Before you go through 'how to resize boot camp' process, you first need to understand the the term ' Boot camp' and the need to resize it.
Boot camp is a multi boot utility tool included in Apple Inc.'s OS X assisting the users in installing the Windows operating system on Intel based Macintosh computers. This utility tool guides its users how to partition their hard disk drive and install Windows OS through non-destructive way. Or you can say, Boot Camp utility help you partition your hard drive into two partitions. One partition is used by Mac itself to run its OS and other is used to run Windows OS.
This disk partitioning is necessary so as to run two completely different operating system. Because, both Mac and Windows do not run on the same format. Windows OS run on NTFS whereas Mac runs on Mac OS X i.e, Journaled. And so partitioning disk drives enable both OS to run separately with their own format on the same drive. This NTFS partition is also called Boot camp partitions used to install Windows.
Now you can run your windows with new Boot Camp partitions. Under some conditions, you may need to either increase or decrease storage space in Boot camp partition. Or you may find that Boot camp partition is running out of space so you want to add more space to Boot camp. This is a kind of serious requirement when you run out of storage space in Boot camp.
Since windows uses NTFS file system, Mac's Disk Utility is not able to resize Boot camp partitions. Process like resizing requires taking backup of Boot camp partition, deletion of same and again creating required sized partition using Boot camp assistant tool. This resizing process may seem difficult for you. Therefore, Stellar Partition Manger resizes the Boot camp partition and allow you to easily adjust the size of Windows as well as Mac partitions.