diff --git a/src/bin/dvm/main.rs b/src/bin/dvm/main.rs
index 35a9918..4c995a4 100644
--- a/src/bin/dvm/main.rs
+++ b/src/bin/dvm/main.rs
@@ -70,9 +70,7 @@ fn main() {
     let unsafe_pointer_impl_rc = Rc::new(pointer_impl);
 
     mem_lib.interfaces.push(pointer_int_rc.clone());
-    mem_lib
-        .implementations
-        .push(unsafe_pointer_impl_rc.clone());
+    mem_lib.implementations.push(unsafe_pointer_impl_rc.clone());
 
     // std::unsafe::alloc(
     //   r0: size Long
@@ -169,7 +167,10 @@ fn main() {
 
     // std::core::String
     let mut string_lib = DmLib::new("std/core/string");
-    let mut string_impl = DmImplementation::new("std::core::String", "String", None);
+
+    let string_int = DmInterface::new("std::core::String", "String");
+
+    let mut string_impl = DmImplementation::new("std::core::StringImpl", "StringImpl", None);
 
     let bytes_field = DmField::new("bytes", DmType::Pointer, 0);
 
@@ -186,7 +187,7 @@ fn main() {
     );
 
     let string_ctor_0_fn = DmFn::new(
-        "std::core::String::_ctor_0",
+        "std::core::StringImpl::_ctor_0",
         "_ctor_0",
         string_ctor_0_bytecode,
         2,
@@ -199,6 +200,7 @@ fn main() {
     string_impl.methods.push(Rc::new(string_ctor_0_method));
     let core_string_impl_size = string_impl.size_in_bytes();
 
+    string_lib.interfaces.push(Rc::new(string_int));
     string_lib.implementations.push(Rc::new(string_impl));
 
     // greeting lib
@@ -217,7 +219,7 @@ fn main() {
         &mut main_byte_code,
         0,
         core_string_impl_size as u32,
-        "std::core::String",
+        "std::core::StringImpl",
     );
     add_mov_const(&mut main_byte_code, 1, "greeting", 0);
     add_invoke_fn(
@@ -234,7 +236,12 @@ fn main() {
 
     let mut state = DvmState::new();
     let mut context = DvmContext::new();
-    context.load_functions(&vec![greeting_lib, string_lib, mem_lib]);
+    context.load(vec![
+        Rc::new(greeting_lib), 
+        Rc::new(string_lib), 
+        Rc::new(array_lib), 
+        Rc::new(mem_lib)
+    ]);
 
     let main_fn = context.fn_by_fqn("main").unwrap();
     call_fn(&mut state, &context, &main_fn, vec![]);
diff --git a/src/vm/dvm_value.rs b/src/vm/dvm_value.rs
index 12dda18..3ef7971 100644
--- a/src/vm/dvm_value.rs
+++ b/src/vm/dvm_value.rs
@@ -18,7 +18,7 @@ impl DvmValue {
         if let DvmValue::Long(l) = self {
             *l
         } else {
-            panic!("Expected DvmValue::long, but found {:?}", self)
+            panic!("Expected DvmValue::Long, but found {:?}", self)
         }
     }
 
diff --git a/src/vm/mod.rs b/src/vm/mod.rs
index 87f9ff7..112aea8 100644
--- a/src/vm/mod.rs
+++ b/src/vm/mod.rs
@@ -29,7 +29,7 @@ struct CallFrameInfo {
 }
 
 pub struct DvmContext {
-    libs: Vec<DmLib>,
+    libs: Vec<Rc<DmLib>>,
     functions: HashMap<String, Rc<DmFn>>,
     platform_functions: HashMap<String, Rc<PlatformFunction>>,
 }
@@ -43,8 +43,9 @@ impl DvmContext {
         }
     }
 
-    pub fn load_functions(&mut self, libs: &Vec<DmLib>) {
+    pub fn load(&mut self, libs: Vec<Rc<DmLib>>) {
         for lib in libs {
+            self.libs.push(lib.clone());
             for lib_fn in &lib.functions {
                 self.functions
                     .insert(lib_fn.fqn().to_string(), lib_fn.clone());
@@ -69,6 +70,16 @@ impl DvmContext {
                     implementation_function.clone(),
                 );
             }
+            for method in lib
+                .implementations
+                .iter()
+                .flat_map(|implementation| &implementation.methods)
+            {
+                self.functions.insert(
+                    method.dm_fn().fqn().to_string(),
+                    method.dm_fn().clone(),
+                );
+            }
         }
     }
 
@@ -527,7 +538,7 @@ pub fn run_byte_code(state: &mut DvmState, context: &DvmContext, byte_code: &[u8
                     .expect(&format!("Could not find method: {}", symbol_name));
                 let dm_fn = method.dm_fn();
 
-                let call_result = call_fn(state, context, dm_fn, args);
+                let call_result = call_fn(state, context, &dm_fn, args);
                 state.registers.insert(return_register, call_result);
             }
             INVOKE_DYNAMIC => {
diff --git a/src/vm/object_type.rs b/src/vm/object_type.rs
index 73a42bd..5f209c6 100644
--- a/src/vm/object_type.rs
+++ b/src/vm/object_type.rs
@@ -82,8 +82,8 @@ impl DmMethod {
         }
     }
 
-    pub fn dm_fn(&self) -> &DmFn {
-        &self.dm_fn
+    pub fn dm_fn(&self) -> Rc<DmFn> {
+        self.dm_fn.clone()
     }
 }