public com.google.cloud.vertexai.api.ExplanationMetadata.OutputMetadata.Builder
        putOutputsBuilderIfAbsent(java.lang.String key) {
      java.util.Map<
              java.lang.String,
              com.google.cloud.vertexai.api.ExplanationMetadata.OutputMetadataOrBuilder>
          builderMap = internalGetMutableOutputs().ensureBuilderMap();
      com.google.cloud.vertexai.api.ExplanationMetadata.OutputMetadataOrBuilder entry =
          builderMap.get(key);
      if (entry == null) {
        entry = com.google.cloud.vertexai.api.ExplanationMetadata.OutputMetadata.newBuilder();
        builderMap.put(key, entry);
      }
      if (entry instanceof com.google.cloud.vertexai.api.ExplanationMetadata.OutputMetadata) {
        entry =
            ((com.google.cloud.vertexai.api.ExplanationMetadata.OutputMetadata) entry).toBuilder();
        builderMap.put(key, entry);
      }
      return (com.google.cloud.vertexai.api.ExplanationMetadata.OutputMetadata.Builder) entry;
    }
<pre>
Required. Map from output names to output metadata.

For Vertex AI-provided Tensorflow images, keys can be any user defined
string that consists of any UTF-8 characters.

For custom images, keys are the name of the output field in the prediction
to be explained.

Currently only one key is allowed.
</pre>

<code>
map&lt;string, .google.cloud.vertexai.v1.ExplanationMetadata.OutputMetadata&gt; outputs = 2 [(.google.api.field_behavior) = REQUIRED];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/ExplanationMetadata.java