What do you normally do with a File? A file is used to store your documents. Right? In Java, a file is treated as a stream of characters, objects or any primitive data types and saved in a computer file such as myexpenses.txt. Java has a basic package java.io that contains all File related classes to handle file reading, writing and manipulating the contents.
A Stream can be defined as a continuous sequence of data. In Java, InputStream is used to read data from a source and OutputStream is used to write data to a destination. The InputStream can be the computer Console input, or a file, or a webpage content from an URL etc. Similarly, an OutputStream can be the computer monitor, a computer file, a server socket etc.
Here is a list of Java File Tutorials that will show you how to handle files in Java Programs