diff --git a/java-eventarc-publishing/README.md b/java-eventarc-publishing/README.md
index 7bdd950f4d48..fe444e007a5a 100644
--- a/java-eventarc-publishing/README.md
+++ b/java-eventarc-publishing/README.md
@@ -22,20 +22,20 @@ If you are using Maven, add this to your pom.xml file:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-eventarc-publishing</artifactId>
-  <version>0.3.5</version>
+  <version>0.3.6</version>
 </dependency>
 ```
 
 If you are using Gradle without BOM, add this to your dependencies:
 
 ```Groovy
-implementation 'com.google.cloud:google-cloud-eventarc-publishing:0.3.5'
+implementation 'com.google.cloud:google-cloud-eventarc-publishing:0.3.6'
 ```
 
 If you are using SBT, add this to your dependencies:
 
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-eventarc-publishing" % "0.3.5"
+libraryDependencies += "com.google.cloud" % "google-cloud-eventarc-publishing" % "0.3.6"
 ```
 
 ## Authentication
diff --git a/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishChannelConnectionEventsRequest.java b/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishChannelConnectionEventsRequest.java
index efe8b8595694..c6357554e3a7 100644
--- a/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishChannelConnectionEventsRequest.java
+++ b/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishChannelConnectionEventsRequest.java
@@ -55,65 +55,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private PublishChannelConnectionEventsRequest(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    int mutable_bitField0_ = 0;
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              channelConnection_ = s;
-              break;
-            }
-          case 18:
-            {
-              if (!((mutable_bitField0_ & 0x00000001) != 0)) {
-                events_ = new java.util.ArrayList<com.google.protobuf.Any>();
-                mutable_bitField0_ |= 0x00000001;
-              }
-              events_.add(input.readMessage(com.google.protobuf.Any.parser(), extensionRegistry));
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      if (((mutable_bitField0_ & 0x00000001) != 0)) {
-        events_ = java.util.Collections.unmodifiableList(events_);
-      }
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.eventarc.publishing.v1.PublisherProto
         .internal_static_google_cloud_eventarc_publishing_v1_PublishChannelConnectionEventsRequest_descriptor;
@@ -269,7 +210,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     for (int i = 0; i < events_.size(); i++) {
       output.writeMessage(2, events_.get(i));
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -284,7 +225,7 @@ public int getSerializedSize() {
     for (int i = 0; i < events_.size(); i++) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(2, events_.get(i));
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -303,7 +244,7 @@ public boolean equals(final java.lang.Object obj) {
 
     if (!getChannelConnection().equals(other.getChannelConnection())) return false;
     if (!getEventsList().equals(other.getEventsList())) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -320,7 +261,7 @@ public int hashCode() {
       hash = (37 * hash) + EVENTS_FIELD_NUMBER;
       hash = (53 * hash) + getEventsList().hashCode();
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -458,19 +399,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
 
     // Construct using
     // com.google.cloud.eventarc.publishing.v1.PublishChannelConnectionEventsRequest.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {
-        getEventsFieldBuilder();
-      }
     }
 
     @java.lang.Override
@@ -480,10 +412,11 @@ public Builder clear() {
 
       if (eventsBuilder_ == null) {
         events_ = java.util.Collections.emptyList();
-        bitField0_ = (bitField0_ & ~0x00000001);
       } else {
+        events_ = null;
         eventsBuilder_.clear();
       }
+      bitField0_ = (bitField0_ & ~0x00000001);
       return this;
     }
 
@@ -612,7 +545,7 @@ public Builder mergeFrom(
           }
         }
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -627,20 +560,49 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.eventarc.publishing.v1.PublishChannelConnectionEventsRequest parsedMessage =
-          null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                channelConnection_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 10
+            case 18:
+              {
+                com.google.protobuf.Any m =
+                    input.readMessage(com.google.protobuf.Any.parser(), extensionRegistry);
+                if (eventsBuilder_ == null) {
+                  ensureEventsIsMutable();
+                  events_.add(m);
+                } else {
+                  eventsBuilder_.addMessage(m);
+                }
+                break;
+              } // case 18
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.eventarc.publishing.v1.PublishChannelConnectionEventsRequest)
-                e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1134,7 +1096,18 @@ public PublishChannelConnectionEventsRequest parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new PublishChannelConnectionEventsRequest(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishChannelConnectionEventsResponse.java b/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishChannelConnectionEventsResponse.java
index 5cbd4532313c..d88348ff4430 100644
--- a/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishChannelConnectionEventsResponse.java
+++ b/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishChannelConnectionEventsResponse.java
@@ -52,45 +52,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private PublishChannelConnectionEventsResponse(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.eventarc.publishing.v1.PublisherProto
         .internal_static_google_cloud_eventarc_publishing_v1_PublishChannelConnectionEventsResponse_descriptor;
@@ -121,7 +82,7 @@ public final boolean isInitialized() {
 
