Final answer:
Java uses Input Streams and Output Streams, such as FileInputStream and FileOutputStream, to read and write data on a disk. InputStreamReader and OutputStreamWriter are used to handle character-based data, converting bytes and characters as needed.
Step-by-step explanation:
The streams that transform data from the format used on a disk to the format used in a Java program are Input Streams and Output Streams. Specifically, in Java, classes such as FileInputStream and FileOutputStream are used for reading from and writing to files, respectively.
There are also Reader and Writer classes for character-based data, such as InputStreamReader and OutputStreamWriter, which convert bytes to characters and characters to bytes, making the data usable in Java programs. These streams handle the encoding and decoding process, aligning the data representation on disk with that in the memory.