JSONArray jSONArray = jSONObject.getJSONArray(JSONConstant.BYTE_ARRAY_LIST);
    int len = jSONArray.length();
    for (int i = 0; i < len; i++) {
        byte[] b = jSONArray.get(i).toString().getBytes();
       //Following line creates pdf file of this byte arry "b"
        FileCreator.createPDF(b, "test PDF From Web Resource.pdf");

    }
}

FileCreator.createPDF(b, "test PDF From Web Resource.pdf");

JSONObject jSONObject = new JSONObject();
jSONObject.put(JSONConstant.BYTE_ARRAY_LIST, bList);

public static void main(String... args) throws JSONException{
    JSONObject o = new JSONObject();
    byte[] b = "hello".getBytes();
    o.put("A", b);
    System.out.println(o.get("A"));
}

[B@1bd8c6e

<dependency>
  <groupId>commons-codec</groupId>
  <artifactId>commons-codec</artifactId>
  <version>1.6</version>
  <type>jar</type>
</dependency>

byte[] bArray=jSONObject.getString(key).toString().getBytes();

byte[] bArray=(myByteArray);
//Following is the code that encoded my byte array and kept on String
String encodedString = org.apache.commons.codec.binary.Base64.encodeBase64String(bArray);
jSONObject.put(JSONConstant.BYTE_ARRAY_LIST , encodedString);

String getBackEncodedString = jSONObject.getString(JSONConstant.BYTE_ARRAY_LIST);
//Following code decodes to encodedString and returns original byte array
byte[] backByte = org.apache.commons.codec.binary.Base64.decodeBase64(getBackEncodedString);
//Creating pdf file of this backByte
FileCreator.createPDF(backByte, "fileAfterJSONObject.pdf");