* Add Java SDK reference files (11 files) Create complete Java reference documentation covering: - java.md: Entry point with quick start tutorial, key concepts - patterns.md: 17 patterns (signals, queries, updates, child workflows, saga, cancellation scopes, heartbeating, etc.) - determinism.md: Safe alternatives table, forbidden operations - determinism-protection.md: Convention-based enforcement (no sandbox) - error-handling.md: ApplicationFailure, retry/timeout config - gotchas.md: Non-deterministic operations, cancellation, heartbeating - testing.md: TestWorkflowEnvironment, Mockito mocking, replay testing - versioning.md: Workflow.getVersion(), worker versioning - data-handling.md: Jackson, PayloadConverter, encryption, search attributes - observability.md: SLF4J logging, Micrometer metrics - advanced-features.md: Schedules, async completion, worker tuning Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * Fix Java alignment issues from self-review - Reduce gotchas.md Non-Deterministic Operations from ~94 lines to ~12 (reference determinism.md instead of duplicating) - Remove Workflow Failure Exception Types duplication from error-handling.md (keep only in advanced-features.md) - Expand versioning.md Worker Versioning with Key Concepts, PINNED vs AUTO_UPGRADE, Deployment Strategies subsections - Fix section names to match Python reference style: Activity Heartbeat Details, Handling Activity Errors, Retry Policy Configuration, Workflow Test Environment, Mocking Activities, Workflow Replay Testing - Reduce data-handling.md Payload Encryption verbosity - Reduce observability.md Logger Customization verbosity - Reduce testing.md to single approach per section - Rename determinism.md "Convention-Based Enforcement" to "SDK Protection" - Fix handler guidance in patterns.md to match Python Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * Fix correctness issues in Java reference files - patterns.md: Fix Queries section — ActivityStub → typed interface (Workflow.newActivityStub returns the typed interface, not ActivityStub) - data-handling.md: Add missing ProtobufPayloadConverter to default converter chain (4th of 5 converters) Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * Add Java to SKILL.md and core/determinism.md - SKILL.md: Add "Temporal Java" trigger phrase, update Overview to list Java, add Java entry to Getting Started references - core/determinism.md: Add Java entry to SDK Protection Mechanisms (no sandbox, convention-based, NonDeterministicException at replay) Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * Apply manual editorial fixes to Java references - java.md: Remove "Understanding Replay" section (covered by Overview), simplify File Organization note (no sandbox rationale) - gotchas.md: Move Heartbeating before Cancellation, make Wrong Retry Classification brief with reference (not inline examples) - error-handling.md: Remove editorializing from Workflow Failure note - determinism-protection.md: Remove cross-language comparison paragraph (state Java's approach on its own terms) Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * Add temporal-workflowcheck static analysis to Java determinism docs - determinism-protection.md: Add "Static Analysis with temporal-workflowcheck" section with Gradle/Maven setup, manual run, and suppression instructions. Beta warning included. - determinism.md: Update overview and SDK Protection to reference workflowcheck - core/determinism.md: Update Java entry in SDK Protection Mechanisms Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * Integrate feedback from Go PR into Java patterns - Updates: Add validator note — validators must not mutate state or block (matches note added to Python, TypeScript, Go, and core) - Saga Pattern: Use Workflow.newDetachedCancellationScope() for compensations so they execute even if the workflow is cancelled (mirrors Go's workflow.NewDisconnectedContext pattern) Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com> * docs: add @WorkflowInit description to java.md Key Concepts Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> * mark java as supported * Apply suggestions from code review Co-authored-by: Brian Strauch <brian@brianstrauch.com> * strongly recommend java 21+ * Softened stance on static checker and replay testing. * address python/typescript sandboxing comment --------- Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Co-authored-by: Brian Strauch <brian.strauch@temporal.io> Co-authored-by: Brian Strauch <brian@brianstrauch.com>
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Java SDK Versioning
For conceptual overview and guidance on choosing an approach, see references/core/versioning.md.
