类初始化顺序问题，final修饰属性影响加载顺序

测试1：

public class Demo{ public Demo(){ System.out.println("create demo object"); } public static String str = "abcd"; static { System.out.println("init static block."); } } public class Test1{ public static void main(String... args){ String a = Demo.str; System.out.println(a); } }

结果1：

init static block. abcd

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测试2：

public class Demo2{ public Demo(){ System.out.println("create demo object"); } public static final String str = "abcd"; static { System.out.println("init static block."); } } public class Test2{ public static void main(String... args){ String a = Demo.str; System.out.println(a); } }

结果2：

abcd

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测试3：

public class Demo3{ public Demo(){ System.out.println("create demo object"); } public static final String str = new String("abcd"); static { System.out.println("init static block."); } } public class Test3{ public static void main(String... args){ String a = Demo.str; System.out.println(a); } }

结果3： 编译时候不能确认a值，只有在运行时才赋予a值

init static block. abcd

问题： 有final和没有final修饰，初始化不一样，怎么理解？？