Here you can find the source of readBytes(InputStream inputStream)
public static byte[] readBytes(InputStream inputStream) throws IOException
//package com.java2s; //License from project: Open Source License import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; public class Main { public static byte[] readBytes(InputStream inputStream) throws IOException { ByteArrayOutputStream byteBuffer = new ByteArrayOutputStream(); int bufferSize = 1024; byte[] buffer = new byte[bufferSize]; int len = 0; while ((len = inputStream.read(buffer)) != -1) { byteBuffer.write(buffer, 0, len); }//from w w w. ja v a2 s . c om return byteBuffer.toByteArray(); } }