Dear Yasheel,
Thanks for considering Aspose.Slides for JAVA.
1- Yes, you can combine number of slides from different presentations into a single one.
Presentation class has 2 cloneSlide methods. And it can clone slides from other presentations.
Please check cloneslide demo code. It shows how to copy all slides from one presentation to another.
You can get cloneslide demo code from directory aspose.slides\examples\cloneslide when you unzip Aspose.Slides Java.
2- The demo will also show you how to save your presentation onto disk
Note: If you want to use Aspose.Slides for .NET all the above things hold, you will get the example code from Aspose.Slides\Demos\C#|VB\CloneSlides directory
Many Thanks and Kind Regards,
Shakeel Faiz
Support Engineer
Aspose Tyumen Team