Decompress GZip string in Java

I can find plenty of functions that let you decompress a GZip file, but how do I decompress a GZip string?

I'm trying to parse a HTTP response where the response body is compressed with GZip. However, the entire response is simply stored in a string so part of the string contains binary chars.

I'm attempting to use:

byte responseBodyBytes[] = responseBody.getBytes();
ByteArrayInputStream bais = new ByteArrayInputStream(responseBodyBytes); 
GZIPInputStream gzis = new GZIPInputStream(bais);

But that just throws an exception: java.io.IOException: Not in GZIP format