Java 实际上不必安装。您可以运行任何可用的 Java。
这有时对于从网络共享运行 Java 很有用。
尝试通过完全限定java.exe 程序来运行它。如果它以这种方式运行,则问题出在您的PATH。
为了说明您可以通过限定它来运行任何 Java,我安装了 9 个 JDK 和 1 个 JRE:
- 32 位 JDK:版本 1.4、5、6、7 和 8
- 64 位 JDK:版本 5、6、7 和 8
- 32 位 JRE:版本 8
从单个命令提示符窗口复制:
C:\>"C:\prog\java32\jdk1.4.2_19\bin\java.exe" -version
java version "1.4.2_19"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_19-b04)
Java HotSpot(TM) Client VM (build 1.4.2_19-b04, mixed mode)
C:\>"C:\prog\java32\jdk1.5.0_22\bin\java.exe" -version
java version "1.5.0_22"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_22-b03)
Java HotSpot(TM) Client VM (build 1.5.0_22-b03, mixed mode)
C:\>"C:\prog\java32\jdk1.6.0_45\bin\java.exe" -version
java version "1.6.0_45"
Java(TM) SE Runtime Environment (build 1.6.0_45-b06)
Java HotSpot(TM) Client VM (build 20.45-b01, mixed mode, sharing)
C:\>"C:\prog\java32\jdk1.7.0_79\bin\java.exe" -version
java version "1.7.0_79"
Java(TM) SE Runtime Environment (build 1.7.0_79-b15)
Java HotSpot(TM) Client VM (build 24.79-b02, mixed mode, sharing)
C:\>"C:\prog\java32\jdk1.8.0_51\bin\java.exe" -version
java version "1.8.0_51"
Java(TM) SE Runtime Environment (build 1.8.0_51-b16)
Java HotSpot(TM) Client VM (build 25.51-b03, mixed mode)
C:\>"C:\prog\java64\jdk1.5.0_22\bin\java.exe" -version
java version "1.5.0_22"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_22-b03)
Java HotSpot(TM) 64-Bit Server VM (build 1.5.0_22-b03, mixed mode)
C:\>"C:\prog\java64\jdk1.6.0_45\bin\java.exe" -version
java version "1.6.0_45"
Java(TM) SE Runtime Environment (build 1.6.0_45-b06)
Java HotSpot(TM) 64-Bit Server VM (build 20.45-b01, mixed mode)
C:\>"C:\prog\java64\jdk1.7.0_79\bin\java.exe" -version
java version "1.7.0_79"
Java(TM) SE Runtime Environment (build 1.7.0_79-b15)
Java HotSpot(TM) 64-Bit Server VM (build 24.79-b02, mixed mode)
C:\>"C:\prog\java64\jdk1.8.0_51\bin\java.exe" -version
java version "1.8.0_51"
Java(TM) SE Runtime Environment (build 1.8.0_51-b16)
Java HotSpot(TM) 64-Bit Server VM (build 25.51-b03, mixed mode)
C:\>"C:\Program Files (x86)\Java\jre1.8.0_51\bin\java.exe" -version
java version "1.8.0_51"
Java(TM) SE Runtime Environment (build 1.8.0_51-b16)
Java HotSpot(TM) Client VM (build 25.51-b03, mixed mode, sharing)