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -130,7 +91,7 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -148,7 +109,7 @@ public boolean equals(final java.lang.Object obj) {
     com.google.cloud.eventarc.publishing.v1.PublishChannelConnectionEventsResponse other =
         (com.google.cloud.eventarc.publishing.v1.PublishChannelConnectionEventsResponse) obj;
 
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -159,7 +120,7 @@ public int hashCode() {
     }
     int hash = 41;
     hash = (19 * hash) + getDescriptor().hashCode();
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -298,17 +259,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
 
     // Construct using
     // com.google.cloud.eventarc.publishing.v1.PublishChannelConnectionEventsResponse.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -400,7 +354,7 @@ public Builder mergeFrom(
       if (other
           == com.google.cloud.eventarc.publishing.v1.PublishChannelConnectionEventsResponse
               .getDefaultInstance()) return this;
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -415,20 +369,31 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.eventarc.publishing.v1.PublishChannelConnectionEventsResponse parsedMessage =
-          null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.eventarc.publishing.v1.PublishChannelConnectionEventsResponse)
-                e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -468,7 +433,18 @@ public PublishChannelConnectionEventsResponse parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new PublishChannelConnectionEventsResponse(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishEventsRequest.java b/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishEventsRequest.java
index 2cea78fd5dec..6e993494948a 100644
--- a/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishEventsRequest.java
+++ b/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishEventsRequest.java
@@ -53,65 +53,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private PublishEventsRequest(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    int mutable_bitField0_ = 0;
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          case 10:
-            {
-              java.lang.String s = input.readStringRequireUtf8();
-
-              channel_ = s;
-              break;
-            }
-          case 18:
-            {
-              if (!((mutable_bitField0_ & 0x00000001) != 0)) {
-                events_ = new java.util.ArrayList<com.google.protobuf.Any>();
-                mutable_bitField0_ |= 0x00000001;
-              }
-              events_.add(input.readMessage(com.google.protobuf.Any.parser(), extensionRegistry));
-              break;
-            }
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      if (((mutable_bitField0_ & 0x00000001) != 0)) {
-        events_ = java.util.Collections.unmodifiableList(events_);
-      }
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.eventarc.publishing.v1.PublisherProto
         .internal_static_google_cloud_eventarc_publishing_v1_PublishEventsRequest_descriptor;
@@ -266,7 +207,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     for (int i = 0; i < events_.size(); i++) {
       output.writeMessage(2, events_.get(i));
     }
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -281,7 +222,7 @@ public int getSerializedSize() {
     for (int i = 0; i < events_.size(); i++) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(2, events_.get(i));
     }
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -299,7 +240,7 @@ public boolean equals(final java.lang.Object obj) {
 
     if (!getChannel().equals(other.getChannel())) return false;
     if (!getEventsList().equals(other.getEventsList())) return false;
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -316,7 +257,7 @@ public int hashCode() {
       hash = (37 * hash) + EVENTS_FIELD_NUMBER;
       hash = (53 * hash) + getEventsList().hashCode();
     }
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -446,19 +387,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.eventarc.publishing.v1.PublishEventsRequest.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {
-        getEventsFieldBuilder();
-      }
     }
 
     @java.lang.Override
@@ -468,10 +400,11 @@ public Builder clear() {
 
       if (eventsBuilder_ == null) {
         events_ = java.util.Collections.emptyList();
-        bitField0_ = (bitField0_ & ~0x00000001);
       } else {
+        events_ = null;
         eventsBuilder_.clear();
       }
+      bitField0_ = (bitField0_ & ~0x00000001);
       return this;
     }
 
