ZIm/docs/src/languages/java.md

Java

There are two extensions that provide Java language support for Zed:

• Zed Java: zed-extensions/java and
• Java with Eclipse JDTLS: zed-java-eclipse-jdtls.

Both use:

• Tree Sitter: tree-sitter/tree-sitter-java
• Language Server: eclipse-jdtls/eclipse.jdt.ls

Pre-requisites

Install OpenJDK

You will need to install a Java runtime (OpenJDK).

• MacOS: brew install openjdk
• Ubuntu: sudo add-apt-repository ppa:openjdk-23 && sudo apt-get install openjdk-23
• Windows: choco install openjdk
• Arch Linux: sudo pacman -S jre-openjdk-headless

Or manually download and install OpenJDK 23.

(Optional) Install JDTLS

If you are using Java with Eclipse JDTLS, you can skip this section as it will automatically download a binary for you.

If you are using Zed Java you need to install your own copy of Eclipse JDT Language Server (eclipse.jdt.ls).

• MacOS: brew install jdtls
• Arch: jdtls from AUR

Or manually download install:

• JDTLS Milestone Builds (updated every two weeks)
• JDTLS Snapshot Builds (frequent updates)

Extension Install

You can install either by opening {#action zed::Extensions}({#kb zed::Extensions}) and searching for java. We recommend you install one or the other and not both.

Settings / Initialization Options

For available initialization_options please see the Initialize Request section of the Eclipse.jdt.ls Wiki.

Add the following to your Zed Settings by launching {#action zed::OpenSettings}({#kb zed::OpenSettings}).

Zed Java Settings

{
  "lsp": {
    "jdtls": {
      "settings": {},
      "initialization_options": {}
    }
  }
}

Java with Eclipse JDTLS settings

{
  "lsp": {
    "java": {
      "settings": {},
      "initialization_options": {}
    }
  }
}

See also

• Zed Java Readme
• Java with Eclipse JDTLS Readme

Support

If you have issues with either of these plugins, please open issues on their respective repositories:

• Zed Java Issues
• Java with Eclipse JDTLS Issues

Example Configs

Zed Java Classpath

You can optionally configure the class path that JDTLS uses with:

{
  "lsp": {
    "jdtls": {
      "settings": {
        "classpath": "/path/to/classes.jar:/path/to/more/classes/"
      }
    }
  }
}

Zed Java Initialization Options

There are also many more options you can pass directly to the language server, for example:

{
  "lsp": {
    "jdtls": {
      "initialization_options": {
        "bundles": [],
        "workspaceFolders": ["file:///home/snjeza/Project"],
        "settings": {
          "java": {
            "home": "/usr/local/jdk-9.0.1",
            "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"]
            }
          }
        }
      }
    }
  }
}

Java with Eclipse JTDLS Configuration

Configuration options match those provided in the redhat-developer/vscode-java extension.

For example, to enable Lombok Support:

{
  "lsp": {
    "java": {
      "settings": {
        "java.jdt.ls.lombokSupport.enabled:": true
      }
    }
  }
}