public FieldConfig(String fieldName) {if (fieldName == null) {throw new IllegalArgumentException("field name must not be null!");}this.fieldName = fieldName;}

public FieldConfig ( String fieldName ) { if ( fieldName == null ) { throw new IllegalArgumentException ( "field name must not be null!" ) ; } this . fieldName = fieldName ; }
public FieldConfig(string fieldName){if (fieldName == null){throw new ArgumentException("field name should not be null!");}this.fieldName = fieldName;}
