How do I use the IsAlphabetic binary property in a

I'm using this pattern to check if a string starts with at least 2 alphabetic characters in front a colon:

string.matches("^\\p{IsAlphabetic}{2,}:")

but I get the following exception thrown at me:

java.util.regex.PatternSyntaxException: Unknown character property name {Alphabetic} near index 16
    ^\p{IsAlphabetic}{2,}:
    ^
    at java.util.regex.Pattern.error(Pattern.java:1730)
    at java.util.regex.Pattern.charPropertyNodeFor(Pattern.java:2454)
    at java.util.regex.Pattern.family(Pattern.java:2429)
    at java.util.regex.Pattern.sequence(Pattern.java:1848)
    at java.util.regex.Pattern.expr(Pattern.java:1769)
    at java.util.regex.Pattern.compile(Pattern.java:1477)
    at java.util.regex.Pattern.<init>(Pattern.java:1150)
    at java.util.regex.Pattern.compile(Pattern.java:840)
    at java.util.regex.Pattern.matches(Pattern.java:945)
    at java.lang.String.matches(String.java:2102)

even though the specification of the Pattern classes states:

Binary properties are specified with the prefix Is, as in IsAlphabetic. The supported binary properties by Pattern are

Alphabetic

Ideographic

Letter

...

and the section Classes for Unicode scripts, blocks, categories and binary properties lists

\p{IsAlphabetic} An alphabetic character (binary property)

Works and returns true using java 1.8.

String s = "äö:";
System.out.println(s.matches("^\\p{IsAlphanumeric}{2,}:"));

Note that the forms available in Java 1.7 - Alpha, IsAlpha - do not necessarily include characters not in US-ASCII . This returns false:

String s = "äö:";
System.out.println(s.matches("^\\p{IsAlpha}{2,}:"));

But note that this works in 1.7 and returns true:

String s = "äö:";
Pattern pat = Pattern.compile( "^\\p{Alpha}{2,}:",
                     Pattern.UNICODE_CHARACTER_CLASS );
Matcher mat = pat.matcher( s );
System.out.println(mat.matches());