Windows 忽略 JAVA_HOME：如何将 JDK 设置为默认值？

Question

How do I persuade Windows to use the JDK instead of a JRE?

This question has been asked before, here and elsewhere:

How do I set the default Java installation/runtime (Windows)?

The trouble is that Windows ignores JAVA_HOME and it also ignores the fact that I made the JDK bin directory the first entry in the path.

When I run java -version from the command line, instead of invoking my JDK 1.6 installation, it runs the 1.7 JRE.

My guess is that this is a problem specific to 1.7, and Windows 7 is doing something it shouldn't with the registry.

Any ideas on how to fix this?

Edit : Oops. I wrote "first entry in the classpath" above, when I meant "path". Sorry.

Answer 1

On Windows, the same java executable can load DLLs for different versions of Java. It looks at the directory from which it's running to see if it contains libraries for a particular version of Java. If not, it uses the Windows Registry to locate the default version of Java for the system.

The Java installer will put a copy of java.exe (but no libraries) in the the Windows\system32 C:\Program Files (x86)\Common Files\Oracle\Java\javapath directory, and add that directory to the beginning of the PATH variable.

If you don't use a full path, the copy of java.exe to run is found by using the PATH system variable. Since this directory doesn't contain the DLLs of a particular Java runtime version, one is located one by looking at the registry.

So, you either need to modify the registry, or replace the javapath entry with the version of Java you want in your PATH system (not user) variable.

Answer 2

In Windows 8, you may want to remove C:\ProgramData\Oracle\Java\javapath directory.

from path

It solved my issue.

Answer 3

I have this issue too. I am running 1.6 but want to build the code I'm working on with 1.5. I've changed the JAVA_HOME and PATH (both user and system) to no avail.

The answer is that the installer for 1.6 dropped java.exe , javaw.exe , and javaws.exe into my Windows\System32 folder (Windows 7).

I solved it by renaming those files to java_wrong.exe , javaw_wrong.exe , and javaws_wrong.exe . Only after doing that does it pick up the correct version of java as defined in JAVA_HOME and PATH . I renamed the files thusly because that deleted them in an easily reversible manner.

Hope this helps!

Answer 4

Windows doesn't ignore anything. This is an issue with your setup; Windows just uses what you provide. It has no special knowledge of JAVA_HOME .

CLASSPATH has nothing to do with Windows, either. To Windows it's only an environmental variable that gets expanded to a folder location.

Check your %PATH% environmental variable. It's what's making Windows find one before the other. The path (as the post you linked to said) should point to %JAVA_HOME%\bin;<remainder of path> . Again, the post you linked to gave you a way to set this using a batch file.

(For others who might not know this: The easiest way to inspect the %PATH% is to open a command prompt and type echo %PATH% . You can also get there by right-clicking on Computer in the right pane of the Start Menu and choosing Properties , then Advanced System Settings , and the tne Environmental Variables button.)

Answer 5

I had the same issue. I have a bunch of Java versions installed and for some reason Java 1.7 was being used instead of Java 1.6, even though I specified in the path to use 1.6 (C:\jdk1.6.0_45_32\bin).

I had to move the path of the JDK I wanted to use (1.6) to be the first entry in the PATH environment variable to make sure Windows uses 1.6 instead of 1.7.

So, for example, the PATH environment variable before was:

C:\Program Files (x86);...<other entries>;C:\dev\ant181\bin;C:\jdk1.6.0_45_32\bin

and after I moved the jdk to be first, it worked:

C:\jdk1.6.0_45_32\bin;C:\Program Files (x86);...<other entries>;C:\dev\ant181\bin

I guess the Windows installer of Java 1.7 installed it to some other directory already in the PATH, thus getting used first instead of the specified custom PATH entry C:\jdk1.6.0_45_32\bin;

Answer 6

Suppose you have install JDK 10 after JDK 8 and in the system environment variable set path like "C:\ProgramData\Oracle\Java\javapath" then Java version control by this path. it will ignore JAVA_HOME even jdk 1.8 path set here So remove "C:\ProgramData\Oracle\Java\javapath" in path to get effect of JAVA_HOME path

Answer 7

For my Case in 'Path' variable there was a parameter added like ' C:\ProgramData\Oracle\Java\javapath; '. This location was having java.exe , javaw.exe and javaws.exe from java 8 which is newly installed via jdk.exe from Oracle.

