Why doesn't Base64 Encoding of a byte[] in Java work?
<pre><code>import java.io.*;
import java.nio.*;
import java.util.Base64;
import java.util.UUID;
import java.io.UnsupportedEncodingException;

public class Abc {

public static String readFileAsString(String filePath) throws IOException {
    DataInputStream dis = new DataInputStream(new FileInputStream(filePath));
    try {
        long len = new java.io.File(filePath).length();
        if (len &gt; Integer.MAX_VALUE) throw new IOException("File " + filePath + " too large")
        byte[] bytes = new byte[(int) len];
        dis.readFully(bytes);
        String ans = new String(bytes, "UTF-8");
        return ans;


    } finally {
        dis.close();
    }
}

public static void main(String args[]) throws IOException {

    String base64encodedString = null;
    FileOutputStream stream = new FileOutputStream("C:\\Users\\EMP142738\\Desktop\\New folder\\Readhjbdsdsefd.pdf");


    String filePath = new String("C:\\Users\\EMP142738\\Desktop\\New folder\\Readers Quick Ref Card.pdf");
    try {

        base64encodedString = java.util.Base64.getUrlEncoder().encodeToString(new Abc().readFileAsString(filePath).getBytes("utf-8"));



    } catch (IOException e) {
        e.printStackTrace();
    }

    try {

        byte[] base64decodedBytes = java.util.Base64.getUrlDecoder().decode(base64encodedString);
        stream.write(base64decodedBytes);

    }   catch(IOException e){
    e.printStackTrace();}       
    finally {
stream.close();
}//catch (FileNotFoundException e) {
   //         e.printStackTrace();
        }
    }
</code></pre>

<p>I'm trying to encode and decode a PDF file using Base64. What I'm doing is converting a PDF(Binary File) to a ByteArray, then returning the ByteArray as a string. I'm then encoding this string in Base64, using java.util.Base64. When I try to backtrack through the process, I'm able to convert a PDF(Binary File) but the File is corrupted/damaged. Also, the output file after the entire process ( Encode- Decode) is significantly larger than the input file. I expected that both of them would be of the same size. What am I doing wrong here? </p>

<p>Edit 1( 7/13/16):
In the main method, I modified the code as per Jim's suggestion. 
I tried using Base64.encode(byte[] src) after reading the documentation of the same. However it keeps giving the error "cannot find symbol Base64.encode(byte[])". But I've used the encodetoString method from the same Class( java.util.Base64.Encoder). I'm unable to understand the issue here.
Here's the modified main method used after returning a byte[] from the readFileAsString method.</p>

<pre><code> public void main(String args[]) throws IOException {

    String filePath = new String("C:\\Users\\EMP142738\\Desktop\\New folder\\Readers Quick Ref Card.pdf");
    byte[] src = new Abc().readFileAsString(filePath);
    byte[] destination = Base64.encode(src);

   }
</code></pre>