Packages 
Package Description
org.activiti.engine
Public API of the Activiti engine.

Typical usage of the API starts by the creation of a ProcessEngineConfiguration (typically based on a configuration file), from which a ProcessEngine can be obtained.

Through the services obtained from such a ProcessEngine, BPM and workflow operation can be executed:

RepositoryService: Manages Deployments
RuntimeService: For starting and searching ProcessInstances
TaskService: Exposes operations to manage human (standalone) Tasks, such as claiming, completing and assigning tasks
org.activiti.engine.IdentityService: Used for managing org.activiti.engine.identity.Users, org.activiti.engine.identity.Groups and the relations between them
ManagementService: Exposes engine admin and maintenance operations, which have no relation to the runtime exection of business processes
HistoryService: Exposes information about ongoing and past process instances.
org.activiti.engine.FormService: Access to form data and rendered forms for starting new process instances and completing tasks.
org.activiti.engine.api.internal  
org.activiti.engine.cfg  
org.activiti.engine.cfg.security  
org.activiti.engine.debug  
org.activiti.engine.delegate
Interfaces used to include Java code in a process as the behavior of an activity or as a listener to process events with JavaDelegates.
org.activiti.engine.delegate.event  
org.activiti.engine.delegate.event.impl  
org.activiti.engine.event  
org.activiti.engine.history
Classes related to the HistoryService.
org.activiti.engine.impl
API implementation classes, which shouldn't directly be used by end-users.
org.activiti.engine.impl.agenda  
org.activiti.engine.impl.asyncexecutor  
org.activiti.engine.impl.asyncexecutor.multitenant  
org.activiti.engine.impl.bpmn.behavior  
org.activiti.engine.impl.bpmn.data  
org.activiti.engine.impl.bpmn.deployer  
org.activiti.engine.impl.bpmn.diagram  
org.activiti.engine.impl.bpmn.helper  
org.activiti.engine.impl.bpmn.listener  
org.activiti.engine.impl.bpmn.parser  
org.activiti.engine.impl.bpmn.parser.factory  
org.activiti.engine.impl.bpmn.parser.handler  
org.activiti.engine.impl.bpmn.webservice  
org.activiti.engine.impl.calendar  
org.activiti.engine.impl.cfg  
org.activiti.engine.impl.cfg.jta  
org.activiti.engine.impl.cfg.multitenant  
org.activiti.engine.impl.cfg.standalone  
org.activiti.engine.impl.cmd  
org.activiti.engine.impl.cmd.integration  
org.activiti.engine.impl.context  
org.activiti.engine.impl.db  
org.activiti.engine.impl.db.upgrade  
org.activiti.engine.impl.delegate  
org.activiti.engine.impl.delegate.invocation  
org.activiti.engine.impl.el  
org.activiti.engine.impl.event  
org.activiti.engine.impl.event.logger  
org.activiti.engine.impl.event.logger.handler  
org.activiti.engine.impl.history  
org.activiti.engine.impl.identity  
org.activiti.engine.impl.interceptor  
org.activiti.engine.impl.jobexecutor  
org.activiti.engine.impl.json
Experimental: contains helpers to serialize all return values from the services into JSON.
org.activiti.engine.impl.persistence  
org.activiti.engine.impl.persistence.cache  
org.activiti.engine.impl.persistence.deploy  
org.activiti.engine.impl.persistence.entity  
org.activiti.engine.impl.persistence.entity.data  
org.activiti.engine.impl.persistence.entity.data.impl  
org.activiti.engine.impl.persistence.entity.data.impl.cachematcher  
org.activiti.engine.impl.persistence.entity.data.impl.util  
org.activiti.engine.impl.persistence.entity.data.integration  
org.activiti.engine.impl.persistence.entity.integration  
org.activiti.engine.impl.repository  
org.activiti.engine.impl.runtime  
org.activiti.engine.impl.scripting  
org.activiti.engine.impl.test  
org.activiti.engine.impl.transformer  
org.activiti.engine.impl.util  
org.activiti.engine.impl.util.condition  
org.activiti.engine.impl.util.io  
org.activiti.engine.impl.util.json  
org.activiti.engine.impl.variable  
org.activiti.engine.impl.webservice  
org.activiti.engine.integration  
org.activiti.engine.logging  
org.activiti.engine.management
Classes related to the ManagementService.
org.activiti.engine.parse  
org.activiti.engine.query
Classes related to the querying entities in the engine.
org.activiti.engine.repository
Classes related to the RepositoryService.
org.activiti.engine.runtime
Classes related to the RuntimeService.
org.activiti.engine.task
Classes related to the TaskService.
org.activiti.engine.test
Helper classes for testing processes.
org.activiti.engine.test.impl.logger  
org.activiti.engine.test.mock  
org.activiti.engine.test.profiler