javac version and java version show different on command line

问题

Before, I had java 8. I recently installed java 11. I moved my path Java\jdk-11.0.7\bin to the top of my environment variables. When I do javac -version it gives me version 11. But when I do java -version, it gives me version 8. How do I correct this? Specifically, I want to run a jar file that was compiled using java 11.

回答1:

Whenever you install JDK, it asks for the path of JRE as well. There is a possibility that you mentioned a different path for JRE than the JAVA_HOME or opted out the installation. If that happened, you should uninstall both, Java 8 and Java 11 and then install Java 11 again. However, before you do this, you can try/ensure the following things:

1. If you have put the PATH as %JAVA_HOME%\bin, it won't work if the installation path (i.e. the path of JAVA_HOME) has space. In such a case, you need to put the absolute path instead of %JAVA_HOME%\bin in the PATH environment variable.
2. Try the commands in a new cmd window.
3. Restart the system.
4. Move the path of JDK bin to the top in both, User variables as well as System variables.

回答2:

In linux distors you can configure java and javac with

update-alternatives --config java
update-alternatives --config javac

来源：https://stackoverflow.com/questions/61644958/javac-version-and-java-version-show-different-on-command-line