Pulsar uses protocol buffer messages for the client/broker wire protocol.
The protocol definition is located at pulsar-common/src/main/proto/PulsarApi.proto and the pre-generated Java code is at pulsar-common/src/main/java/com/yahoo/pulsar/common/api/proto/PulsarApi.java.
When making a change to the PulsarApi.proto definition, we have regenerate the PulsarApi.java and include that in the same commit.
We are currently using a modified version of the Google Protocol Buffer code generator, to generate code that can serialize/deserialize messages with no memory allocations (caching already instantiated objects) and also to be able to directly use Netty pooled ByteBuf with direct memory.
To re-generate the PulsarApi.java code you need to apply a patch to the protobuf generator. Patch is found at protobuf.patch.
git clone https://github.com/google/protobuf.git
cd protobuf
git checkout v2.4.1
# Apply patch
patch -p1 < ../pulsar-path/protobuf/protobuf.patch
# Compile protobuf
./configure
make
# This would leave the binary in src/protoc
# Re-generate PulsarApi
cd pulsar-path/pulsar-common
PROTOC=~/protobuf/src/protoc ./generate_protobuf.sh