@java.lang.Override
  public java.lang.String getCustomClassId() {
    java.lang.Object ref = customClassId_;
    if (ref instanceof java.lang.String) {
      return (java.lang.String) ref;
    } else {
      com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
      java.lang.String s = bs.toStringUtf8();
      customClassId_ = s;
      return s;
    }
  }
<pre>
Required. The ID to use for the custom class, which will become the final
component of the custom class' resource name.

This value should restrict to letters, numbers, and hyphens, with the first
character a letter, the last a letter or a number, and be 4-63 characters.
</pre>

<code>string custom_class_id = 2 [(.google.api.field_behavior) = REQUIRED];</code>

@return The customClassId.
java-speech/proto-google-cloud-speech-v1/src/main/java/com/google/cloud/speech/v1/CreateCustomClassRequest.java