With this example we are going to demonstrate what happens when there are changes in the initialization order of classes. The steps of the example are described in short:
- We have created class
A, with a constructor that gets an int val and prints it. - We have also created class
Cr. - In the
Crwe use theAconstructor to create three newAobjectsa,a2anda3. In theCrconstructor we reinitializea3object.Cralso has a methodfunction(). - We create a new instance of
Crcalling its constructor. All threea,a2,a3objects are initialized and thena3is reinitialized in theCrconstructor.
Let’s take a look at the code snippet that follows:
package com.javacodegeeks.snippets.core;
class A {
A(int val) {
System.out.println("A(" + val + ")");
}
}
class Cr {
A a = new A(1); // Before constructor
Cr() {
// Indicate we're in the constructor:
System.out.println("Cr()");
a3 = new A(33); // Reinitialize t3
}
A a2 = new A(2); // After constructor
void function() {
System.out.println("function()");
}
A a3 = new A(3); // At end
}
public class InitializationOrder {
public static void main(String[] args) {
Cr t = new Cr();
t.function(); // Shows that construction is done
}
}
Output:
A(1)
A(2)
A(3)
Cr()
A(33)
function()
This was an example of what happens when there are changes in the initialization order of classes in Java.
