[What is InputStream & Output Stream in Java? Why and when do we use them?] #java

streams.md

The goal of InputStream and OutputStream is to abstract different ways to input and output: whether the stream is a file, a web page, or the screen shouldn't matter. All that matters is that you receive information from the stream (or send information into that stream.)

InputStream is used for many things that you read from.

OutputStream is used for many things that you write to.

Here's some sample code. It assumes the InputStream instr and OutputStream osstr have already been created:

int i;
while ((i = instr.read()) != -1) {
    osstr.write(i);
}

instr.close();
osstr.close();

Ref:

• Stackoverflow answers