Generation

Sun, 03 May 2026 00:00:00 GMT

How misk rate limiting and misk tokens work: the wisp RateLimiter backed by Bucket4j (Redis, MySQL, DynamoDB), and TokenGenerator for unguessable IDs.

Misk Job Queues: Transactional, SQS-Backed Background Work

Fri, 08 May 2026 00:00:00 GMT

How the misk job queue works: defining handlers, enqueuing, and the misk sqs (misk-aws2-sqs) backend — plus the transactional spooling table and its exactly-once-ish guarantee.

Misk Cron: Cluster-Safe Scheduled Jobs

Wed, 13 May 2026 00:00:00 GMT

How misk cron schedules recurring work: the @CronPattern annotation, the Runnable contract, CronModule wiring, and the lease-based coordination that stops every replica from firing the same job.

Misk Distributed Leases & Leader Election: Coordinating a Cluster

Mon, 18 May 2026 00:00:00 GMT

How a misk distributed lease works and how to use it for misk leader election: the Lease/LeaseManager API, the SQL and cluster-aware backends, and the time-bound correctness caveats.

Misk Configuration & Environments: YAML, Secrets, and Wisp

Sat, 23 May 2026 00:00:00 GMT

A deeper look at misk config and misk environments: the Deployment model, the full YAML resolution and merge order, Secret loading, redaction, and Wisp's standalone config and deployment helpers.

Misk Observability: Prometheus Metrics, Structured Logging, and Tracing

Thu, 28 May 2026 00:00:00 GMT

How misk observability fits together: misk metrics prometheus counters, gauges and histograms, structured logging with MDC tags, sampling, and OpenTracing-backed tracing on Datadog.

Misk Testing: @MiskTest, Fakes, and Fast Integration Tests

Tue, 02 Jun 2026 00:00:00 GMT

How misk testing works: @MiskTest stands up a real injector, fakes ship as modules, and WebTestClient gives you fast integration tests against a running server — plus action registration checks.

The Misk Admin Dashboard: Server-Rendered with Hotwire and Tailwind

Sun, 07 Jun 2026 00:00:00 GMT

How the misk admin dashboard works and how to build tabs on its misk hotwire tailwind stack — kotlinx.html server-side rendering, the deprecated React misk-web, and AdminDashboardAccess gating.

Exposing Your Misk Service to AI: An MCP Server with misk-mcp

Mon, 08 Jun 2026 00:00:00 GMT

Turn a Misk service into a Model Context Protocol server with misk mcp: define tools, resources, and prompts, then expose them to LLMs over StreamableHTTP or WebSocket.

Hello, Turtle! Move and Turn

Mon, 02 Feb 2026 00:00:00 GMT

Day one of Python for Kids: meet the turtle, write real Python, and steer it around the screen — forward, back, and turning corners — all in your browser.

Shapes and the Angle Rule

Thu, 05 Feb 2026 00:00:00 GMT

What do those turning numbers really mean? Learn the one simple rule that lets you draw a triangle, a pentagon, a hexagon — any shape you want.

Pick Up the Pen and Add Color

Mon, 09 Feb 2026 00:00:00 GMT

Move without drawing, change colors and line thickness, and fill your shapes with bright color. Your drawings are about to come alive.

Build-It Project: Draw a House

Thu, 12 Feb 2026 00:00:00 GMT

Your first real project! Put moves, turns, and colors together to build a house with a roof — then make it your own with a door, a window, and a sun.

Loops: The Lazy Way to Draw

Mon, 16 Feb 2026 00:00:00 GMT

Why type the same lines over and over? Meet the loop — Python's way to repeat — and draw any shape in just two lines instead of a dozen.

Spinning Loops into Patterns

Thu, 19 Feb 2026 00:00:00 GMT

Repeat a shape while turning a little each time and watch stars, bursts, and flower-like patterns appear. This is where code starts to feel like magic.

Variables: Give Your Numbers Names

Mon, 23 Feb 2026 00:00:00 GMT

Store a number under a name and reuse it everywhere — change it once and your whole drawing updates. Then make a number grow inside a loop to draw a spiral.

Build-It Project: A Spiral Masterpiece

Thu, 26 Feb 2026 00:00:00 GMT

Project day! Combine loops and a growing variable into a smooth, colorful spiral — then turn the knobs to make a one-of-a-kind piece of art.

Functions: Teach the Turtle a New Trick

Mon, 02 Mar 2026 00:00:00 GMT

Give a drawing a name once, then use it again and again. Functions let you build your own commands — like teaching the turtle a brand-new trick.