@@ -593,7 +526,7 @@ public Builder mergeFrom(com.google.cloud.eventarc.publishing.v1.PublishEventsRe
           }
         }
       }
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -608,18 +541,49 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.eventarc.publishing.v1.PublishEventsRequest parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                channel_ = input.readStringRequireUtf8();
+
+                break;
+              } // case 10
+            case 18:
+              {
+                com.google.protobuf.Any m =
+                    input.readMessage(com.google.protobuf.Any.parser(), extensionRegistry);
+                if (eventsBuilder_ == null) {
+                  ensureEventsIsMutable();
+                  events_.add(m);
+                } else {
+                  eventsBuilder_.addMessage(m);
+                }
+                break;
+              } // case 18
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.eventarc.publishing.v1.PublishEventsRequest) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -1111,7 +1075,18 @@ public PublishEventsRequest parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new PublishEventsRequest(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };
 
diff --git a/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishEventsResponse.java b/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishEventsResponse.java
index d2a35002f2c8..fa595a792084 100644
--- a/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishEventsResponse.java
+++ b/java-eventarc-publishing/proto-google-cloud-eventarc-publishing-v1/src/main/java/com/google/cloud/eventarc/publishing/v1/PublishEventsResponse.java
@@ -50,45 +50,6 @@ public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
     return this.unknownFields;
   }
 
-  private PublishEventsResponse(
-      com.google.protobuf.CodedInputStream input,
-      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-      throws com.google.protobuf.InvalidProtocolBufferException {
-    this();
-    if (extensionRegistry == null) {
-      throw new java.lang.NullPointerException();
-    }
-    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
-        com.google.protobuf.UnknownFieldSet.newBuilder();
-    try {
-      boolean done = false;
-      while (!done) {
-        int tag = input.readTag();
-        switch (tag) {
-          case 0:
-            done = true;
-            break;
-          default:
-            {
-              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
-                done = true;
-              }
-              break;
-            }
-        }
-      }
-    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-      throw e.setUnfinishedMessage(this);
-    } catch (com.google.protobuf.UninitializedMessageException e) {
-      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
-    } catch (java.io.IOException e) {
-      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
-    } finally {
-      this.unknownFields = unknownFields.build();
-      makeExtensionsImmutable();
-    }
-  }
-
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.cloud.eventarc.publishing.v1.PublisherProto
         .internal_static_google_cloud_eventarc_publishing_v1_PublishEventsResponse_descriptor;
@@ -118,7 +79,7 @@ public final boolean isInitialized() {
 
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
-    unknownFields.writeTo(output);
+    getUnknownFields().writeTo(output);
   }
 
   @java.lang.Override
@@ -127,7 +88,7 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    size += unknownFields.getSerializedSize();
+    size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -143,7 +104,7 @@ public boolean equals(final java.lang.Object obj) {
     com.google.cloud.eventarc.publishing.v1.PublishEventsResponse other =
         (com.google.cloud.eventarc.publishing.v1.PublishEventsResponse) obj;
 
-    if (!unknownFields.equals(other.unknownFields)) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
 
@@ -154,7 +115,7 @@ public int hashCode() {
     }
     int hash = 41;
     hash = (19 * hash) + getDescriptor().hashCode();
-    hash = (29 * hash) + unknownFields.hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -284,17 +245,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.cloud.eventarc.publishing.v1.PublishEventsResponse.newBuilder()
-    private Builder() {
-      maybeForceBuilderInitialization();
-    }
+    private Builder() {}
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
-      maybeForceBuilderInitialization();
-    }
-
-    private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
@@ -379,7 +333,7 @@ public Builder mergeFrom(com.google.cloud.eventarc.publishing.v1.PublishEventsRe
       if (other
           == com.google.cloud.eventarc.publishing.v1.PublishEventsResponse.getDefaultInstance())
         return this;
-      this.mergeUnknownFields(other.unknownFields);
+      this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
     }
@@ -394,19 +348,31 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      com.google.cloud.eventarc.publishing.v1.PublishEventsResponse parsedMessage = null;
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
       try {
-        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-        parsedMessage =
-            (com.google.cloud.eventarc.publishing.v1.PublishEventsResponse)
-                e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
-        }
-      }
+        onChanged();
+      } // finally
       return this;
     }
 
@@ -443,7 +409,18 @@ public PublishEventsResponse parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          return new PublishEventsResponse(input, extensionRegistry);
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
         }
       };