What is the use of the FileDescriptor class in Java and its in, out, and err methods?

Question

What is the use of the FileDescriptor class in Java? We can only get it using getFD () methods in streams, and then we can use the resulting FD to create another instance, say, FileInputStream, which we can also do by creating a FileInputStream object with the same file name (instead of using its FD) .

In addition, the in, out, and err methods. what use can they be applied to?

Answer 1

As JavaDoc says:

, , , . - FileInputStream FileOutputStream, .

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, JDK