Why is java case sensitive ?

Answer 1

It is not Java, but many more programming languages!

An obvious reason could be, that our spoken and written language is also case sensitive. For example „I like Reading.“ and „I like reading.“ have different meanings. The first refers to the city named Reading, the latter refers to the activity of getting information from written texts.

Furthermore, a compiler or interpreter of a case sensitive language is easier to implement, because a text normalization algorithm is not required.

Answer 2

It's the compiler that is case sensitive. This is how algorithm works

Answer 3

with case sensitive is possible make more names in same length in large project can be problem get unique short readable name. With cs. you can write
Scanner scanner;
in comfort