public Aggregate withGroups(java.util.Collection<java.util.List<String>> groups) {
        setGroups(groups);
        return this;
    }
<p>
Specifies the fields to group by.
</p>

@param groups
       Specifies the fields to group by.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-glue/src/main/java/com/amazonaws/services/glue/model/Aggregate.java