Java中的双重检查锁定问题[duplicate]

其中一篇文章提到了 "Double Check Locking"

public class MyBrokenFactory {
  private static MyBrokenFactory instance;
  private int field1, field2 ...

  public static MyBrokenFactory getFactory() {
    // This is incorrect: don't do it!
    if (instance == null) {
      synchronized (MyBrokenFactory.class) {
        if (instance == null)
          instance = new MyBrokenFactory();
      }
    }
    return instance;
  }

  private MyBrokenFactory() {
    field1 = ...
    field2 = ...
  }
}

原因:- (请注意编号顺序)

Thread 1: 'gets in first' and starts creating instance.

1. Is instance null? Yes.
2. Synchronize on class.
3. Memory is allocated for instance.
4. Pointer to memory saved into instance.

[[Thread 2]]

7. Values for field1 and field2 are written
to memory allocated for object.

.....................
Thread 2: gets in just as Thread 1 has written the object reference
to memory, but before it has written all the fields.

5. Is instance null? No.
6. instance is non-null, but field1 and field2 haven't yet been set!
   This thread sees invalid values for field1 and field2!

问题:
由于新实例(new MyBrokenFactory())的创建是从synchronized块完成的,那么在整个初始化完成之前(private MyBrokenFactory()完全执行)是否会释放锁?

https://www.javamex.com/tutorials/double_checked_locking.shtml

请解释一下。