Core Java: An anonymous class captures effectively final locals but cannot reassign them

An anonymous inner class can read a local variable from its enclosing scope as long as that variable is never reassigned after the class is created, the same effectively-final rule lambdas follow.

Code

int base = 10;
Runnable r = new Runnable() {
    @Override public void run() {
        System.out.println("Captured base: " + base);
    }
};
r.run();
System.out.println("base is still: " + base);

Output

Captured base: 10
base is still: 10