Is this a Java DateFormat bug?

Question

The pattern is "dd-MM-yyyy"

I think the string "01-01-2010mwwwwwwwwwwwwwww" does not satisfy the pattern, but the following code shows the contrary.

Anyone can explain why?

public static void main(String[] args) throws Exception {

    SimpleDateFormat df = new SimpleDateFormat("dd-MM-yyyy");

    Date date = df.parse("01-01-2010mwwwwwwwwwwwwwww");

    System.out.println(date);
}

Thanks

Answer 1

The parse method does not try to match the entire input string. That is, the prefix 01-01-2010 matches, and that's enough.

From DateFormat.parse:

Parses text from the beginning of the given string to produce a date. The method may not use the entire text of the given string.

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If you need to figure out if it was a "complete match", you could try the following:

SimpleDateFormat df = new SimpleDateFormat("dd-MM-yyyy");

String strDate = "01-01-2010mwwwwwwwwwwwwwww";
ParsePosition pp = new ParsePosition(0);
Date date = df.parse(strDate, pp);
System.out.println("Complete match: " + (pp.getIndex() == strDate.length()));

strDate = "01-01-2010";
pp = new ParsePosition(0);
date = df.parse(strDate, pp);
System.out.println("Complete match: " + (pp.getIndex() == strDate.length()));

This prints

Complete match: false
Complete match: true