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> Internally, the model of a String is UTF-16-like, a sequence of unsigned 16-bit `char` values. That is not 100% true anymore. Java 9 (September 2017) changed

> Internally, the model of a String is UTF-16-like, a sequence of unsigned 16-bit `char` values. That is not 100% true anymore. Java 9 (September 2017) changed “the internal representation of the String class from a UTF-16 char array to a byte array plus an encoding-flag field. The new String class will store characters encoded either as ISO-8859-1/Latin-1 (one byte per character), or as UTF-16 (two bytes per character), based upon the contents of the string. The encoding flag will indicate which encoding is used.” (https://openjdk.org/jeps/254 https://openjdk.org/jeps/254)

smarks 4y ago
The model of a String, internal to the JVM, as manifested in the `java.lang.String` API, is still UTF-16-like. The internal representation has changed to be either UTF-16-like or Latin-1. JEP 254 didn't change the API. This is invisible to Java programs, and they can't tell which internal representation is being used. If a Java program wants a byte array from a String, it still has to go through the APIs that involve codeset conversion. There are suitable fast paths, though. For example, if the program requests Latin-1 and the internal representation is Latin-1, the result is just a straight copy of the internal array.