Functions That Take Inputs

Thu, 05 Mar 2026 00:00:00 GMT

Give your functions a knob to turn. With parameters, one function can draw big shapes, small shapes, and any color — and a loop can call it with a different value each time.

A Splash of Randomness

Mon, 09 Mar 2026 00:00:00 GMT

Make the computer surprise you. With random colors, sizes, and positions, your art comes out different every time you press Run — the secret behind generative art.

Making Choices with if

Thu, 12 Mar 2026 00:00:00 GMT

Teach the turtle to decide. With if and else, your program can choose between options — and combined with randomness, it can surprise you in bigger ways.

Capstone: Your Own Generative Art

Mon, 16 Mar 2026 00:00:00 GMT

The big finish for Phase I. Combine functions, parameters, loops, randomness, and decisions into a one-of-a-kind generative artwork — then make it completely your own.

Talking to the Computer

Thu, 19 Mar 2026 00:00:00 GMT

Phase II begins! Put down the turtle and pick up words. Make the computer print messages, ask you questions, and remember your answers.

Working with Words

Mon, 23 Mar 2026 00:00:00 GMT

Strings are the computer's words. Glue them together, measure them, make them LOUD or quiet, and repeat them — the start of real text programs.

Numbers and Math

Thu, 26 Mar 2026 00:00:00 GMT

Make the computer your calculator: add, multiply, divide, and find remainders. Plus the big gotcha — turning the text from input() into a real number.

True or False: Asking Yes/No Questions

Mon, 30 Mar 2026 00:00:00 GMT

Before a computer can make decisions, it has to answer yes/no questions. Meet True and False, the comparison signs, and the words and, or, and not.

Making Decisions with if

Thu, 02 Apr 2026 00:00:00 GMT

Now your program can choose. Use if, elif, and else to do different things depending on the answer to a yes/no question.

Build-It Project: A Quiz Game

Mon, 06 Apr 2026 00:00:00 GMT

Put input, if, and a score together to build a real quiz game that asks questions, checks answers, keeps score, and tells the player how they did.

Repeating with while

Thu, 09 Apr 2026 00:00:00 GMT

A while loop repeats as long as something stays true. Build a countdown and a real number-guessing game that keeps asking until the player gets it right.

Lists: Holding Many Things

Mon, 13 Apr 2026 00:00:00 GMT

One variable can hold a whole collection. Meet the list — store many values, grab them by position, add new ones — the start of working with real data.

Looping Through Data

Thu, 16 Apr 2026 00:00:00 GMT

March a loop through a whole list — print every item, add them all up, count the ones you care about, find the biggest. This is what data analysis is made of.

Dictionaries: Labels for Your Data

Mon, 20 Apr 2026 00:00:00 GMT

Lists keep data in order; dictionaries label it. Store 'Ada → 90', look things up by name, and loop through labeled data — a key skill for real datasets.

Functions That Return Answers

Thu, 23 Apr 2026 00:00:00 GMT

In Phase I your functions drew shapes. Now they compute and hand back an answer with return — so you can use the result, combine it, and build real tools.

Build-It Project: A Chatbot

Mon, 27 Apr 2026 00:00:00 GMT

Build a chatbot that reads what you type and replies. Combine a while loop, keyword checks, and friendly responses into a program that holds a conversation.

Capstone: A Text Adventure

Thu, 30 Apr 2026 00:00:00 GMT

The big finish for Phase II — build a branching choose-your-own-adventure game with choices, an inventory, and multiple endings. Then get ready for Phase III.

Getting Started with Google Colab

Mon, 04 May 2026 00:00:00 GMT

Phase III moves to a real tool that professionals use: Google Colab. Here's how to get set up with an adult's help — plus free alternatives if you'd rather not use Google.

Getting Comfortable in a Notebook

Thu, 07 May 2026 00:00:00 GMT

Notebooks work a little differently from the editors you've used. Learn how cells run, how they share memory, and confirm all your Python skills work in Colab.

Meet a Real Dataset

Mon, 11 May 2026 00:00:00 GMT

Load a real table of data about Antarctic penguins with pandas, and take your first look — how many rows, what columns, and what the data actually says.

Looking Around the Data

Thu, 14 May 2026 00:00:00 GMT

Pull out exactly the columns you care about, see which values appear, and treat a column like the lists you already know. The first move of a data detective.

Filtering: Keep Only the Rows You Want

Mon, 18 May 2026 00:00:00 GMT

Ask the data questions like 'show me only the heavy penguins' or 'just the Gentoos.' Filter rows by a condition, combine conditions, and sort the results.

