java - 我们可以假设 Java 中的默认数组值吗？例如，假设一个 int 数组设置为全零？

Question

在实践中，我可以假设 Java 中的所有 int 数组都以零填充开始吗？对于所有运行 JVM 的机器？

这适用于所有类型吗？字符？ boolean 值？枚举？

官方记录在哪里？

我说过的教科书将 int 数组设置为零，但他们也建议应该编写一个 for 循环将所有值设置为零只是“更清楚”。

Answer 1

Java Language Specification是寻找此类信息的正确位置:

Array components are unnamed variables that are created and initialized to default values (§4.12.5) whenever a new object that is an array is created

默认值本身在 section 4.12.5 中给出.

• For type byte, the default value is zero, that is, the value of (byte)0.
• For type short, the default value is zero, that is, the value of (short)0.
• For type int, the default value is zero, that is, 0.
• For type long, the default value is zero, that is, 0L.
• For type float, the default value is positive zero, that is, 0.0f.
• For type double, the default value is positive zero, that is, 0.0d.
• For type char, the default value is the null character, that is, '\u0000'.
• For type boolean, the default value is false.
• For all reference types, the default value is null.