Byte [] != Byte []

What is this all about...

This code:

    String str = new String( "HI!" );
    byte [] b1 = str.getBytes( "UTF8" );
    byte [] b2 = str.getBytes( "UTF8" );
    System.out.println( b1.equals(b2) );

Outputs:

    False

But why? Can I compare two arrays without having to compare each individual element?
LVL 25
InteractiveMindAsked:
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KuldeepchaturvediCommented:
nopes
b1 & b2 are two separate objects.. i.e. if you try to == it will come out as false...

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InteractiveMindAuthor Commented:
Okay, fair enough. But, would you agree that the *content* of the two byte arrays in my above example would be equivalent? (I think we all know that they are), in which case, why do I get errors when I do the following:

    String sPT = new String( "Experts Exchange" );
    byte [] bPT = sPT.getBytes( "UTF8" );
   
    byte [] bCT = encrypt( bPT );
    String sCT = new String( bCT, "UTF8" );
   
    bCT = sCT.getBytes( "UTF8" );            // With this line
   
    bPT = decrypt( bCT );
    sPT = new String( bPT, "UTF8" );

Than when I do this:

    String sPT = new String( "Experts Exchange" );
    byte [] bPT = sPT.getBytes( "UTF8" );
   
    byte [] bCT = encrypt( bPT );
    String sCT = new String( bCT, "UTF8" );
   
    bPT = decrypt( bCT );
    sPT = new String( bPT, "UTF8" );

??

Does that make sense to you?
InteractiveMindAuthor Commented:
i.e.

    byte [] bCT = encrypt( bPT );
    String sCT = new String( bCT, "UTF8" );
   
    bCT = sCT.getBytes( "UTF8" );

causes problems, but it's fine when I don't use that last line... surely it should produce the same result as the first line?!
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KuldeepchaturvediCommented:
and your encypted byte array and the byte that you get out of the encrypted strings are not  matching......right?
InteractiveMindAuthor Commented:
Ah ha... nevermind about that one; I've figured it .... there was a bug in my decrypt() method; I wasn't using UTF8 how I should have been.

:-)

Thanks all the same.
KuldeepchaturvediCommented:
then I dont really deserve those points...:-)
What was the problem by the way if you dont mind sharing
InteractiveMindAuthor Commented:
Well, you answered my original question; so, I think the points should be yours..


I'd setup 2 methods, one to encrypt a byte array, the other to decrypt..

When I retrieved the ciphertext version of the data to be encrypted, like so:
   
   byte [] b = encrypt(); // Obviously, I'd pass the required parameters to this method
   
I then binded the byte array to a string like so:

   String s = new String( b, "UTF8" );
   
Then, if I wanted to decrypt 's', rather than using 'b', I done the following:

   byte [] b2 = s.getBytes( "UTF8" );
   
Expecting b2 to be the same as b.. They weren't however, which was resulting in an exception when I attempted to re-encrypt..

What was causing 'b' != 'b2', was that in the decrypt method, I wasn't converting the data into UTF8 when I needed to....... But that's now fixed. :-)
dberner9Commented:
Use Arrays.equals(b1,b2) to compare arrays by content.
InteractiveMindAuthor Commented:
Oh yeah! Thanks for that dberner9 :-)
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