Protocol Buffers - Google’s data interchange format

Copyright 2008 Google Inc.

The Protobuf Java Lite Runtime

The Protobuf Java Lite runtime is a separate runtime designed to be used on mobile clients (especially on Android).

Lite runtime should not be used on server-side, as the tradeoffs it makes are not suited for that environment. In server contexts, the Full runtime should always be used instead.

The design goals differ from the Full runtime, focused on small binary size and lower peak memory usage. To achieve this it takes a number of trade-offs, including:

  • Offers a subset of features (including no reflection, ProtoJSON or TextProto support).

  • It may have slower runtime performance characteristics.

  • It may be less hardened against certain issues that could be a concern on server-side if they wouldn’t be a concern in the context of mobile clients.

  • In order to achieve maximum performance and code size, we do NOT guarantee API/ABI stability for Java Lite.

If these trade-offs are not acceptable for your use-case, use the full Java runtime instead.

You can generate Java Lite code for your .proto files:

$ protoc --java_out=lite:${OUTPUT_DIR} path/to/your/proto/file

Include the generated Java files in your project and add a dependency on the protobuf Java Lite runtime. If you are using Maven, include the following:

<dependency>
  <groupId>com.google.protobuf</groupId>
  <artifactId>protobuf-javalite</artifactId>
  <version><!--version--></version>
</dependency>

And replace <!--version--> with a version from the Maven Protocol Buffers [Lite] Repository. For example, 3.25.3.

R8 rule to make production app builds work

The Lite runtime internally uses reflection to avoid generating hashCode/equals/parse/serialize methods. R8 by default obfuscates the field names, which makes the reflection fail causing exceptions of the form java.lang.RuntimeException: Field {NAME}_ for {CLASS} not found. Known fields are [ {FIELDS} ] in MessageSchema.java.

See previous discussion about this on the protobuf Github project and R8.

In some cases, you may need to create a proguard-rules.pro file to mitigate the obfuscation breaking the reflective codepaths, for example:

-keep class * extends com.google.protobuf.GeneratedMessageLite { *; }