Implementation:Vespa engine Vespa ApplicationId

Knowledge Sources	Vespa Vespa Cloud API
Domains	Cloud_API, Application_Identity
Last Updated	2026-02-09 00:00 GMT

Overview

Immutable value object representing the identity of a Vespa application as a combination of tenant, application, and instance names.

Description

The ApplicationId class is part of the Vespa Cloud public API (ai.vespa.cloud package). It encapsulates the three-part identity of a deployed Vespa application: tenant name, application name, and instance name. This is the fundamental identity primitive used throughout the Vespa Cloud platform to identify which application and instance the code is running as.

The class provides:

• Immutable construction from three string components
• Accessor methods for each component
• Proper equals/hashCode for use in collections
• A toString format of "tenant.application.instance"

Usage

Use this class when you need to programmatically identify which Vespa application you are running in. It is typically obtained via SystemInfo injection in a Vespa Cloud environment, not constructed directly by application code.

Code Reference

Source Location

• Repository: Vespa
• File: hosted-zone-api/src/main/java/ai/vespa/cloud/ApplicationId.java
• Lines: 1-45

Signature

public class ApplicationId {

    public ApplicationId(String tenant, String application, String instance)

    public String tenant()
    public String application()
    public String instance()

    @Override public boolean equals(Object o)
    @Override public int hashCode()
    /** Returns the string tenant.application.instance */
    @Override public String toString()
}

Import

import ai.vespa.cloud.ApplicationId;

I/O Contract

Inputs

Name	Type	Required	Description
tenant	String	Yes	The tenant name
application	String	Yes	The application name
instance	String	Yes	The instance name

Outputs

Name	Type	Description
tenant()	String	The tenant component of the identity
application()	String	The application component of the identity
instance()	String	The instance component of the identity
toString()	String	Format: "tenant.application.instance"

Usage Examples

Accessing Application Identity

import ai.vespa.cloud.ApplicationId;
import ai.vespa.cloud.SystemInfo;
import com.yahoo.component.annotation.Inject;

public class MyHandler {

    private final ApplicationId appId;

    @Inject
    public MyHandler(SystemInfo systemInfo) {
        this.appId = systemInfo.application();
    }

    public String getTenantName() {
        return appId.tenant();
    }

    public String getFullId() {
        // Returns "myTenant.myApp.default"
        return appId.toString();
    }
}

Related Pages

• Principle:Vespa_engine_Vespa_Cloud_Deployment_Context