在Java安装目录中，为什么有多个java.exe文件？

Question

Just curious about the directory layout for the JDK . So there are two separate java.exe files - one is in:

C:\Program Files (x86)\Java\jdk1.7.0_45\bin

and one is in:

C:\Program Files (x86)\Java\jdk1.7.0_45\jre\bin

Why does there need to be two files ? The motivation for this question arises from some challenge I'm having installing a program(SQL Developer).

Answer 1

There's a difference between installing the jdk vs. the jre .

The jdk package is the developer package and includes tools such as the compiler ( javac ).

The jre package is the core runtime package, and includes the JVM / runtime environment / whatever you need to run software written in JVM languages.

Answer 2

Here a link to the official Oracle documentation.

The binaries in jdk/bin and jdk/jre/bin are identical. According to the documentation, the PATH should point to jdk/bin .

Answer 3

Here is a link to JDK 7 and JRE 7 Installation Guide

If you want to run Java programs, but not develop them, download the JRE. If you want to develop Java applications, download the Java Development Kit, or JDK. The JDK includes the JRE, so you do not have to download both separately.