diff --git a/src/main/java/com/google/api/generator/engine/ast/ConcreteReference.java b/src/main/java/com/google/api/generator/engine/ast/ConcreteReference.java
index c95823fc13..7d37a02417 100644
--- a/src/main/java/com/google/api/generator/engine/ast/ConcreteReference.java
+++ b/src/main/java/com/google/api/generator/engine/ast/ConcreteReference.java
@@ -84,6 +84,9 @@ public String pakkage() {
     return clazz().getPackage().getName();
   }
 
+  @Override
+  public abstract boolean useFullName();
+
   @Override
   public String enclosingClassName() {
     if (!hasEnclosingClass()) {
@@ -129,9 +132,22 @@ public boolean isSupertypeOrEquals(Reference other) {
 
   @Override
   public boolean isAssignableFrom(Reference other) {
+    if (other instanceof VaporReference && ((VaporReference) other).supertypeReference() != null) {
+      return isAssignableFrom(((VaporReference) other).supertypeReference());
+    }
+
     if (!(other instanceof ConcreteReference)) {
       return false;
     }
+
+    if (generics().size() == other.generics().size()) {
+      for (int i = 0; i < generics().size(); i++) {
+        if (!generics().get(i).isSupertypeOrEquals(other.generics().get(i))) {
+          return false;
+        }
+      }
+    }
+
     return clazz().isAssignableFrom(((ConcreteReference) other).clazz());
   }
 
@@ -178,6 +194,7 @@ public static ConcreteReference wildcardWithUpperBound(Reference upperBoundRefer
 
   public static Builder builder() {
     return new AutoValue_ConcreteReference.Builder()
+        .setUseFullName(false)
         .setGenerics(ImmutableList.of())
         .setIsStaticImport(false);
   }
@@ -189,6 +206,8 @@ public static Builder builder() {
   public abstract static class Builder {
     public abstract Builder setClazz(Class clazz);
 
+    public abstract Builder setUseFullName(boolean useFullName);
+
     public abstract Builder setWildcardUpperBound(Reference reference);
 
     public abstract Builder setGenerics(List<Reference> clazzes);
diff --git a/src/main/java/com/google/api/generator/engine/ast/Reference.java b/src/main/java/com/google/api/generator/engine/ast/Reference.java
index 6fd856c78f..ed26731f0f 100644
--- a/src/main/java/com/google/api/generator/engine/ast/Reference.java
+++ b/src/main/java/com/google/api/generator/engine/ast/Reference.java
@@ -27,6 +27,8 @@ public interface Reference {
 
   String pakkage();
 
+  boolean useFullName();
+
   @Nullable
   String enclosingClassName();
 
diff --git a/src/main/java/com/google/api/generator/engine/ast/VaporReference.java b/src/main/java/com/google/api/generator/engine/ast/VaporReference.java
index 4ba17aa356..fbd75afc2e 100644
--- a/src/main/java/com/google/api/generator/engine/ast/VaporReference.java
+++ b/src/main/java/com/google/api/generator/engine/ast/VaporReference.java
@@ -37,10 +37,16 @@ public abstract class VaporReference implements Reference {
   @Override
   public abstract String pakkage();
 
+  @Override
+  public abstract boolean useFullName();
+
   @Nullable
   @Override
   public abstract String enclosingClassName();
 
+  @Nullable
+  public abstract Reference supertypeReference();
+
   @Nullable
   @Override
   public Reference wildcardUpperBound() {
@@ -77,7 +83,7 @@ public boolean isSupertypeOrEquals(Reference other) {
 
   @Override
   public boolean isAssignableFrom(Reference other) {
-    // Not handling this for VaporReference.
+    // Not handling this yet for VaporReference.
     return false;
   }
 
@@ -117,6 +123,7 @@ public Reference copyAndSetGenerics(List<Reference> generics) {
 
   public static Builder builder() {
     return new AutoValue_VaporReference.Builder()
+        .setUseFullName(false)
         .setGenerics(ImmutableList.of())
         .setIsStaticImport(false);
   }
@@ -130,12 +137,16 @@ public abstract static class Builder {
 
     public abstract Builder setPakkage(String pakkage);
 
+    public abstract Builder setUseFullName(boolean useFullName);
+
     public abstract Builder setGenerics(List<Reference> clazzes);
 
     public abstract Builder setEnclosingClassName(String enclosingClassName);
 
     public abstract Builder setIsStaticImport(boolean isStaticImport);
 
