@@ -14,6 +14,8 @@
         "target": true,
         "out": true // set this to false to include "out" folder in search results
     },
-    "editor.formatOnSave": false,
+    "[java]": {
+        "editor.formatOnSave": false
+    },
     "java.trace.server": "messages"
 }
@@ -0,0 +1,31 @@
+package org.javacs;
+
+import java.lang.reflect.*;
+import java.util.*;
+import java.util.logging.*;
+
+interface ClassSource {
+    Set<String> classes();
+
+    Class<?> load(String className);
+
+    static final Logger LOG = Logger.getLogger("main");
+    static final Set<String> failedToLoad = new HashSet<>();
+
+    default boolean isPublic(String className) {
+        if (failedToLoad.contains(className)) return false;
+        try {
+            var c = load(className);
+            return Modifier.isPublic(c.getModifiers());
+        } catch (Exception e) {
+            LOG.warning(String.format("Failed to load %s: %s", className, e.getMessage()));
+            failedToLoad.add(className);
+            return false;
+        }
+    }
+
+    default boolean isAccessibleFromPackage(String className, String fromPackage) {
+        var packageName = Parser.mostName(className);
+        return packageName.equals(fromPackage) || isPublic(className);
+    }
+}