How to use

initializeChildrenFromFields

method

in

org.apache.arrow.vector.complex.UnionVector

/** Helper method which creates a union vector with no data */
private static UnionVector testEmptyUnionVector() {
 final UnionVector unionVector = new UnionVector("unionVector", ALLOCATOR, null);
 unionVector.initializeChildrenFromFields(
   asList(
     Field.nullable("intType", new ArrowType.Int(32, true)),
     Field.nullable("decimalType", new ArrowType.Decimal(4, 10))
   )
 );
 return unionVector;
}

UnionVector unionVector = new UnionVector(field.getName(), allocator, callBack);
if(!children.isEmpty()){
 unionVector.initializeChildrenFromFields(children);