- File compatibility.mkd — part of check-in [6ab585cc0e] at 2018-12-22 17:55:35 on branch trunk — Compatibility document updates. (user: stephanie.gawroriski size: 2155)
SquirrelJME aims to be compatible with most programs however there are situations and rare edge cases where there will be no compatibility. This is to make the implementation easier.
Flushable does not exist in Java ME and as such it does not
exist in SquirrelJME.
LCDUI Display Input
Only the first display (index zero) supports input events such as keyboard, buttons, mice, and touchscreen. Any secondary displays which are attached will not have events handled for them at all. This is to make it easier to implement.
lock is initialized to
null instead of
Since SquirrelJME uses a reference counted garbage collector the
lock object in the default constructor is set to
null instead of
This is so that readers do not remain in memory unable to be freed because
objects still refer to them and such.
SUPER is always assumed to be set.
In all clases the
SUPER flag is assumed to be set, this flag just modifies
the behavior of
invokespecial. When it is not set then that instruction
can invoke nearly every method directly (it was called before
invokenonvirtual). However, the Java compiler since Java 1.1 always set
the flag for classes it compiled. Since CLDC 1.0 was released well after
Java 2 was and is defined as a Java 2 virtual machine all code written for
J2ME should have classes where this flag is set. As such instead of
supporting the logic to handle cases where it is not set, the flag will just
be ignored and assumed to be set.
Only the following character encodings are supported:
Note that UTF codepoints above U+FFFF are not fully supported and are not available in Java ME. Surrogate pairs in UTF-16 will be encoded in UTF-8 as six bytes. Additionally when decoding, if a sequence that is above U+FFFF is read then it will decode to the replacement character. This may cause a loss of or mutation of data when processing files.