@java.lang.Override
  public java.lang.String getFormatConversionsOrThrow(java.lang.String key) {
    if (key == null) {
      throw new NullPointerException("map key");
    }
    java.util.Map<java.lang.String, java.lang.String> map = internalGetFormatConversions().getMap();
    if (!map.containsKey(key)) {
      throw new java.lang.IllegalArgumentException();
    }
    return map.get(key);
  }
<pre>
Optional. The file format conversion map that is applied to all input
files. The map key is the original mime_type. The map value is the target
mime_type of translated documents.

Supported file format conversion includes:
- `application/pdf` to
  `application/vnd.openxmlformats-officedocument.wordprocessingml.document`

If nothing specified, output files will be in the same format as the
original file.
</pre>

<code>
map&lt;string, string&gt; format_conversions = 8 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-translate/proto-google-cloud-translate-v3/src/main/java/com/google/cloud/translate/v3/BatchTranslateDocumentRequest.java