public Builder mergeDefault(com.google.protobuf.Value value) {
      if (defaultBuilder_ == null) {
        if (((bitField0_ & 0x00000020) != 0)
            && default_ != null
            && default_ != com.google.protobuf.Value.getDefaultInstance()) {
          getDefaultBuilder().mergeFrom(value);
        } else {
          default_ = value;
        }
      } else {
        defaultBuilder_.mergeFrom(value);
      }
      if (default_ != null) {
        bitField0_ |= 0x00000020;
        onChanged();
      }
      return this;
    }
<pre>
Optional. Default value of the data.
</pre>

<code>.google.protobuf.Value default = 23 [(.google.api.field_behavior) = OPTIONAL];</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/Schema.java