FULL PRODUCT VERSION :
java version "1.6.0_02"
Java(TM) SE Runtime Environment (build 1.6.0_02-b06)
Java HotSpot(TM) Client VM (build 1.6.0_02-b06, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
The following examples is OK.
System.out.println("\uD834\uDD22".matches("[\\uD834\\uDD21-\uD834\uDD24]+"));

but, the following examples, PatternSyntaxException is generated.
System.out.println("\uD834\uDD21".matches("[\\uD834\\uDD21-\\uD834\\uDD22]+"));


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile and run the following.


import java.util.regex.Pattern;
public class Sample {
    // U+1D121 is \uD834\uDD21
    public static void main(String[] args) {
        System.out.println("\uD834\uDD22".matches("[\\uD834\\uDD21-\uD834\uDD24]+"));
        System.out.println("\uD834\uDD21".matches("[\\uD834\\uDD21-\uD834\uDD22]+"));
    }
}


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
true
true
ACTUAL -
true
Exception in thread "main" java.util.regex.PatternSyntaxException: Illegal character range near index 19
[\uD834\uDD21-\uD834\uDD22]+
                   ^
        at java.util.regex.Pattern.error(Unknown Source)
        at java.util.regex.Pattern.range(Unknown Source)
        at java.util.regex.Pattern.clazz(Unknown Source)
        at java.util.regex.Pattern.sequence(Unknown Source)
        at java.util.regex.Pattern.expr(Unknown Source)
        at java.util.regex.Pattern.compile(Unknown Source)
        at java.util.regex.Pattern.<init>(Unknown Source)
        at java.util.regex.Pattern.compile(Unknown Source)
        at java.util.regex.Pattern.matches(Unknown Source)
        at java.lang.String.matches(Unknown Source)
        at Sample.main(Sample.java:10)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.util.regex.Pattern;
public class Sample {
    // U+1D121 is \uD834\uDD21
    public static void main(String[] args) {
        System.out.println("\uD834\uDD22".matches("[\\uD834\\uDD21-\uD834\uDD24]+"));
        System.out.println("\uD834\uDD21".matches("[\\uD834\\uDD21-\uD834\uDD22]+"));
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
The upper example shows.