@java.lang.Override
  public java.lang.String getSourceSentence() {
    java.lang.Object ref = sourceSentence_;
    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();
      sourceSentence_ = s;
      return s;
    }
  }
<pre>
Required. The source sentence.
</pre>

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

@return The sourceSentence.
java-translate/proto-google-cloud-translate-v3/src/main/java/com/google/cloud/translate/v3/AdaptiveMtSentence.java