To build GAX:
# Go to the repository root
cd gapic-generator-java
# Install dependency modules to local Maven repository. Note that
# gapic-generator-java module is not a dependency of gax-java
mvn -pl '!gapic-generator-java,!gax-java' install -DskipTests
# Build and install gax-java
mvn clean install -f gax-javaTo see the effect of GAX changes in local gapic-generator-java invocation, see "Running the Plugin under googleapis with local gapic-generator-java" in gapic-generator-java/DEVELOPMENT.md