What software do I need to modified/moding an application?

What software do I need to modified/moding an application such as Opera Mini v4 and v5? I gave my best answer The one who can help with my topic. This is my project moding an application. And I choose to modified opera mini. Iwant to change the splash screen. And I dont how?What software do I need to modified/moding an application?You need the program's source code, a text editor and a compiler for the language the program was written in. (And, for some languages, an IDE for the language.)What software do I need to modified/moding an application?depends what the program was written in