Although the previous text spoke about loading class files, the IDE does not use true class files much. When a file is compiled by the IDE, the result is not a class file, but rather a "signature" file. These files contain specification of classes and signatures of their members. The main differences between class files and signature files are:
The format of the signature files is subject of change at any time, as it is used only to create the IDE's caches.
Note: for most purposes, it is not important if an Element has been load from the class file or from the signature file.