Core Java: Instance initializer blocks run before the constructor body

Field initializers and instance initializer blocks run in textual order as the object is built, and all of them finish before the constructor's own body executes.

Code

class Widget {
    int a = log("field a");
    {
        log("instance initializer");
    }
    int b = log("field b");
    Widget() {
        log("constructor");
    }
    static int log(String msg) {
        System.out.println("Running: " + msg);
        return 0;
    }
}
new Widget();

Output

Running: field a
Running: instance initializer
Running: field b
Running: constructor