Why doesn't java.io.File have a close method?

The javadoc of the File class describes the class as:

An abstract representation of file and directory pathnames.

File is only a representation of a pathname, with a few methods concerning the filesystem (like exists()) and directory handling but actual streaming input and output is done elsewhere. Streams can be opened and closed, files cannot.

(My personal opinion is that it's rather unfortunate that Sun then went on to create RandomAccessFile, causing much confusion with its inconsistent naming.)

java.io.File doesn't represent an open file, it represents a path in the filesystem. Therefore having close method on it doesn't make sense.

Actually, this class was misnamed by the library authors, it should be called something like Path.

Essentially random access file wraps input and output streams in order to manage the random access. You don't open and close a file, you open and close streams to a file.