Why can't an identifier begin with a digit in java

Question

I can not think anything other than "string of digits would be a valid identifier as well as a valid number."

Is there any other explanation other than this one?

Answer 1

Because that would make telling number literals from symbols names a serious PITA.

For example with a digit being valid for the first character a variables of the names 0xdeadbeef or 0xc00lcafe were valid. But that could be interpreted as a hexadecimal number as well. By limiting the first character of a symbol to be a non-digit, ambiguities of that kind are avoided.

Answer 2

If it could then this assignment would be possible

int 33 = 44; // oh oh 

then how would the JVM distinguish between a numeric literal and a variable?