Spring Boot Language Server does not start under Eclipse

[Fohlen74]

After installing SpringBoot Tools and restarting Eclipse i get this error message in a popup from "Java Virtual Machine Launcher":
Error: Unable to access jarfile C:\Program Files\Eclipse 4.36\..\..\Users\[user12]\.eclipse\org.eclipse.platform_4.36.0_1777188868_win32_win32_x86_64\plugins\org.springframework.tooling.boot.ls_1.63.0.202506052016\servers\spring-boot-language-server\spring-boot-language-server-1.63.0-SNAPSHOT-exec.jar

The JAR-File that is mentioned here does exist so that I'm sure the Installation of STS is correct. Versions of STS until version 4.23 are working properly.
Also the Initialization of "Spring Boot Language Server" stuck at 28% (Progress View)

My Installation:

• Eclipse J2EE 2025-06 (4.36.0), Build id: 20250605-1316 (installed in C:\Program Files\Eclipse 4.36)
• Spring Boot Language Server Feature 4.31.0.202506052016
• Spring Boot Language Server 1.63.0.202506052016
• Spring IDE Boot Microservices Dash 4.31.0.202506052058
• Spring Tools for Eclipse Main Feature: 4.31.0.202506052058 (installed via Eclipse Marketplace)
• no other Plugins are installed
• Windows 11 (I've tested the same installation on two other computers and there I'm getting the errors, too)

In the Error Log from Eclipse there is nothing special.

Testing it from Commandline I'm getting the same error: Unable to access jarfile.
java -jar "C:\Program Files\Eclipse 4.36\..\..\Users\[user12]\.eclipse\org.eclipse.platform_4.36.0_1777188868_win32_win32_x86_64\plugins\org.springframework.tooling.boot.ls_1.63.0.202506052016\servers\spring-boot-language-server\spring-boot-language-server-1.63.0-SNAPSHOT-exec.jar"

Is this a problem of too long paths? Because when I do
c:\java -jar "C:\Users\[user12]\.eclipse\org.eclipse.platform_4.36.0_1777188868_win32_win32_x86_64\plugins\org.springframework.tooling.boot.ls_1.63.0.202506052016\servers\spring-boot-language-server\spring-boot-language-server-1.63.0-SNAPSHOT-exec.jar" 20:22:48.870 [main] INFO o.s.i.v.b.a.BootLanguageServerBootApp - Starting BootLanguageServerBootApp v1.63.0-SNAPSHOT using Java 21.0.7 with PID 28800 (C:\Users\Thorsten\.eclipse\org.eclipse.platform_4.36.0_1777188868_win32_win32_x86_64\plugins\org.springframework.tooling.boot.ls_1.63.0.202506052016\servers\spring-boot-language-server\spring-boot-language-server-1.63.0-SNAPSHOT-exec.jar started by Thorsten in G:\Projekte\Java\KostalSolarPortal) 20:22:48.875 [main] INFO o.s.i.v.b.a.BootLanguageServerBootApp - No active profile set, falling back to 1 default profile: "default" 20:22:49.579 [main] INFO o.s.i.v.boot.app.SpringSymbolIndex - project listener registered 20:22:49.704 [main] INFO o.s.i.v.b.a.BootLanguageServerBootApp - Started BootLanguageServerBootApp in 1.108 seconds (process running for 1.473) 20:22:49.709 [main] INFO o.s.i.v.c.l.LanguageServerRunner - java.home = C:\Program Files\Eclipse Adoptium\jdk-21.0.7.6-hotspot 20:22:49.709 [LanguageServerApp-lifecycle] INFO o.s.i.v.c.l.LanguageServerRunner - Server ready to start after 1476 ms 20:22:49.709 [LanguageServerApp-lifecycle] INFO o.s.i.v.c.l.LanguageServerRunner - Starting LS as client 20:22:49.709 [LanguageServerApp-lifecycle] INFO o.s.i.v.c.l.LanguageServerRunner - Connected to parent using stdio
I can see on the console that "BootLanguageServerBootApp" is starting.

Also starting Eclipse with SpringBoot Tools from C:\Eclipse everything is ok: no Error-Popup and the SpringBoot Language Server is running well.

To Reproduce
Steps to reproduce the behavior:

• Install Eclipse unter C:\Prorgram Files
• then install STS 4 via the Market Place
• restart Eclipse twice and you will have the failure

Sample

• not possible

And i cannot use Eclipse under C:\Eclipse because my company does not allow to start Programs from other places than C:\Program File or C:\Program Files (x86).
The test with C:\Eclipse was only on my private pc.

[BoykoAlex]

Hmm... I usually have STS on my windows machine buried under folders and it works fine... maybe it is the spaces in the path segments or ..?

[martinlippert]

@BoykoAlex I wonder how to the path is created and whether we can normalize it before passing it along to launch the language server?

[BoykoAlex]

I have pushed in the path normalization to try: a61edc0

STS 4.x snapshots: https://cdn.spring.io/spring-tools/snapshot/STS4/nightly-distributions.html
STS 5.x snapshots: https://cdn.spring.io/spring-tools/snapshot/nightly-distributions.html

[martinlippert]

@Fohlen74 Can you give the latest 4.x snapshots a try to see if this solves the issue?

[Fohlen74]

Yes, it works!!!

My Installation now:

• Eclipse J2EE 2025-06 (4.36.0), Build id: 20250605-1316 (installed in C:\Program Files\Eclipse 4.36)
• Spring Boot Language Server Feature 4.32.0.202508050136
• Spring Boot Language Server 1.64.0.202508050136
• Spring IDE Boot Microservices Dash 4.32.0.202508050142
• Spring Tools for Eclipse Main Feature: 4.32.0.202508050142

And only to confirm I did it right, here is the installation source: https://cdn.spring.io/spring-tools/snapshot/TOOLS/sts4/nightly/e4.36

And with "Logging To Console" switched on, I can see these lines:
20:21:37.846 [main] INFO o.s.i.v.b.a.BootLanguageServerBootApp - Starting BootLanguageServerBootApp v1.64.0-SNAPSHOT using Java 21.0.7 with PID 33040 (C:\Users\user1234\.eclipse\org.eclipse.platform_4.36.0_1777188868_win32_win32_x86_64\plugins\org.springframework.tooling.boot.ls_1.64.0.202508050136\servers\spring-boot-language-server\spring-boot-language-server-1.64.0-SNAPSHOT-exec.jar started by xxxxxxxx in C:\Program Files\Eclipse 4.36) 20:21:37.847 [main] INFO o.s.i.v.b.a.BootLanguageServerBootApp - No active profile set, falling back to 1 default profile: "default" 20:21:38.435 [main] INFO o.s.i.v.boot.app.SpringSymbolIndex - project listener registered 20:21:38.569 [main] INFO o.s.i.v.b.a.BootLanguageServerBootApp - Started BootLanguageServerBootApp in 0.962 seconds (process running for 1.294) 20:21:38.571 [main] INFO o.s.i.v.c.l.LanguageServerRunner - java.home = C:\Program Files\Eclipse 4.36\plugins\org.eclipse.justj.openjdk.hotspot.jre.full.win32.x86_64_21.0.7.v20250502-0916\jre .....

Thank you for the quick reply.

[BoykoAlex]

Nice, thanks for checking! @martinlippert was right then :-)