java - 为什么Java中变量必须初始化为默认值

Question

在一篇关于如何在 Java 中初始化对象的文章中有一段如下:

At the beginning of an object's life, the Java virtual machine (JVM) allocates enough memory on the heap to accommodate the object's instance variables. When that memory is first allocated, however, the data it contains is unpredictable. If the memory were used as is, the behavior of the object would also be unpredictable. To guard against such a scenario, Java makes certain that memory is initialized, at least to predictable default values, before it is used by any code.

任何人都可以在这里解释一下不可预测的数据和不可预测的行为是什么意思。提前致谢

Answer 1

Can anyone kindly explain that what is meant by unpredictable data and unpredictable behavior here.

如果您使用 C/C++ 编程，您会注意到未初始化的变量带有一些垃圾值，存在于分配给它的内存位置，根据变量的数据类型进行解释。编译器不会提示此类变量，如果开发人员忘记正确初始化它们，就会使用垃圾值，从而导致程序出现意外行为。

在 Java 中，JVM 根据变量的数据类型将所有成员变量初始化为默认值，并在编译期间提示未初始化的局部变量，以避免此类意外行为并使开发人员始终使用已初始化的变量。