WIP: enable javac-based compilation

Signed-off-by: Fred Bricon <[email protected]>

Author: fbricon

package.json

@@ -404,6 +404,17 @@
             "scope": "window",
             "order": 90
           },
+          "java.jdt.ls.javac.enabled": {
+            "type": "string",
+            "enum": [
+              "on",
+              "off"
+            ],
+            "default": "off",
+            "markdownDescription": "[Experimental] Specify whether to enable Javac-based compilation in the language server. Requires running this extension with Java 22",
+            "scope": "window",
+            "order": 95
+          },
           "java.trace.server": {
             "type": "string",
             "enum": [
@@ -1903,4 +1914,4 @@
   },
   "segmentWriteKey": "Y7Y5Xk8dKEhVZHTmAkFZkqgdN4d7c4lt",
   "segmentWriteKeyDebug": "BflPll7uuKOCm3y0g7JpfXLVBVFBivDE"
-}
+}

src/javaServerStarter.ts

@@ -106,7 +106,36 @@ function prepareParams(requirements: RequirementsData, workspacePath, context: E
 				// See https://github.com/redhat-developer/vscode-java/issues/2264
 				// It requires the internal API sun.nio.fs.WindowsFileAttributes.isDirectoryLink() to check if a Windows directory is symlink.
 				'--add-opens',
-				'java.base/sun.nio.fs=ALL-UNNAMED');
+				'java.base/sun.nio.fs=ALL-UNNAMED'
+				);
+
+	const javacEnabled = 'on' === getJavaConfiguration().get('jdt.ls.javac.enabled');
+	if (javacEnabled) {
+		// Javac flags
+		params.push(
+		'--add-opens',
+		'jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED',
+		'--add-opens',
+		'jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED',
+		'--add-opens',
+		'jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED',
+		'--add-opens',
+		'jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED',
+		'--add-opens',
+		'jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED',
+		'--add-opens',
+		'jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED',
+		'--add-opens',
+		'jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED',
+		'--add-opens',
+		'jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED',
+		'-DICompilationUnitResolver=org.eclipse.jdt.core.dom.JavacCompilationUnitResolver',
+		'-DCompilationUnit.DOM_BASED_OPERATIONS=true',
+		// Javac based completion is useless for now
+		// '-DCompilationUnit.codeComplete.DOM_BASED_OPERATIONS=true',
+		'-DAbstractImageBuilder.compiler=org.eclipse.jdt.internal.javac.JavacCompiler'
+		);
+	}
 
 	params.push('-Declipse.application=org.eclipse.jdt.ls.core.id1',
 				'-Dosgi.bundles.defaultStartLevel=4',

src/requirements.ts

@@ -10,7 +10,7 @@ import { logger } from './log';
 import { checkJavaPreferences } from './settings';
 import { listJdks, sortJdksBySource, sortJdksByVersion } from './jdkUtils';
 
-const REQUIRED_JDK_VERSION = 17;
+const REQUIRED_JDK_VERSION = 22;
 /* eslint-disable @typescript-eslint/naming-convention */
 export interface RequirementsData {
     tooling_jre: string;

src/settings.ts

@@ -136,7 +136,8 @@ function hasJavaConfigChanged(oldConfig: WorkspaceConfiguration, newConfig: Work
 		|| hasConfigKeyChanged('jdt.ls.vmargs', oldConfig, newConfig)
 		|| hasConfigKeyChanged('server.launchMode', oldConfig, newConfig)
 		|| hasConfigKeyChanged('sharedIndexes.location', oldConfig, newConfig)
-		|| hasConfigKeyChanged('transport', oldConfig, newConfig);
+		|| hasConfigKeyChanged('transport', oldConfig, newConfig)
+		|| hasConfigKeyChanged('jdt.ls.javac.enabled', oldConfig, newConfig);
 }
 
 function hasConfigKeyChanged(key, oldConfig, newConfig) {