$ java -Xmx3g  MillionStrings      (JDK 27)
java.version = 27
strings                      : 1,000,000 (average 42.50 chars)
coder == 0 (LATIN1) in set A : 1,000,000
coder == 1 (UTF16)  in set B : 1,000,000
# WARNING: Unable to attach Serviceability Agent. sun.jvm.hotspot.runtime.VM.isCompressedKlassPointersEnabled()
A: lower-case ASCII only     : 86,150,520 bytes  (86.2 MB, 86.2 bytes per string)
B: same + one euro sign      : 130,145,168 bytes  (130.1 MB, 130.1 bytes per string)
B / A                        : 1.511