difference between keyword and literal in java

Question

I am new to java and was reading a book and came across these lines:

"The literals true,falseand null are lowercase,not uppercase as in C++ language.Strictly speaking,these are not keywords but literals."

why these are literals, and what requirements are needed for some keywords to be called literal..?

Answer 1

Keywords are words that are used as part of code structure, like for or while. They change the way a compiler handles a block of code, e.g. a for tells the compiler to execute the code within the specified scope repeatedly, until the given exit condition is reached. The class keyword tells the compiler to treat everything within the specified scope to be part of a particular class. Keyword names are restricted, so you can't use them as variable names.

Literals like true, false and null are values that can be assigned, but their names are restricted in the same way that keywords are, i.e. you can't have a variable called true or for. They form parts of expressions, but don't change the way a compiler handles code.