public Builder setExternalId(java.lang.String value) {
      if (value == null) {
        throw new NullPointerException();
      }
      externalId_ = value;
      bitField0_ |= 0x00000004;
      onChanged();
      return this;
    }
<pre>
Required. Client side company identifier, used to uniquely identify the
company.

The maximum number of allowed characters is 255.
</pre>

<code>string external_id = 3 [(.google.api.field_behavior) = REQUIRED];</code>

@param value The externalId to set.
@return This builder for chaining.
java-talent/proto-google-cloud-talent-v4beta1/src/main/java/com/google/cloud/talent/v4beta1/Company.java