Convert Reader to InputStream (and Back) in Java
Convert a Reader to InputStream in Java with a String, OutputStreamWriter or Commons IO ReaderInputStream, and back with InputStreamReader and a charset.
OutputStream to InputStream in Java: Byte Array or Piped Streams
Convert OutputStream to InputStream in Java with ByteArrayOutputStream, piped streams in a second thread or a temp file, and avoid pipe deadlocks.
InputStream to String in Java: readAllBytes and More (Java 25)
Convert an InputStream to String in Java with readAllBytes, readAllAsString or BufferedReader, plus String to InputStream and StringReader examples.