public static <K, V> QPair<K, V> create(Expression<K> key, Expression<V> value) {
        return new QPair<K, V>(key, value);
    }
A pair of (Map) key and value

@author sasa
@param <K> Map key type
@param <V> Map value type
querydsl-core/src/main/java/com/querydsl/core/group/QPair.java