Bug 184853

Starting with Snow Leopard, Mac OS X supports transparent file compression on HFS+ volumes to save diskspace and reduce I/O.

$ ./afsctool -v /Applications/NetBeans/NetBeans\ 6.9\ Beta.app/
/Applications/NetBeans/NetBeans 6.9 Beta.app/:
Folder contains no compressed files
Total number of files: 2916
Total number of folders: 210
Total number of items (number of files + number of folders): 3126
Folder size (uncompressed; reported size by Mac OS 10.6+ Finder): 220342491 bytes / 227.5 MB (megabytes) / 216.9 MiB (mebibytes)
Folder size (compressed - decmpfs xattr; reported size by Mac OS 10.0-10.5 Finder): 220342491 bytes / 227.5 MB (megabytes) / 216.9 MiB (mebibytes)
Folder size (compressed): 220342491 bytes / 227.5 MB (megabytes) / 216.9 MiB (mebibytes)
Compression savings: 0.0%
Appoximate total folder size (files + file overhead + folder overhead): 228221288 bytes / 228.2 MB (megabytes) / 217.6 MiB (mebibytes)

$ ./afsctool -c /Applications/NetBeans/NetBeans\ 6.9\ Beta.app/

$ ./afsctool -v /Applications/NetBeans/NetBeans\ 6.9\ Beta.app/
/Applications/NetBeans/NetBeans 6.9 Beta.app/:
Number of HFS+ compressed files: 2332
Total number of files: 2916
Total number of folders: 210
Total number of items (number of files + number of folders): 3126
Folder size (uncompressed; reported size by Mac OS 10.6+ Finder): 220342491 bytes / 227.5 MB (megabytes) / 216.9 MiB (mebibytes)
Folder size (compressed - decmpfs xattr; reported size by Mac OS 10.0-10.5 Finder): 117885187 bytes / 120 MB (megabytes) / 114.4 MiB (mebibytes)
Folder size (compressed): 119985046 bytes / 122.1 MB (megabytes) / 116.4 MiB (mebibytes)
Compression savings: 45.5%
Appoximate total folder size (files + file overhead + folder overhead): 123545803 bytes / 123.5 MB (megabytes) / 117.8 MiB (mebibytes)

Please let the Netbeans IDE Installer use HFS compression.

References:
http://github.com/jrk/afsctool
man ditto
     --hfsCompression
                   When copying files or extracting content from an archive, if the destination
                   is an HFS+ volume that supports  compression, all the content will be compressed
                   if appropriate. This is only supported on Mac OS X 10.6 or later, and is only intended
                   to be used in installation and backup scenarios that involve system files.