public void setPrincipals(java.util.Collection<String> principals) {
        if (principals == null) {
            this.principals = null;
            return;
        }

        this.principals = new java.util.ArrayList<String>(principals);
    }
<p>
The principals associated with the thing.
</p>

@param principals
       The principals associated with the thing.
aws-java-sdk-iot/src/main/java/com/amazonaws/services/iot/model/ListThingPrincipalsResult.java