java - 即使JDK包含JRE，还需要JRE吗？

Question

这个问题已经有答案了:

What is the difference between JDK and JRE? (20 个回答)

已关闭 5 年前。

抱歉，如果这些是非常愚蠢的问题，因为我是java新手。JDK内部包含了JRE，那么如果是一个独立的应用程序，还需要JRE吗？

Answer 1

并不是每个人都想构建 Java 应用程序(这是 JDK 的用途)。许多人只是想运行它们(这是 JRE)，例如获得 JAR 文件的最终用户。

例如:在我的国家，电子报税是通过 Java 应用程序完成的。用户需要 JRE 来运行程序(他们可以在其中填写和提交表单)，但不需要整个 JDK。

编辑:根据OP的评论，真正的问题是为什么JDK包含一个额外的JRE。我做了一些研究，发现Oracle's explanation :

Private Versus Public JRE

Installing the JDK also installs a private JRE and optionally a public copy.

The private JRE is required to run the tools included with the JDK. It has no registry settings and is contained entirely in a jre directory (typically at C:\Program Files\jdk1.7.0\jre) whose location is known only to the JDK.

On the other hand, the public JRE can be used by other Java applications, is contained outside the JDK (typically at C:\Program Files\Java\jre1.7.0), is registered with the Windows registry (at HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft), can be removed using Add/Remove Programs, might be registered with browsers, and might have the java.exe file copied to the Windows system directory (which would make it the default system Java platform).