Java Initialization Order

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Code

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public class Main {
    public static void main(String... args) {
        new Out("Main start\n");
        new Out("Before new a B object");
        new Out();
        new B();
        new Out();
        new Out("After new a B object");
        new Out("");
        new Out();
        new Out(C.constCvar);
        new Out();
        new Out(C.staticCVar);
        new Out();
        new Out("Before new a C object");
        new Out();
        new C();
        new Out();
        new Out("After new a C object");
        new Out("");
        new Out("Main end");
    }
}

class Out {
    public Out() {
        System.out.println("-------------------------");
    }

    public Out(String message) {
        System.out.println(message);
    }
}


class A {
    public static Out o1 = new Out("A static member o1 initialize");
    public Out o2 = new Out("A member o2 initialize");

    { new Out("A non-static block execute"); }

    static { new Out("A static block execute"); }

    public A() { new Out("A constructor execute"); }
}

class B extends A {
    public static Out o3 = new Out("B static member o3 initialize");
    public Out o4 = new Out("B member o4 initialize");

    { new Out("B non-static block execute"); }

    static { new Out("B static block execute"); }

    public B() { new Out("B constructor execute"); }
}

class C {
    public static final String constCvar = "const C member";
    public static String staticCVar = "static C member";

    static { new Out("C static block execute"); }

    public C(){ new Out("C constructor execute"); }

}

Output

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Main start

Before new a B object
-------------------------
A static member o1 initialize
A static block execute
B static member o3 initialize
B static block execute
A member o2 initialize
A non-static block execute
A constructor execute
B member o4 initialize
B non-static block execute
B constructor execute
-------------------------
After new a B object

-------------------------
const C member
-------------------------
C static block execute
static C member
-------------------------
Before new a C object
-------------------------
C constructor execute
-------------------------
After new a C object

Main end