Counting and Grouping

Thu, 21 May 2026 00:00:00 GMT

Answer the big data questions: how many of each kind? what's the average per group? Meet value_counts and groupby — the heart of data analysis.

New Columns and Record-Holders

Mon, 25 May 2026 00:00:00 GMT

Add your own columns calculated from the data, and find the record-holders — the single heaviest penguin, the longest flipper — not just the averages.

Your First Chart

Thu, 28 May 2026 00:00:00 GMT

Turn numbers into pictures. Make bar charts from your data with one line — counts of each species, average weight per group — and actually see the story.

More Kinds of Charts

Mon, 01 Jun 2026 00:00:00 GMT

Bars aren't the only chart. Meet histograms, scatter plots, and line charts — and learn which one answers which kind of question.

Charts Anyone Can Read

Thu, 04 Jun 2026 00:00:00 GMT

A chart without labels is a mystery. Add titles, axis labels, and color, then save your chart as an image you can share.

Bring Your Own Data

Mon, 08 Jun 2026 00:00:00 GMT

The penguin skills work on any dataset. Load other built-in datasets, or any CSV from the web, and explore something you actually care about.

Capstone: A Data Detective Report

Thu, 11 Jun 2026 00:00:00 GMT

The big finish for Phase III. Pick a dataset, ask three questions, answer them with stats and charts, and write up what you discovered — a real data report.

What Is AI? Let the Computer Look at a Picture

Mon, 15 Jun 2026 00:00:00 GMT

Phase IV begins! Meet Artificial Intelligence by using one — upload a photo and watch a ready-made AI guess what's in it, in just a few lines of Python.

AI That Reads Feelings

Thu, 18 Jun 2026 00:00:00 GMT

Type a sentence and watch an AI decide whether it sounds happy or sad. Meet sentiment analysis — and start spotting where AI gets things wrong.

AI That Writes

Mon, 22 Jun 2026 00:00:00 GMT

Give an AI the start of a sentence and watch it keep going. Meet text generation — the same idea behind chatbots — and learn why it 'predicts' rather than 'thinks.'

Project: AI Explorer (and Where AI Goes Wrong)

Thu, 25 Jun 2026 00:00:00 GMT

Put all three AIs to the test with your own inputs, keep a log of the clever and the clueless, and start thinking about why AI makes the mistakes it does.

Learning From Examples

Mon, 29 Jun 2026 00:00:00 GMT

How does a computer 'learn'? The big idea behind all machine learning: instead of writing rules, you show it labeled examples and let it find the pattern.

Train Your First Model

Thu, 02 Jul 2026 00:00:00 GMT

Three lines of code, and the computer learns to tell penguin species apart from their measurements. Meet scikit-learn, fit, and predict.

Did It Actually Learn?

Mon, 06 Jul 2026 00:00:00 GMT

Testing a model on the same examples it studied is cheating. Split your data into a study set and a test set, and measure how often the model is really right.

Project: Build a Guesser

Thu, 09 Jul 2026 00:00:00 GMT

Put the whole machine-learning recipe together — load data, split it, train a model, check its accuracy, and make predictions on your own examples.

Pictures Are Just Numbers

Mon, 13 Jul 2026 00:00:00 GMT

How can a computer 'see' an image? It can't — but it can read numbers. Discover that every picture is really a grid of brightness values, setting up image AI.

Train an Image Recognizer

Thu, 16 Jul 2026 00:00:00 GMT

Teach a model to read handwritten digits. Same recipe as the penguins — but now the features are pixels, and your AI learns to recognize images.

Test It, See the Mistakes, Make It Better

Mon, 20 Jul 2026 00:00:00 GMT

A great score isn't the end. Look at the actual digits your AI got wrong, understand why, and try simple changes to push the accuracy higher.

Capstone: Teach the Computer (and Use AI Wisely)

Thu, 23 Jul 2026 00:00:00 GMT

The grand finale. Train your own model end to end, present how well it works, and have the most important conversation in AI: how to use it responsibly.

PyTorch Without the Calculus: What It Is and What You Can Ignore

Mon, 06 Apr 2026 00:00:00 GMT

A gentle, math-free introduction to PyTorch for engineers and technical PMs — what it actually is, what you can safely skip, and how to set up Google Colab to run real AI models.

Tensors: The One Data Structure You Actually Have to Like

Fri, 10 Apr 2026 00:00:00 GMT

A beginner-friendly tour of pytorch tensors — creating them, reshaping them, and moving them to the GPU — with no linear-algebra homework attached.

