Incremental Tasks & Up-to-Date Checks
Make custom tasks fast and correct by declaring inputs and outputs so Gradle can skip work that is already up to date.
Incremental Tasks & Up-to-Date Checks is a free Groovy & Gradle: JVM Automation and Build Engineering lesson on CoddyKit — lesson 4 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Groovy & Gradle: JVM Automation and Build Engineering learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Why Tasks Get Skipped
Gradle is fast because it does not redo work. If a task ran before and nothing it depends on changed, Gradle marks it UP-TO-DATE and skips it. You enable this by declaring inputs and outputs.
Inputs and Outputs
Every task can declare what it reads (inputs) and what it produces (outputs). Gradle hashes them to decide whether to run.
Declaring File Inputs
Annotate or register input files so Gradle watches them for changes.
tasks.register('process') {
inputs.file 'data/in.txt'
outputs.file 'build/out.txt'
}The Up-to-Date Decision
On each run Gradle compares current input/output hashes to the last run. If both match, the task is skipped; if any input changed, it re-runs.
Property Inputs
Non-file inputs (a flag, a version string) are declared with inputs.property so changing them also invalidates the cache.
tasks.register('gen') {
inputs.property 'version', project.version
outputs.dir 'build/gen'
}Custom Task Types
For reusable logic, write a task class with annotated properties: @InputFile, @OutputFile, @Input. Gradle reads the annotations automatically.
An Annotated Task Class
Annotations tell Gradle how to track each property without manual inputs/outputs wiring.
class Copy extends DefaultTask {
@InputFile File source
@OutputFile File dest
@TaskAction void run() { dest.text = source.text }
}Incremental Inputs
For tasks over many files, @Incremental inputs let the action process only the files that actually changed since last run.
The Build Cache
Beyond up-to-date checks, the build cache can reuse outputs from a previous run on any machine, keyed by the same input hashes — huge for CI.
org.gradle.caching=trueCommon Mistakes
Forgetting to declare an input is the classic bug: Gradle skips a task that should have re-run, producing stale output. Always declare every input that affects the result.
Forcing a Rerun
To verify caching or work around a stale state, run with --rerun-tasks to ignore up-to-date checks for one build, or use outputs.upToDateWhen { false } to mark a task as never up to date.
gradle build --rerun-tasksQuick Check
Test your incremental build knowledge.
Recap
You learned to build fast, correct tasks:
- Gradle skips tasks whose inputs and outputs are unchanged
- Declare files with
inputs.file/outputs.fileand values withinputs.property - Custom task classes use
@InputFile/@OutputFileannotations - The build cache reuses outputs across machines
- Undeclared inputs cause stale, incorrect skips
Frequently asked questions
Is the “Incremental Tasks & Up-to-Date Checks” lesson free?
Yes — the full text of “Incremental Tasks & Up-to-Date Checks” is free to read here on the web, and the Groovy & Gradle: JVM Automation and Build Engineering course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Groovy & Gradle: JVM Automation and Build Engineering course, upgrade to CoddyKit PRO.
What will I learn in “Incremental Tasks & Up-to-Date Checks”?
Make custom tasks fast and correct by declaring inputs and outputs so Gradle can skip work that is already up to date. You practise Groovy & Gradle: JVM Automation and Build Engineering with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Groovy & Gradle: JVM Automation and Build Engineering?
No prior experience is required. Groovy & Gradle: JVM Automation and Build Engineering on CoddyKit is structured for beginners through advanced learners; this is — lesson 4 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Incremental Tasks & Up-to-Date Checks” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Groovy & Gradle: JVM Automation and Build Engineering lesson?
Yes. Every Groovy & Gradle: JVM Automation and Build Engineering lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Defining Custom Tasks
- Task Types & Actions
- Task Properties & Configuration
- Incremental Tasks & Up-to-Date Checks