Need help configuring jdtls #77

Sturm0 · 2025-06-06T22:57:30Z

Sturm0
Jun 6, 2025

Hello,

I don't know how to configure jdtls in Geany.

I have jdtls installed:

Sturm0@Sturm0-PC-ESCRITORIO:~/.config/geany/plugins/lsp$ jdtls --version
jdtls-launcher v1.2.0
equinox-launcher 1.7.0.v20250519-0528
jdtls-core 1.48.0.202506032041
lombok custom
openjdk 21.0.7 2025-04-15
OpenJDK Runtime Environment (build 21.0.7+6-Ubuntu-0ubuntu124.04)
OpenJDK 64-Bit Server VM (build 21.0.7+6-Ubuntu-0ubuntu124.04, mixed mode, sharing)

In lsp.conf I have the following:

[Java]
cmd=jdtls
autocomplete_use_label=false
initialization_options_file=/home/Sturm0/.config/jdtls_init_options.json
#semantic_tokens_enable=true
#rpc_log=stdout
#rpc_log_full=true
#show_server_stderr=true

I tried writing the initialization request using this: https://github.com/eclipse-jdtls/eclipse.jdt.ls/wiki/Running-the-JAVA-LS-server-from-the-command-line#initialize-request

In jdtls_init_options.json i have:

{
    "initializationOptions": {
        "bundles": [
        ],
        "workspaceFolders": [
            "file:///home/Sturm0/Documentos/TP-2-Algoritmos-Algonautas"
        ],
        "settings": {
            "java": {
                "home": "/usr/lib/jvm/java-21-openjdk-amd64",
                "errors": {
                    "incompleteClasspath": {
                        "severity": "warning"
                    }
                },
                "configuration": {
                    "updateBuildConfiguration": "interactive",
                    "maven": {
                        "userSettings": null
                    }
                },
                "trace": {
                    "server": "verbose"
                },
                "import": {
                    "gradle": {
                        "enabled": true
                    },
                    "maven": {
                        "enabled": true
                    },
                    "exclusions": [
                        "**/node_modules/**",
                        "**/.metadata/**",
                        "**/archetype-resources/**",
                        "**/META-INF/maven/**",
                        "/**/test/**"
                    ]
                },
                "referencesCodeLens": {
                    "enabled": false
                },
                "signatureHelp": {
                    "enabled": false
                },
                "implementationsCodeLens": {
                    "enabled": false
                },
                "format": {
                    "enabled": true
                },
                "saveActions": {
                    "organizeImports": false
                },
                "contentProvider": {
                    "preferred": null
                },
                "autobuild": {
                    "enabled": false
                },
                "completion": {
                    "favoriteStaticMembers": [
                        "org.junit.Assert.*",
                        "org.junit.Assume.*",
                        "org.junit.jupiter.api.Assertions.*",
                        "org.junit.jupiter.api.Assumptions.*",
                        "org.junit.jupiter.api.DynamicContainer.*",
                        "org.junit.jupiter.api.DynamicTest.*"
                    ],
                    "importOrder": [
                        "java",
                        "javax",
                        "com",
                        "org"
                    ]
                }
            }
        }
    }
}

But when I open Geany with a project with Java code I get the following:

00:47:16: Starting LSP server vscode-json-languageserver --stdio
00:47:16: LSP server process vscode-json-languageserver --stdio failed to start, giving up: No existe el archivo o el directorio
00:48:35: Starting LSP server jdtls
00:48:35: Sending initialize request to LSP server jdtls
00:48:36: Initialize request failed for LSP server jdtls: Invalid or missing Content-Length header from peer
00:48:36: Force terminating jdtls

I don't really know what's the vscode thing in 00:47:16. I installed jdtls using this btw

I also don't know how to set WorkspaceFolders to use the current project's base path. Or what I should put there so I don't have to reconfigure it for each project.

Answered by techee

Jun 8, 2025

00:48:36: Initialize request failed for LSP server jdtls: Invalid or missing Content-Length header from peer

This means that the server didn't respond with a valid JSON-RPC message.

Where do you have the jdtls server from? I've tested it with https://download.eclipse.org/jdtls/milestones/1.43.0/ which seems to work (I'm on an ARM64 Debian 12 and it's a problem to get Java 21 for it and 1.43 is the last release requiring Java 17).

My version of jdtls doesn't seem to have the --version command-line argument (but it's possible it was added in later versions). So it's quite possible that some extra command-line argument is required to run jdtls in the server mode. What happens when you run j…

View full answer

techee · 2025-06-08T13:56:16Z

techee
Jun 8, 2025
Maintainer

00:48:36: Initialize request failed for LSP server jdtls: Invalid or missing Content-Length header from peer

This means that the server didn't respond with a valid JSON-RPC message.

Where do you have the jdtls server from? I've tested it with https://download.eclipse.org/jdtls/milestones/1.43.0/ which seems to work (I'm on an ARM64 Debian 12 and it's a problem to get Java 21 for it and 1.43 is the last release requiring Java 17).

