JDK 7将自身报告为JRE（通过“java.home”系统属性）(JDK 7 reports itself as a JRE (via “java.home” system property))

 我刚刚安装了最新的JDK 7 Update 21并编写了以下单行程序（在Windows 7上）： 
 
public static void main(String[] args) {
    System.out.println("java.home = " + System.getProperty("java.home"));
}
 
 输出（令人惊讶）： 
 
java.home = D:\Java\jdk1.7.0_21\jre
 
 我相信我解决了所有常见原因： 
 
 
 
 JAVA_HOME设置为“D：\ Java \ jdk1.7.0_21” 
 
 
 我已将“D：\ Java \ jdk1.7.0_21 \ bin”设置为系统PATH设置中的第一个路径。 
 
 
 Windows \ System32中没有java.exe 
 
 
 我正在使用“新鲜”的命令行 
 
 
 我已广泛搜索此网站和其他网站 
 
 
 我的注册表不包含“HKEY_LOCAL_MACHINE \ SOFTWARE \ JavaSoft \ Java运行时环境”键。 “HKEY_LOCAL_MACHINE \ SOFTWARE \ JavaSoft \ Java Development Kit \ 1.7”的值包含正确的“JavaHome”值。 
 
 
 在java.exe调用中添加“-server”选项不会更改输出 
 
 
 以下是您的信息的更多输出 
 
D:\Temp>echo %PATH%
d:\Java\jdk1.7.0_21\bin

D:\Temp>echo %JAVA_HOME%
D:\Java\jdk1.7.0_21

D:\Temp>type SystemInfo.java
public class SystemInfo {

        public static void main(String[] args) {
                System.out.println("java.home = " + System.getProperty("java.home"));
        }

}

D:\Temp>java -verbose SystemInfo
[Opened d:\Java\jdk1.7.0_21\jre\lib\rt.jar]
[Loaded java.lang.Object from d:\Java\jdk1.7.0_21\jre\lib\rt.jar]
[Loaded java.io.Serializable from d:\Java\jdk1.7.0_21\jre\lib\rt.jar]
...
[Loaded java.lang.Void from d:\Java\jdk1.7.0_21\jre\lib\rt.jar]
java.home = d:\Java\jdk1.7.0_21\jre
[Loaded java.lang.Shutdown from d:\Java\jdk1.7.0_21\jre\lib\rt.jar]
[Loaded java.lang.Shutdown$Lock from d:\Java\jdk1.7.0_21\jre\lib\rt.jar]
 
 （更新:) 基本上我需要知道，如何运行我的Java应用程序，以便它可以访问java编译器（在JDK的tools.jar中找到），而无需将JAR复制到其他地方。 
 
 顺便说一下，这背后的主要问题是我的码头无法编译JSP，因为缺少java编译器。 我知道我可以将“tools.jar”添加到JRE \ lib \ ext，但这不是一个长期的解决方案。 

I just installed the latest JDK 7 Update 21 and wrote the following one-liner (on Windows 7):
 
public static void main(String[] args) {
    System.out.println("java.home = " + System.getProperty("java.home"));
}
 
the output is (surprisingly):
 
java.home = D:\Java\jdk1.7.0_21\jre
 
I believe I fixed all the common causes:
 
 
 
JAVA_HOME is set to "D:\Java\jdk1.7.0_21"
 
 
I have set "D:\Java\jdk1.7.0_21\bin" as the first path in the system PATH setting.
 
 
There is no java.exe in Windows\System32
 
 
I am using a "fresh" command-line
 
 
I have searched this and other sites extensively
 
 
My registry does not contain a "HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment" key. The value of "HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Development Kit\1.7" contains a correct "JavaHome" value.
 
 
Adding "-server" option to the java.exe call does not change the output
 
 
Here is some more output for your information
 
D:\Temp>echo %PATH%
d:\Java\jdk1.7.0_21\bin

D:\Temp>echo %JAVA_HOME%
D:\Java\jdk1.7.0_21

D:\Temp>type SystemInfo.java
public class SystemInfo {

        public static void main(String[] args) {
                System.out.println("java.home = " + System.getProperty("java.home"));
        }

}

D:\Temp>java -verbose SystemInfo
[Opened d:\Java\jdk1.7.0_21\jre\lib\rt.jar]
[Loaded java.lang.Object from d:\Java\jdk1.7.0_21\jre\lib\rt.jar]
[Loaded java.io.Serializable from d:\Java\jdk1.7.0_21\jre\lib\rt.jar]
...
[Loaded java.lang.Void from d:\Java\jdk1.7.0_21\jre\lib\rt.jar]
java.home = d:\Java\jdk1.7.0_21\jre
[Loaded java.lang.Shutdown from d:\Java\jdk1.7.0_21\jre\lib\rt.jar]
[Loaded java.lang.Shutdown$Lock from d:\Java\jdk1.7.0_21\jre\lib\rt.jar]
 
(Updated:) Basically I need to know, how to run my java application so that it has access to the java-compiler (found in the JDK's tools.jar) without copying that JAR to some other place.
 
BTW the main problem behind this is that my jetty can't compile a JSP since the java-compiler is missing. I know I can add "tools.jar" to JRE\lib\ext but thats not a long-term solution.

原文：https://stackoverflow.com/questions/17061482