Incorrect java version getting picked up

[2598Nitz]

Seems like vscode-spring-initializr defaults to latest java version, which is 17 as of today. I had selected java version 8. Since, jdk on my local machine is of java 8 and compiled class downloaded by vscode-spring-initialize is of java 17, I was not able to run SpringBootApplication class.

[Eskibear]

and compiled class downloaded by vscode-spring-initialize is of java 17

This extension doesn't download compiled classes at all. It simply generates a spring boot project.

<java.version>8</java.version>

Check whether java.version is set to 8 in your pom.xml, after the project is created by this extension. If so, then nothing is wrong with this extension.

[2598Nitz]

java.version is 8 in pom.xml file.

Here's the error that I get when I run spring boot application:

/usr/bin/env /usr/lib/jvm/java-8-openjdk-amd64/bin/java -cp /tmp/cp_cspnamolxupwt2er09kr4mtub.jar com.example.demo.DemoApplication
Exception in thread "main" java.lang.UnsupportedClassVersionError: org/springframework/boot/SpringApplication has been compiled by a more recent version of the Java Runtime (class file version 61.0), this version of the Java Runtime only recognizes class file versions up to 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:756)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:473)
at java.net.URLClassLoader.access$100(URLClassLoader.java:74)
at java.net.URLClassLoader$1.run(URLClassLoader.java:369)
at java.net.URLClassLoader$1.run(URLClassLoader.java:363)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:362)
at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
at com.example.demo.DemoApplication.main(DemoApplication.java:10)

I didn't get this error, when I manually downloaded project from spring initializr website.

[2598Nitz]

This problem seems to be due to combination of spring boot version 3.0.0 and java version 8 being incompatible.
https://stackoverflow.com/questions/73679679/java-cannot-access-org-springframework-boot-springapplication-bad-class-file

When I downloaded manually with same combination, the downloaded starter project had java version overriden to 17 which explains why I was able to run the application.

Potentially, vscode-spring-initializr can have a feature to detect incompatible spring boot and java version.

[Eskibear]

When I downloaded manually with same combination, the downloaded starter project had java version overriden to 17 which explains why I was able to run the application.

Confirmed the behavior. We use the same endpoint to download the project. Looks like the params are different.

javaVersion=1.8 vs javaVersion=8

From start.spring.io

Request URL: https://start.spring.io/starter.zip?type=maven-project&language=java&bootVersion=3.0.0&baseDir=demo&groupId=com.example&artifactId=demo&name=demo&description=Demo%20project%20for%20Spring%20Boot&packageName=com.example.demo&packaging=jar&javaVersion=1.8

From extension:

vscode-spring-initializr/src/handler/GenerateProjectHandler.ts

Lines 83 to 99 in 7f6bc3a

	private get downloadUrl(): string {
	const params: string[] = [
	`type=${this.projectType}`,
	`language=${this.metadata.language}`,
	`javaVersion=${this.metadata.javaVersion}`,
	`groupId=${this.metadata.groupId}`,
	`artifactId=${this.metadata.artifactId}`,
	`name=${this.metadata.artifactId}`,
	`packaging=${this.metadata.packaging}`,
	`bootVersion=${this.metadata.bootVersion}`,
	`dependencies=${this.metadata.dependencies.id}`,
	];
	const targetUrl = new URL(this.metadata.serviceUrl);
	targetUrl.pathname = "/starter.zip";
	targetUrl.search = `?${params.join("&")}`;
	return targetUrl.toString();

targetUrl.toString()
'https://start.spring.io/starter.zip?type=maven-project&language=java&javaVersion=8&groupId=com.example&artifactId=demo&name=demo&packaging=jar&bootVersion=3.0.0&dependencies='

[Eskibear]

when constructing the url, we should use the "id" 1.8 instead of the "name" 8.

[Eskibear]

it will be available in next nightly build. You can switch to pre-release version then.