无法在 Windows 中更改 Java 版本

Question

Previously I am using Java 1.8 in my machine. But now i need to use Java 1.6 . So I changed the below values in system environment variables .

JAVA_HOME

U:\POC\jdk1.6.0_31

PATH

U:\POC\jdk1.6.0_31\bin\ or %JAVA_HOME%/bin

Also I restarted my system

Even after that it is displaying java version as 1.8 in my command prompt.

Can anyone advice on how to resolve this issue?

Answer 1

when latest version is installed in system it automatically set javapath in environment variable like "C:\\ProgramData\\Oracle\\java\\javapath". Remove this from environment variables.

Answer 2

This suggestion may seem obvious, but I urge you to carefully consider this advice.

I have encountered this issue before, and frequently, it has been due to an overlooked entry within the long list of items making up the Windows Path. It is often an path entry where it is not immediately obvious that any of the java executables (javaw.exe, javaw.exe or javaws.exe) may reside. A common culprit is C:\\ProgramData\\Oracle\\Java\\javapath

You will therefore need to push upwards, your desired java/bin path above these. If in doubt, push it right to the top!

In the unlikely event that this does not work, then try making changes from within the java admin console (Control Panel --> Java --> Java tab --> View Button).

Answer 3

I've not used Windows in a long time but I remember that there are 2 sections of environment variables. One system scope, and the other user scope.

1. Check that nothing in the system scope is defining a JAVA_HOME .
2. Like @Stephen C said, post the output of echo %PATH% and echo %JAVA_HOME% .
3. Check that nothing comes before %JAVA_HOME%/bin in the path that may contain the java executable. Things like Oracle client come with Java. You can always put %JAVA_HOME%/bin in front of the path instead of at the end.

@David Santiago's answer is a bad idea. If you let the IDE do your job, you won't be able to troubleshoot when there is a problem.

Answer 4

The system displays the latest version installed on the system. That's informative only, that should not worry you.

If you are going to use version 6.0_31 of the Java JDK you only have to configure that in your IDE (Eclipse, Netbeans, IntelliJ IDEA, whatever) to compile using that version.

Example

Answer 5

I recently ran into this as I have added in JAVA 9, 11, and 17 along with my previous JAVA 6, and 8 versions.
I incorrectly assumed that env variables hadn't changed with the newer releases, but I was obviously wrong.

When I ran java -version it returned JAVA 9 and javac -version returned JAVA 17. So, I incorrectly tried to add a %JAVA_HOME% variable, as I had always done in pre-JAVA 8 versions under the Windows Environment Settings. However, despite moving that addition to the front of the PATH, it didn't change anything!

This article explains the issue: Java SE 8 Update 171 Uses Different Windows Path (Doc ID 2412304.1) , however it doesn't give any solutions.

The path to this Windows folder is:

C:\ProgramData\Oracle\Java\javapath

Notice is under a ProgramData folder, not Program Files. Moreover, it has been prepended to PATH under the Windows env settings. This folder is where java has 3 symbolic links set that will override the PATH changes you make and sure enough it was pointing to the JAVA versions I returned from -version on java and javac. Even if I tried to set a JAVA_HOME as the first entry in path, it still didn't work!

I found two solutions here at: JDK 8 and C:\ProgramData\Oracle\Java\javapath

How to switch JDK version in cmd more flexibly You can either prepend your own directory to the PATH to overwrite the Oracle one, or follow the convention to append to the end of PATH variable like always did. I prefer the second one, here is how to do it.

The second solution uses two batch files with a env variable JAVA_HOME setting similar to what I had always used.

Answer 6

On command prompt use these commands to set envirnment variables

JAVA_HOME=C:\Program Files\Java\jdk-11.0.17

set PATH=%JAVA_HOME%\bin;%PATH%