What a Model Really Is: A Read-Only Peek Inside the Black Box

Tue, 14 Apr 2026 00:00:00 GMT

A gentle, math-free look at what a neural network is actually made of — layers and parameters — by opening up a real PyTorch nn.Module and reading it like a spec sheet. Beginner-friendly.

Your First Real Model Run, From Photo to Verdict

Sat, 18 Apr 2026 00:00:00 GMT

A beginner-friendly walkthrough to run a pretrained model in PyTorch end to end — download an image and do image classification with torchvision, no deep-learning math required.

Logits, Softmax, and the Two Ends of Every Model

Wed, 22 Apr 2026 00:00:00 GMT

A beginner-friendly guide to PyTorch model inputs and outputs — preprocessing and batch dimensions on one end, logits vs probabilities on the other — so you can run any pretrained model with confidence.

Three Lines and a Verdict: Running Models with Hugging Face Pipelines

Sun, 26 Apr 2026 00:00:00 GMT

A beginner-friendly tour of the Hugging Face transformers pipeline — the fastest way to run a pretrained model in three lines, across text, images, and audio.

Beyond pipeline(): Taking the Wheel with from_pretrained

Thu, 30 Apr 2026 00:00:00 GMT

A beginner-friendly guide to dropping below pipeline() for control — using AutoTokenizer and AutoModel from_pretrained, a huggingface tokenizer, and reading raw logits by hand.

The Hub and the Heavyweights: Finding Models and Running Big Ones Without Melting Your Laptop

Mon, 04 May 2026 00:00:00 GMT

A beginner-friendly guide to the Hugging Face Hub — how to find the right model and read its card and license — plus how to run large models with quantization so they fit on a free Colab GPU.

From Notebook to App: Wrap a Model in a UI Anyone Can Use

Fri, 08 May 2026 00:00:00 GMT

Build an AI app in PyTorch by wrapping a pretrained model in a Gradio app — a beginner-friendly capstone that turns a model into a real, shareable little tool.

How a Model Learns: Being Wrong, On Purpose, A Million Times

Tue, 12 May 2026 00:00:00 GMT

A math-free, beginner-friendly walkthrough of how neural networks learn — the training intuition behind loss, gradients, optimizers, and epochs, with no calculus required.

The Five-Line Training Loop That Makes PyTorch Learn

Sat, 16 May 2026 00:00:00 GMT

A beginner-friendly walk through the PyTorch training loop — forward, loss, backward, optimizer step — and what loss.backward() and optimizer.step() actually do.

Datasets and DataLoaders: Feeding the Beast Without Choking It

Wed, 20 May 2026 00:00:00 GMT

A beginner-friendly guide to the PyTorch Dataset and DataLoader — how batching data and shuffling feed your training loop the right way, with a tiny custom example.

Transfer Learning: Standing on a Pretrained Model's Shoulders

Sun, 24 May 2026 00:00:00 GMT

A beginner-friendly guide to transfer learning in PyTorch — fine-tune a pretrained model by swapping its head and freezing the backbone, no training-from-scratch required.

Fine-Tuning the Lazy Way: Let the Trainer Run Your Loop

Thu, 28 May 2026 00:00:00 GMT

A beginner-friendly walkthrough of huggingface Trainer fine-tuning — fine-tune a text classifier on a real dataset end to end, with the hand-written training loop done for you.

Did Your Model Actually Learn Anything? Evaluating Honestly

Mon, 01 Jun 2026 00:00:00 GMT

A beginner-friendly guide to evaluating a machine learning model — train/validation/test splits, accuracy, precision/recall and F1, and spotting overfitting before it fools you.

LoRA: Fine-Tune a Giant Model on a Free GPU

Fri, 05 Jun 2026 00:00:00 GMT

A beginner-friendly guide to LoRA fine-tuning and PEFT (parameter-efficient fine-tuning) — freeze the big model, train tiny adapters, and ship megabytes instead of gigabytes.

When Not to Fine-Tune: The Cheaper Things to Try First

Tue, 09 Jun 2026 00:00:00 GMT

A beginner-friendly guide to when to fine-tune vs prompting vs RAG — why fine-tuning is usually the wrong first move, and the faster, cheaper options to reach for before it.

The Capstone: Fine-Tune a Model and Put It on the Hub

Sat, 13 Jun 2026 00:00:00 GMT

A beginner-friendly capstone — fine-tune a text classifier with the Trainer, then push to Hugging Face Hub and load it straight back to prove it's a real, shareable model.