The Java Real-Time Optimized (RTO) messaging API (also referred to as solclientj) is a low-latency Java Native Interface (JNI) wrapper for the C API.

Message Exchange Patterns

The Java RTO API supports all common message exchange patterns.

  • Publish / Subscribe
  • Point-to-Point
  • Request / Reply

For more information, see Message Exchange Patterns.


The Java RTO API supports all common API features.

  • Connection management to Solace PubSub+ event brokers
  • Addition and removal of topic subscriptions
  • Sending and receiving Direct and Guaranteed messages
  • Extensive support for logging and customizing through property parameters
  • Request / Reply messaging support
  • Session Transactions
  • PubSub+ Cache Client API support
  • Queue browsing
  • Message Replay
  • Topic dispatch
  • Provisioning of durable endpoints

The Java RTO API does not currently support the following features:

  • XA Transactions

Get Started

Tutorials are provided to help you quickly get up to speed developing applications using the Solace Java RTO messaging API. There are three ways you can get started:

  1. If you have Solace PubSub+ event brokers already deployed, obtain the hostname, or IP address, of an event broker to test against, a username and password to access it, and a Message VPN in which you can produce and consume messages.
  2. You can go through an Initial Set Up of a software event broker.
  3. You can spin up Solace PubSub+ Cloud.

Start Tutorials

Java RTO API Reference

Click below to access the API Reference Help for the Solace Java RTO API.

Java RTO Reference

Java RTO API Release Notes

Click below to download the latest release notes for the Solace Java RTO API.

Java RTO API Release Notes