ADDITIONAL SYSTEM INFORMATION :
Windows 11 Pro 24H2
The version reported by “javac --version” and “java --version” is 23.0.2.


A DESCRIPTION OF THE PROBLEM :
Other prominent regular expression engines do not accept patterns that contain multiple quantifiers of type “a{2}{3}”. However, the java.util.regex package appears to accept this pattern, interpreting it as “a{2}”. The “{3}” is silently disregarded.

One library (in C++) interprets “a{2}{3}” as “(a{2}){3}”, or “a{6}”, which seems logical, though this is atypical. Another library (in Rust) interprets “a{2}{3}” as “aa” followed by “{”, “3” and “}”.

Most major engines produce errors in this situation. Java should likely do the same.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the sample code that searches for “a{2}{3}” in “aa”.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
According to general practice, the pattern should be rejected. The Pattern.compile should throw an exception.
ACTUAL -
The “a{2}{3}” pattern is accepted as “a{2}”, and the program prints the found segment: “0..2”.

---------- BEGIN SOURCE ----------
import java.util.regex.*;

class MultipleQuantifiersDefect
{
    public static void main( String[] args)
    {
        Pattern pattern = Pattern.compile( "a{2}{3}");
        Matcher matcher = pattern.matcher( "aa");

        while( matcher.find( ))
        {
            System.out.printf( "%d..%d %n", matcher.start( ), matcher.end( ));
        }
    }
}

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