Update jdk and old workspace still points to the stale JRE system libraries

[testforstephen]

Steps to reproduce:

1. Install jdk1.8.0_131 in windows 10, and set JAVA_HOME and Path environment variables.

2. Install latest vscode-java extension in vscode, and open a java 8 maven project.

3. F12 at java.io.PrintStream.println, jump to editor contents/rt.jar/java.io/PrintStream.class.

4. Install the latest jdk-9.0.1 and update JAVA_HOME and Path environment variables.

5. Restart vscode window.

6. F12 at java.io.PrintStream.println, still jump to the stale jre source contents/rt.jar/java.io/PrintStream.class. It's supposed to jump to the java 9 source contents/java.base/java.io/PrintStream.class.

Actually the java language server was launched by the new java 9 jvm, but the workspace cached the old JRE 8 system libraries and user has no way to change the JRE system libraries.

Current workaround is to clean up the vscode local storage directory C:\Users\jinbwan\AppData\Roaming\Code - Insiders\User\workspaceStorage.

Expected: When vscode-java extension startup, update the workspace jre container to the one under JAVA_HOME silently. Or provide a command to allow user to update the workspace JRE container.

[ikbalsingh]

Current Workaround for Ubtuntu (cleared .config/Code/User/workspace) not working.

[snjeza]

If there are JDK8 and JDK9 in the workspace, Java LS will configure a project's JRE based on the project settings. If you want to use JDK9, you should add:

<plugin>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.7.0</version>
    <configuration>
        <source>9</source>
        <target>9</target>
    </configuration>
</plugin>

to your pom.xml

@fbricon We can remove all JREs except a JRE defined with the java.home property.

[fbricon]

as a best practice, you should prefer <release> over the <source>+<target> combo, since the compiler will check no unavailable APIs will be leaked during compilation. Only works for Java9+ projects though.

<plugin>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.7.0</version>
    <configuration>
        <release>9</release>
    </configuration>
</plugin>

@snjeza not sure about removing other JREs. You still need to be able to switch between JDK easily, eg. 1.8 -> 9. I need to think about it.

[fbricon]

@testforstephen is this still an issue?

[13rac1]

• vscode: 1.77.1
• Extension Pack for Java: v0.25.1
• Language Support for Java(TM) by Red Hat: v1.16.0
• Gradle for Java v3.12.7

Just encountered this issue or a similar issue. Upgraded a project from 11 to 17. Gradle Tasks vscode-gradle worked with 17, but the vscode-java tooling continued to use Java 11. All settings were ignored: https://github.com/redhat-developer/vscode-java#setting-the-jdk The workaround above worked. I deleted the workspace storage and everything was fine:

rm -rf ~/.config/Code/User/workspaceStorage