VS Code & WSL2 - 将 Java 语言级别指定为 1.8

Question

I'm using VS Code in WSL2 and have installed a bunch of Java Extensions as per this link - normal Java programs work well - able to Run & Debug from VS Code.

Although when I start using Java 8 specific features like Lambda, it starts complaining about the source level for Java

I've the following environment variables configured for Java Home

What property should be specified in Settings to determine the source level as 1.8 and not lower !

Edit: The bottom blue bar says the current Java Runtime is J2SE1.5 for some reason. See Attached

On clicking, it asks to add the following property: java.configuration.runtimes and so I've added the following in my WSL2 settings for VS Code - still no effect !

"java.configuration.runtimes": [
{
  "name": "JavaSE-1.8",
  "path": "/usr/lib/jvm/zulu-8-amd64",
  "default": true
}

]

Answer 1

Got my answer from Gitter that it picks up the language level settings from build file of the project. So I added a basic POM file with proper source & target config for maven-compiler-plugin and restarted IDE. Voila, it works !

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
    <source>${maven.compiler.source}</source>
    <target>${maven.compiler.target}</target>
</configuration>

Answer 2

I think if you use jdk 11 or later, you maybe find that no matter how you configure settings.json file, the language level never change.

The problem is eclipse's setttings. in ${WorkSpaceRoot}\.setting\org.eclipse.jdt.core.prefs , there are 3 settings: targetPlatform , compliance , source , need to change to 1.8 or later version.

And in .classpath file:

<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8">

you can see there's a JavaSE-1.8 , you can change it to other version(which should meets the eclipse settings).

Also there's a quick way to do this: vscode can search in the workspace to find the number(in your case is 1.5 ), and replace them.

Answer 3

I use the spring framework with gradle, lombok plugin and skdman (aside gradle, for maven is as good as well, I recommend use'em, they are all great), but I believe my configurations can be useful for everyone, so here it goes...

One thing I may add thought its I got strange errors using plugins with command line gradle wich was corrected when i start using the vscode plugins interfaces only, therefor i would recommend give it a try and use the plugins buttons, if you have not done it yet.

At launch.json I have the following debug configurations:

{
  "name": "Spring Project ???",
  "type": "java",
  "request": "launch",
  "cwd": "${workspacefolder}",
  "console": "internalConsole",
  "mainClass": "br.com.meuProject.???",
  "projectName": "???",
  "args": []
}

• Note that the cwd is like workspacefolder, but you can change it to other values like fileDirname, however in these cases it may be legal to also define the value of the variable "program"

In settings.json I have the following environment settings:

"java.semanticHighlighting.enabled": true,
"java.configuration.checkProjectSettingsExclusions": false,
"java.home": "C:\\Users\\name\\.sdkman\\candidates\\java\\current",
"java.jdt.ls.vmargs": "-XX:+UseParallelGC -XX:GCTimeRatio=4 -XX:AdaptiveSizePolicyWeight=90 -Dsun.zip.disableMemoryMapping=true -Xmx1G -Xms100m -javaagent:\"/home/user/.vscode/extensions/gabrielbb.vscode-lombok-1.0.1/server/lombok.jar\"",

• Note "java.home" defines you're JAVA_HOME variable.
• Note "java.jdt.ls.vmargs" defines the variables passed to command line whenever building java.

Hope to be of some use. Cheers!

Answer 4

In my case I had to configure my java runtime which is using java 7. (view -> command palette -> configure java runtime). Here change java version to java 8 or later.