Android Question Where to get information about a library?

Probably here.

Thanks!
I managed to send a string to a Java program running on my destop using sockects. But, I'm using this code to send see:
But before sending this string I want to send an int with the size of that string. So, how can I send an int ?
Supose my string having this value texto = "String", this string has 6 chars, so I need to send the number 6 on the firsts 4 bytes as an INT has 4 bytes,
how can I do that? Thanks!

Note that the thread title should summarize the question for it to be useful.

I recommend you to learn about AsyncStreams. This is the only correct way to manage network streams.