Patching API
Workflow.getVersion()
Workflow.getVersion(String changeId, int minSupported, int maxSupported) returns the version to use for a given change:
import io.temporal.workflow.Workflow;
@WorkflowInterface
public interface ShippingWorkflow {
@WorkflowMethod
void run();
}
public class ShippingWorkflowImpl implements ShippingWorkflow {
@Override
public void run() {
int version = Workflow.getVersion(
"send-email-instead-of-fax",
Workflow.DEFAULT_VERSION, // minSupported (no change)
1 // maxSupported (current version)
);
if (version == 1) {
// New code path
Workflow.newActivityStub(MyActivities.class, options).sendEmail();
} else {
// Old code path (for replay of existing workflows)
Workflow.newActivityStub(MyActivities.class, options).sendFax();
}
}
}
How it works:
- For new executions: returns
maxSupportedand records a marker in history - For replay with the marker: returns the recorded version
- For replay without the marker: returns
DEFAULT_VERSION(-1)
Three-Step Patching Process
Step 1: Patch in New Code
Add the version check with both old and new code paths:
public class OrderWorkflowImpl implements OrderWorkflow {
@Override
public String run(Order order) {
int version = Workflow.getVersion(
"add-fraud-check",
Workflow.DEFAULT_VERSION,
1);
if (version >= 1) {
activities.checkFraud(order);
}
return activities.processPayment(order);
}
}
Step 2: Remove Old Code Path
Once all pre-patch Workflow Executions have completed, remove the old branch and set minSupported to 1:
public class OrderWorkflowImpl implements OrderWorkflow {
@Override
public String run(Order order) {
Workflow.getVersion("add-fraud-check", 1, 1);
activities.checkFraud(order);
return activities.processPayment(order);
}
}
Step 3: Remove the Patch
After all workflows with the patch marker have completed, remove the getVersion call entirely:
public class OrderWorkflowImpl implements OrderWorkflow {
@Override
public String run(Order order) {
activities.checkFraud(order);
return activities.processPayment(order);
}
}
Recording TemporalChangeVersion Search Attribute
Unlike the Python and TypeScript SDKs, the Java SDK does not automatically record the TemporalChangeVersion search attribute. You must manually upsert it:
import io.temporal.workflow.Workflow;
import io.temporal.common.SearchAttributeKey;
import java.util.List;
public class OrderWorkflowImpl implements OrderWorkflow {
private static final SearchAttributeKey<List<String>> TEMPORAL_CHANGE_VERSION =
SearchAttributeKey.forKeywordList("TemporalChangeVersion");
@Override
public String run(Order order) {
int version = Workflow.getVersion("add-fraud-check", Workflow.DEFAULT_VERSION, 1);
// Manually record for query filtering
Workflow.upsertTypedSearchAttributes(
TEMPORAL_CHANGE_VERSION.valueSet(List.of("add-fraud-check-1")));
if (version >= 1) {
activities.checkFraud(order);
}
return activities.processPayment(order);
}
}
Query with:
temporal workflow list --query \
'TemporalChangeVersion = "add-fraud-check-1" AND ExecutionStatus = "Running"'
Workflow Type Versioning
For incompatible changes, create a new Workflow Type:
@WorkflowInterface
public interface PizzaWorkflow {
@WorkflowMethod
String run(PizzaOrder order);
}
// Original implementation
public class PizzaWorkflowImpl implements PizzaWorkflow {
@Override
public String run(PizzaOrder order) {
return processOrderV1(order);
}
}
// New workflow type for incompatible changes
@WorkflowInterface
public interface PizzaWorkflowV2 {
@WorkflowMethod
String run(PizzaOrder order);
}
public class PizzaWorkflowV2Impl implements PizzaWorkflowV2 {
@Override
public String run(PizzaOrder order) {
return processOrderV2(order);
}
}
Register both with the Worker:
worker.registerWorkflowImplementationTypes(
PizzaWorkflowImpl.class,
PizzaWorkflowV2Impl.class);
Start new workflows with the new type:
PizzaWorkflowV2 workflow = client.newWorkflowStub(
PizzaWorkflowV2.class,
WorkflowOptions.newBuilder()
.setTaskQueue("pizza-task-queue")
.build());
workflow.run(order);
Check for open executions before removing the old type:
temporal workflow list --query 'WorkflowType = "PizzaWorkflow" AND ExecutionStatus = "Running"'
Worker Versioning
Worker Versioning manages versions at the deployment level. Available since Java SDK v1.29.
