use breadth-first dependency collector impl

Signed-off-by: Yan Zhang <yanzh@microsoft.com>

src/javaServerStarter.ts

@@ -19,12 +19,20 @@ const DEBUG = (typeof v8debug === 'object') || startedInDebugMode();
 /**
  * Argument that tells the program where to generate the heap dump that is created when an OutOfMemoryError is raised and `HEAP_DUMP` has been passed
  */
- export const HEAP_DUMP_LOCATION = '-XX:HeapDumpPath=';
+export const HEAP_DUMP_LOCATION = '-XX:HeapDumpPath=';
 
- /**
-  * Argument that tells the program to generate a heap dump file when an OutOfMemoryError is raised
-  */
- export const HEAP_DUMP = '-XX:+HeapDumpOnOutOfMemoryError';
+/**
+ * Argument that tells the program to generate a heap dump file when an OutOfMemoryError is raised
+ */
+export const HEAP_DUMP = '-XX:+HeapDumpOnOutOfMemoryError';
+
+/**
+ * Argument that specifies name of the dependency collector implementation to use.
+ * `df` for depth-first and `bf` for breadth-first.
+ * See: https://github.com/apache/maven-resolver/blob/maven-resolver-1.9.7/src/site/markdown/configuration.md
+ */
+const DEPENDENCY_COLLECTOR_IMPL= '-Daether.dependencyCollector.impl=';
+const DEPENDENCY_COLLECTOR_IMPL_BF= 'bf';
 
 export function prepareExecutable(requirements: RequirementsData, workspacePath, javaConfig, context: ExtensionContext, isSyntaxServer: boolean): Executable {
 	const executable: Executable = Object.create(null);
@@ -130,6 +138,9 @@ function prepareParams(requirements: RequirementsData, javaConfiguration, worksp
 		if (vmargs.indexOf(HEAP_DUMP_LOCATION) < 0) {
 			params.push(`${HEAP_DUMP_LOCATION}${path.dirname(workspacePath)}`);
 		}
+		if (vmargs.indexOf(DEPENDENCY_COLLECTOR_IMPL) < 0) {
+			params.push(`${DEPENDENCY_COLLECTOR_IMPL}${DEPENDENCY_COLLECTOR_IMPL_BF}`);
+		}
 
 		const sharedIndexLocation: string = resolveIndexCache(context);
 		if (sharedIndexLocation) {