My version of jdtls doesn't seem to have the --version command-line argument (but it's possible it was added in later versions). So it's quite possible that some extra command-line argument is required to run jdtls in the server mode. What happens when you run jdtls from the command line? In principle, the command should block until you press Ctrl+C to terminate it. If not, try to figure out what command-line option may be missing and add it to the cmd configuration option.

I think the initialization options file should be optional (but if you need it, I think you should remove the top-most "initializationOptions" dict which I think shouldn't be there).

00:47:16: Starting LSP server vscode-json-languageserver --stdio
00:47:16: LSP server process vscode-json-languageserver --stdio failed to start, giving up: No existe el archivo o el directorio

You probably have some json file open and it tries to launch the json server for it. You can set cmd= (without any value) in the config file under the JSON section to silence it. It shouldn't be related to the jdtls server problem in any way though.

5 replies

Sturm0 Jun 9, 2025
Author

Using https://download.eclipse.org/jdtls/milestones/1.43.0/ and without the initialization file is working, thanks !!

techee Jun 9, 2025
Maintainer

Thanks. Still, it would be good to know what's going on with the 1.48 version you were using. It's possible you did run into the same problem like me that you didn't have Java 21 on your system. What does jdtls 1.48 say when you run it from the command-line?

Sturm0 Jun 11, 2025
Author

Sturm0@Sturm0-PC-ESCRITORIO:~$ jdtls
jun 10, 2025 11:34:50 P. M. org.apache.aries.spifly.BaseActivator log
INFORMACIÓN: Registered provider ch.qos.logback.classic.spi.LogbackServiceProvider of service org.slf4j.spi.SLF4JServiceProvider in bundle ch.qos.logback.classic
23:34:51,946 |-INFO in ch.qos.logback.classic.LoggerContext[default] - This is logback-classic version 1.5.17
23:34:51,947 |-INFO in ch.qos.logback.classic.LoggerContext[default] - This is logback-core version 1.5.18
23:34:51,947 |-WARN in ch.qos.logback.classic.LoggerContext[default] - Versions of logback-core and logback-classic are different!
23:34:51,957 |-INFO in ch.qos.logback.classic.util.ContextInitializer@6c20691f - Here is a list of configurators discovered as a service, by rank: 
23:34:51,957 |-INFO in ch.qos.logback.classic.util.ContextInitializer@6c20691f -   org.eclipse.jdt.ls.logback.appender.JavaLsConfigurator
23:34:51,957 |-INFO in ch.qos.logback.classic.util.ContextInitializer@6c20691f - They will be invoked in order until ExecutionStatus.DO_NOT_INVOKE_NEXT_IF_ANY is returned.
23:34:51,958 |-INFO in ch.qos.logback.classic.util.ContextInitializer@6c20691f - Constructed configurator of type class org.eclipse.jdt.ls.logback.appender.JavaLsConfigurator
23:34:51,958 |-INFO in org.eclipse.jdt.ls.logback.appender.JavaLsConfigurator@5c64526e - Setting up default configuration.
23:34:51,962 |-INFO in ch.qos.logback.classic.util.ContextInitializer@6c20691f - org.eclipse.jdt.ls.logback.appender.JavaLsConfigurator.configure() call lasted 2 milliseconds. ExecutionStatus=DO_NOT_INVOKE_NEXT_IF_ANY

Content-Length: 174

{"jsonrpc":"2.0","method":"window/logMessage","params":{"type":3,"message":"10 jun 2025 23:34:53 class org.eclipse.jdt.ls.core.internal.JavaLanguageServerPlugin is started"}}Content-Length: 139

{"jsonrpc":"2.0","method":"window/logMessage","params":{"type":3,"message":"10 jun 2025 23:34:53 Started org.eclipse.buildship.core 74ms"}}Content-Length: 132

{"jsonrpc":"2.0","method":"window/logMessage","params":{"type":3,"message":"10 jun 2025 23:34:53 Started org.eclipse.m2e.core 0ms"}}Content-Length: 138

{"jsonrpc":"2.0","method":"window/logMessage","params":{"type":3,"message":"10 jun 2025 23:34:53 ProjectRegistryRefreshJob finished 2ms"}}Content-Length: 122

{"jsonrpc":"2.0","method":"window/logMessage","params":{"type":3,"message":"10 jun 2025 23:34:53 Main thread is waiting"}}

I have some jdk 21 stuff: ```

Sturm0@Sturm0-PC-ESCRITORIO:~$ dpkg --get-selections | grep jdk
default-jdk install
default-jdk-headless install
openjdk-21-jdk:amd64 install
openjdk-21-jdk-headless:amd64 install
openjdk-21-jre:amd64 install
openjdk-21-jre-headless:amd64 install
openjdk-8-jre:amd64 install
openjdk-8-jre-headless:amd64 install

techee Jun 11, 2025
Maintainer

Alright, I think this is something I'll have to test myself (once I install linux on something where I'll be able to reproduce it).

techee Jun 16, 2025
Maintainer

See eclipse-jdtls/eclipse.jdt.ls#3469.

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