如果实例初始值设定项不引用其类的任何非 static 成员，则可以为 static。 Static initializers are executed once when the class is resolved, while instance initializers are executed on each instantiation of the class.

此检查不报告匿名类中的实例空初始值设定项和初始值设定项。

示例：

  class A {
     public static String CONSTANT;
     {
        CONSTANT = "Hello";
     }
  }

在应用快速修复后：

  class A {
     public static String CONSTANT;
     static {
        CONSTANT = "Hello"; // 现在每个类仅实例化一次
     }
  }