How to convert a String of this type to a Date Object

If the string is even in the form it presented, also containing the XML data type, ie ["2015-06-30T16:38:53"^^xsd:dateTime] , one way to do it would be to retrieve only the relevant part with an expression regular, and then use a DateFormat .

An example regular expression would look like this:

\d+\-\d+\-\d+T\d+\:\d+\:\d+

A complete example would look like this:

final String dateFormat = "yyyy-MM-dd'T'HH:mm:ss";
final String dateOnOWL = "[\"2015-06-30T16:38:53\"^^xsd:dateTime]";
final Pattern pattern = Pattern.compile("\d+\-\d+\-\d+T\d+\:\d+\:\d+");
final Matcher matcher = pattern.matcher(dateOnOWL);

if (matcher.find()) {
    final String result = matcher.group();
    final DateFormat sdf = new SimpleDateFormat(dateFormat);
    final Date date = sdf.parse(result);
    System.out.println(date);
} else {
    System.out.println(String.format("Padrão não encontrado em %s", dateOnOWL));
}

Regular expression is just an example of how to apply, you can improve it if you use this approach.

The simple way is to tell from which position the formatter ( DateFormat ) should start using the pattern we are using. To do this you should use a ParsePosition informing that we will start of the 2 index position, that is 2 of 2015 . As the default will only be up to seconds, the formatter will ignore the rest.

An example would be something like this, which generates the same result:

final String dateFormat = "yyyy-MM-dd'T'HH:mm:ss";
final String dateOnOWL = "[\"2015-06-30T16:38:53\"^^xsd:dateTime]";
final DateFormat sdf = new SimpleDateFormat(dateFormat);
final ParsePosition position = new ParsePosition(2);
final Date date = sdf.parse(dateOnOWL, position);
System.out.println(date);