Currently as of RHPAM/RHDM 7.12, RHPAM/RHDM supports several classes of KIE Server Java Client API [1]. The current product documentation [1] guides users to reference source code of those interface classes, but the source code does not provide any detail descriptions/explanations on almost all methods and parameters of those classes.
API reference document (at least javadoc) for KIE Server Java Client API should be provided.

[1] Red Hat Process Automation Manager > 7.12 > Deploying and managing Red Hat Process Automation Manager services - 22.2. Supported KIE Server Java clients
https://access.redhat.com/documentation/en-us/red_hat_process_automation_manager/7.12/html-single/deploying_and_managing_red_hat_process_automation_manager_services/index#kie-server-java-clients-ref_kie-apis

For the full list of available KIE Server Java clients, download the Red Hat Process Automation Manager 7.12.0 Source Distribution from the Red Hat Customer Portal and navigate to ~/rhpam-7.12.0-sources/src/droolsjbpm-integration-$VERSION/kie-server-parent/kie-server-remote/kie-server-client/src/main/java/org/kie/server/client.

In the document [1], currently supported client classes are the following. Details of these classes should be documented at least.

• KieServicesClient: Used as the entry point for other KIE Server Java clients, and used to interact with KIE containers
• JobServicesClient: Used to schedule, cancel, re-queue, and get job requests
• RuleServicesClient: Used to send commands to the server to perform rule-related operations, such as executing rules or inserting objects into the KIE session
• SolverServicesClient: Used to perform all Red Hat build of OptaPlanner operations, such as getting the solver state and the best solution, or disposing a solver
• ProcessServicesClient: Used to start, signal, and abort processes or work items
• QueryServicesClient: Used to query processes, process nodes, and process variables
• UserTaskServicesClient: Used to perform all user-task operations, such as starting, claiming, or canceling a task, and to query tasks by a specified field, such as by user or by process instances ID
• UIServicesClient: Used to get String representation of forms (XML or JSON) and of a process image (SVG)
• ProcessAdminServicesClient: Provides an interface for operations with process instances (found in ~/org/kie/server/client/admin)
• UserTaskAdminServicesClient: Provides an interface for operations with user tasks (found in ~/org/kie/server/client/admin)

The following class does not exist in the list above, but REST endpoints corresponding to the class are available in KIE Server REST API, so details for the class should also be documented.

• DocumentServicesClient

Also, to actually develop using KIE Server Java Client API, descriptions of the following class are essential and should also be documented.

• KieServicesConfiguration

For each class, the following descriptions should be documented.

• Descriptions of the class.
• Descriptions for each public/supported method.
• Descriptions for each parameter.
• How to create or prepare for a parameter with complex data type, e.g. List, Map, another class etc.
• What data returns for each method.
• Descriptions for each class/enum which is used as a parameter type, e.g. KieContainerResource, TaskSummary, etc.