public Builder putAnnotations(java.lang.String key, java.lang.String value) {
      if (key == null) {
        throw new NullPointerException("map key");
      }
      if (value == null) {
        throw new NullPointerException("map value");
      }
      internalGetMutableAnnotations().getMutableMap().put(key, value);
      bitField0_ |= 0x00000010;
      return this;
    }
<pre>
Optional. Client-specified annotations.
</pre>

<code>map&lt;string, string&gt; annotations = 5 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-workstations/proto-google-cloud-workstations-v1beta/src/main/java/com/google/cloud/workstations/v1beta/WorkstationCluster.java