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From: Mike Amling <mamling@chaff.us>
Newsgroups: comp.lang.java.programmer
Subject: Re: Exception in thread "main" java.util.zip.ZipException: Not in GZIP format
Date: Thu, 23 Oct 2014 09:30:46 -0500
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On 10/23/14 3:51 AM, takouarnauld@gmail.com wrote:
> Good Morning,
>
> I'm trying in my program to Compress/Decompress data using GZIP streams and when using the charset "ISO-8859-1", everything working well but when changing the charset to "UTF-8", i'm getting the Error message "Exception in thread "main" java.util.zip.ZipException: Not in GZIP format".
> this is my code:
>
> public static String compress(String str) throws IOException {
> 	        if (str == null || str.length() == 0) {
> 	            return str;
> 	        }
> 	        System.out.println("String length : " + str.length());
> 	        ByteArrayOutputStream out = new ByteArrayOutputStream();
> 	        GZIPOutputStream gzip = new GZIPOutputStream(out);
> 	        gzip.write(str.getBytes());
> 	        gzip.close();
> 	        String outStr = out.toString("UTF-8");

You have no reason to believe that the byte array output from GZIP is 
the UTF-8 encoding of a String. <a 
href="http://docs.oracle.com/javase/8/docs/api/java/io/ByteArrayOutputStream.html#toString-java.lang.String-">Java 
doc for ByteArrayOutputStream.toString(String encoding)</a> says that 
"This method always replaces malformed-input and unmappable-character 
sequences with this charset's default replacement string". After that 
replacement, you can never recover the original contents of the byte 
array from the resultant String.

--Mike Amling
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