Restricted keywords

There are ten words that are called restricted keywords: open, module, requires, transitive, exports, opens, to, uses, provides, and with. They are called restricted because they cannot be identifiers in the context of a module declaration, which we will not discuss in this book. In all other places, it is possible to use them as identifiers. Here is one example of such usage:

int to = 1;
int open = 1;
int uses = 1;
int with = 1;
int opens =1;
int module = 1;
int exports =1;
int provides = 1;
int requires = 1;
int transitive = 1;

However, it is a good practice not to use them as identifiers anywhere. There are plenty of other ways to name a variable.