What's a good compression library for Java?

Question

I need to compress portions of our application's network traffic for performance. I presume this means I need to stay away from some of the newer algorithms like bzip2, which I think I have heard is slower.

Answer 1

You can use Deflater/Inflater which is built into the JDK. There are also GZIPInputStream and GZIPOutputStream, but it really depends on your exact use.

Edit:

Reading further comments it looks like the network taffic is HTTP. Depending on the server, it probably has support for compression (especially with deflate/gzip). The problem then becomes on the client. If the client is a browser it probably already supports it. If your client is a webservices client or an http client check the documentation for that package to see if it is supported.

It looks like jakarta-commons httpclient may require you to manually do the compression. To enable this on the client side you will need to do something like

.addRequestHeader("Accept-Encoding","gzip,deflate");

Answer 2

If the network traffic is going over HTTP, most of the various web servers/servlet containers support for negotiated zipping, e.g., mod_deflate for Apache.

Answer 3

Your compression algorithm depends on what your trying to optimize, and how much bandwidth you have available.

If you're on a gigibit LAN, almost any compression algorithm is going to slow your program down just a bit. If your connecting over a WAN or internet, you can afford to do a bit more compression. If you connected to a dialup, you should compress as much as it absolutely possible.

If this is a WAN, you may find hardware solutions like Riverbed's are more effective, as they work across a range of traffic, and don't require any changes to software.

I have a test case which shows the relative compression difference between Deflate, Filtered, BZip2, and lzma. Simply plug in a sample of your data, and test the timing between two machines.