1 files changed, 13 insertions, 0 deletions
diff --git a/src/main/java/org/javacs/SourceFileManager.java b/src/main/java/org/javacs/SourceFileManager.java
index b7e701e..dfef972 100644
--- a/src/main/java/org/javacs/SourceFileManager.java
+++ b/src/main/java/org/javacs/SourceFileManager.java
@@ -22,17 +22,30 @@ class SourceFileManager extends ForwardingJavaFileManager<StandardJavaFileManage
         LOG.warning(error.getMessage(null));
     }
 
+    private final LruCache<String, Iterable<JavaFileObject>> cacheClassPath = new LruCache<>(1000, this::listClassPath);
+
     @Override
     public Iterable<JavaFileObject> list(
             Location location, String packageName, Set<JavaFileObject.Kind> kinds, boolean recurse) throws IOException {
         if (location == StandardLocation.SOURCE_PATH) {
             var stream = FileStore.list(packageName).stream().map(this::asJavaFileObject);
             return stream::iterator;
+        } else if (location == StandardLocation.CLASS_PATH) {
+            // Listing large class paths is expensive
+            return cacheClassPath.get(packageName);
         } else {
             return super.list(location, packageName, kinds, recurse);
         }
     }
 
+    private Iterable<JavaFileObject> listClassPath(String packageName) {
+        try {
+            return super.list(StandardLocation.CLASS_PATH, packageName, Set.of(JavaFileObject.Kind.values()), false);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     private JavaFileObject asJavaFileObject(Path file) {
         return new SourceFileObject(file);
     }