Java tutorial
import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.InputStream; public class Main { public static void main(String[] arg) throws Throwable { File f = new File(arg[0]); InputStream in = new FileInputStream(f); byte[] buff = new byte[8000]; int bytesRead = 0; ByteArrayOutputStream bao = new ByteArrayOutputStream(); while ((bytesRead = in.read(buff)) != -1) { bao.write(buff, 0, bytesRead); } in.close(); byte[] data = bao.toByteArray(); ByteArrayInputStream bin = new ByteArrayInputStream(data); System.out.println(bin.available()); } }