Key Concepts
- Worker Deployment: A logical group of Workers processing the same Task Queue, identified by a deployment name (e.g.,
"order-service"). - Worker Deployment Version: A specific version within a deployment, identified by the combination of deployment name and Build ID (e.g.,
"order-service:v1.0.0"). Each version corresponds to a particular code revision.
Configuring Workers
import io.temporal.worker.Worker;
import io.temporal.worker.WorkerFactory;
import io.temporal.worker.WorkerOptions;
import io.temporal.worker.WorkerDeploymentOptions;
import io.temporal.worker.WorkerDeploymentVersion;
WorkerDeploymentVersion version = WorkerDeploymentVersion.newBuilder()
.setDeploymentName("order-service")
.setBuildId("v1.0.0") // or git commit hash
.build();
WorkerDeploymentOptions deploymentOptions = WorkerDeploymentOptions.newBuilder()
.setVersion(version)
.setUseWorkerVersioning(true)
.build();
WorkerFactory factory = WorkerFactory.newInstance(client);
Worker worker = factory.newWorker(
"my-task-queue",
WorkerOptions.newBuilder()
.setDeploymentOptions(deploymentOptions)
.build());
worker.registerWorkflowImplementationTypes(MyWorkflowImpl.class);
worker.registerActivitiesImplementations(new MyActivitiesImpl());
factory.start();
PINNED vs AUTO_UPGRADE Behaviors
Set the versioning behavior on the workflow definition:
import io.temporal.workflow.VersioningBehavior;
import io.temporal.workflow.Workflow;
public class MyWorkflowImpl implements MyWorkflow {
@Override
public String run(String input) {
Workflow.setVersioningBehavior(VersioningBehavior.PINNED);
// ... workflow logic
}
}
PINNED: Workflow stays on the Worker version that started it. Use for short-running workflows or when consistency within a single execution is critical. New workflows start on the current version; existing ones stay put.
AUTO_UPGRADE: Workflow moves to the latest Worker version on the next Workflow Task. Use for long-running workflows that need bug fixes or feature updates. Combine with Workflow.getVersion() patching to handle version transitions safely.
Deployment Strategies
Blue-Green: Run two deployment versions simultaneously. Set the new version as the current deployment. PINNED workflows finish on the old version; new workflows start on the new version. Drain the old version once all its workflows complete.
Rainbow: Run multiple versions concurrently for gradual rollouts. Each version handles its own workflows. Useful when you have many long-running PINNED workflows across several code revisions.
Querying Workflows by Worker Version
# List workflows running on a specific version
temporal workflow list --query \
'TemporalWorkerDeploymentVersion = "order-service:v1.0.0" AND ExecutionStatus = "Running"'
# Count workflows per version to monitor drain progress
temporal workflow count --query \
'TemporalWorkerDeploymentVersion = "order-service:v1.0.0" AND ExecutionStatus = "Running"'
Best Practices
- Check for open executions before removing old code paths
- Use descriptive change IDs that explain the change (e.g.,
"add-fraud-check"not"patch-1") - Deploy patches incrementally: patch, remove old path, remove
getVersion - Manually upsert
TemporalChangeVersionsearch attribute when usinggetVersionif you need query filtering - Use PINNED for short workflows to simplify version management
- Use AUTO_UPGRADE with patching for long-running workflows that need updates
- Generate Build IDs from code (git hash) to ensure changes produce new versions