I've removed this text from Path where my Path already having %JAVA_HOME%\bin with it.

Now, the variable 'JAVA_HOME' is controlling my Java version which is I wanted.

Answer 8

I had Java 7 and 8 installed and I want to redirect to java 7 but the java version in my cmd prompt window shows Java 8.
Added Java 7 bin directory path ( C:\Program Files\Java\jdk1.7.0_10\bin ) to PATH variable at the end, but did not work out and shows Java 8. So I changed the Java 7 path to the starting of the path value and it worked.
Opened a new cmd prompt window and checked my java version and now it shows Java 7

Answer 9

将 Path 环境变量设置为所需的 jdk/bin 目录

Answer 10

In my case I had Java 7 and 8 (both x64) installed and I want to redirect to java 7 but everything is set to use Java 8. Java uses the PATH environment variable:

C:\ProgramData\Oracle\Java\javapath

as the first option to look for its folder runtime (is a hidden folder). This path contains 3 symlinks that can't be edited.

In my pc, the PATH environment variable looks like this:

C:\ProgramData\Oracle\Java\javapath;C:\Windows\System32;C:\Program Files\Java\jdk1.7.0_21\bin;

In my case, It should look like this:

C:\Windows\System32;C:\Program Files\Java\jdk1.7.0_21\bin;

I had to cut and paste the symlinks to somewhere else so java can't find them, and I can restore them later.

After setting the JAVA_HOME and JRE_HOME environment variables to the desired java folders' runtimes (in my case it is Java 7), the command java -version should show your desired java runtime. I remark there's no need to mess with the registry.

Tested on Win7 x64.

Answer 11

This issue is probably because of the earlier versions of Java installed in your System. First check your Environment Variables Carefully and remove all the Environment Variables related to the previous versions of JAVA and replace those paths to

C:\Program Files\Java\<your new jdk version>\bin

Answer 12

There's an additional factor here; in addition to the java executables that the java installation puts wherever you ask it to put them, on windows, the java installer also puts copies of some of those executables in your windows system32 directory, so you will likely be using which every java executable was installed most recently.

Answer 13

以防万一您将 .BAT 文件用作 Windows 服务，我建议您卸载 Windows 服务并在更改 %JAVA_HOME% 以指向正确的 Java 版本后重新安装它。

Answer 14

After struggling with this issue for some time and researching about it, I finally managed to solve it following these steps:

1) install jdk version 12
2) Create new variable in systems variable
3) Name it as JAVA_HOME and give jdk installation path
4) add this variable in path and move it to top.
5) go to C:\Program Files (86)\Common Files\Oracle\Java\javapath and replace java.exe and javaw.exe with the corresponding files with the same names from the pathtojavajdk/bin folder

Finally, I checked the default version of java in cmd with "java -version" and it worked!

Answer 15

I had the same problem, in user environment variable settings I was having JAVA_HOME and PATH configured properly but it didn't work. As I update my system environment variables then it started to work.

Answer 16

I was facing the same issue. I had a java version of 8.11. I had these two in my path: C:\Program Files\Java\jdk1.8.0_51\bin and C:\ProgramData\Oracle\Java\javapath

What I did is that I had changed the jdk to %JAVA_HOME%\bin like this and renamed the directory ( C:\ProgramData\Oracle\Java\javapath ) of javapath to javapath1 and it resolved my problem.

Answer 17

Delete C:\ProgramData\Oracle\Java\javapath from Path in system variables & add your custom value for JAVA_HOME variable for User variables. This will work in Windows 10.

Answer 18

Folks who responded by stating setting PATH variable should work then please explain this:

You need to remove the entry C:\Program Files (x86)\Common Files\Oracle\Java\javapath from PATH and make sure you have %JAVA_HOME%\bin entry under PATH and JAVA_HOME defined.