How do I "add" an integer onto the end of a Java byte array?

Question

Say I have a string

String myString = "the quick brown fox jumps over the lazy dog";

and I convert it to a byte array

byte[] myByteArray = myString.getBytes();

then, say I have an int

int myInt = 42;

and I convert it to a byte

byte myByte = (byte) myInt;

now, say I would like to add the int to the byte array so that when I print the array, it prints out

the quick brown fox jumps over the lazy dog42

I tried this, but it didn't work

byte[] newByteArray = new byte[myByteArray.length + 1];
System.arraycopy(myByteArray, 0, newByteArray, 0, myByteArray.length);
newByteArray[newByteArray.length-1] = myByte;
String finalString = new String(newByteArray);
System.out.println(finalString);

All that gets printed out is

the quick brown fox jumps over the lazy dog*

'*' being the ASCII character 42.

So, what is the simplest way to do this?

EDIT:

Yes, I know I can append the String "42" to my other string, but I want the integer value stored in the byte array. I was under the assumption that a byte was a byte, and it did not matter if it was a String or an int, because bytes were 1s and 0s under the hood.

Answer 1

How about:

String myString = "the quick brown fox jumps over the lazy dog";
int myInt = 42;
String temp = myString + String.valueOf(myInt);
byte[] myByteArray = temp.getBytes();

Answer 2

The simplest way would be to just append the int to the end of the string:

myString = myString + myInt;

Otherwise, you'll need to append the bytes for the characters '4' and '2' to an expanded byte array, as Sotirios Delimanolis suggested.

I would like to add that using myString.getBytes() is a very bad idea. The getBytes() method uses the default platform encoding which can differ from system to system, JVM to JVM, or even run to run. You should always prefer the version that takes a Charset as a parameter so that you know what you're getting, e.g.:

myString.getBytes(StandardCharsets.UTF_8);

Or as I like to say, Always assume the default platform encoding is EBCDIC and act accordingly.

Answer 3

Updated answer, so as to bypass charset encoding, and assuming it is required to get the characters:

            String numString = String.valueOf (newInt);
            String newString  = myString + newInt;
            int newLength = myString.length() + numString.length();
            char[] newCharArray = new char[newLength];

            newString.getChars(0, newLength, newCharArray, 0);

With David's comment:

     String newString  = myString + newInt;
     char[] newCharArray = newString.toCharArray();