+    public abstract Builder setSupertypeReference(Reference supertypeReference);
+
     // Private.
     abstract Builder setPlainName(String plainName);
 
diff --git a/src/main/java/com/google/api/generator/engine/writer/ImportWriterVisitor.java b/src/main/java/com/google/api/generator/engine/writer/ImportWriterVisitor.java
index 94af63747e..fa2648a545 100644
--- a/src/main/java/com/google/api/generator/engine/writer/ImportWriterVisitor.java
+++ b/src/main/java/com/google/api/generator/engine/writer/ImportWriterVisitor.java
@@ -109,7 +109,9 @@ public void visit(TypeNode type) {
     }
 
     List<Reference> refs = new ArrayList<>(type.reference().generics());
-    refs.add(type.reference());
+    if (!type.reference().useFullName()) {
+      refs.add(type.reference());
+    }
     references(refs);
   }
 
@@ -384,6 +386,9 @@ private void variableExpressions(List<VariableExpr> expressions) {
   private void references(List<Reference> refs) {
     for (Reference ref : refs) {
       // Don't need to import this.
+      if (ref.useFullName()) {
+        continue;
+      }
       if (!ref.isStaticImport()
           && (ref.isFromPackage(PKG_JAVA_LANG) || ref.isFromPackage(currentPackage))) {
         continue;
diff --git a/src/main/java/com/google/api/generator/engine/writer/JavaWriterVisitor.java b/src/main/java/com/google/api/generator/engine/writer/JavaWriterVisitor.java
index 6112275b3c..7a1e4d3b6d 100644
--- a/src/main/java/com/google/api/generator/engine/writer/JavaWriterVisitor.java
+++ b/src/main/java/com/google/api/generator/engine/writer/JavaWriterVisitor.java
@@ -145,6 +145,10 @@ public void visit(TypeNode type) {
     if (type.isPrimitiveType()) {
       generatedCodeBuilder.append(typeKind.toString().toLowerCase());
     } else {
+      if (type.reference().useFullName()) {
+        generatedCodeBuilder.append(type.reference().pakkage());
+        generatedCodeBuilder.append(DOT);
+      }
       // A null pointer exception will be thrown if reference is null, which is WAI.
       generatedCodeBuilder.append(type.reference().name());
     }
diff --git a/src/test/java/com/google/api/generator/engine/ast/ConcreteReferenceTest.java b/src/test/java/com/google/api/generator/engine/ast/ConcreteReferenceTest.java
index b284b1bb3a..7083cc280b 100644
--- a/src/test/java/com/google/api/generator/engine/ast/ConcreteReferenceTest.java
+++ b/src/test/java/com/google/api/generator/engine/ast/ConcreteReferenceTest.java
@@ -148,4 +148,89 @@ public void wildcards() {
         "? extends String",
         ConcreteReference.wildcardWithUpperBound(TypeNode.STRING.reference()).name());
   }
+
+  @Test
+  public void isAssignableFrom_concreteRef() {
+    assertFalse(
+        ConcreteReference.withClazz(List.class)
+            .isAssignableFrom(ConcreteReference.withClazz(Map.class)));
+
+    assertTrue(
+        ConcreteReference.withClazz(List.class)
+            .isAssignableFrom(ConcreteReference.withClazz(ArrayList.class)));
+    assertFalse(
+        ConcreteReference.withClazz(ArrayList.class)
+            .isAssignableFrom(ConcreteReference.withClazz(List.class)));
+    assertTrue(
+        ConcreteReference.withClazz(ArrayList.class)
+            .isAssignableFrom(ConcreteReference.withClazz(ArrayList.class)));
+
+    assertTrue(
+        ConcreteReference.withClazz(List.class)
+            .isAssignableFrom(
+                ConcreteReference.builder()
+                    .setClazz(ArrayList.class)
+                    .setGenerics(Arrays.asList(ConcreteReference.withClazz(String.class)))
+                    .build()));
+    assertTrue(
+        ConcreteReference.builder()
+            .setClazz(List.class)
+            .setGenerics(Arrays.asList(ConcreteReference.withClazz(String.class)))
+            .build()
+            .isAssignableFrom(
+                ConcreteReference.builder()
+                    .setClazz(ArrayList.class)
+                    .setGenerics(Arrays.asList(ConcreteReference.withClazz(String.class)))
+                    .build()));
+    assertFalse(
+        ConcreteReference.builder()
+            .setClazz(List.class)
+            .setGenerics(Arrays.asList(ConcreteReference.withClazz(Integer.class)))
+            .build()
+            .isAssignableFrom(
+                ConcreteReference.builder()
+                    .setClazz(ArrayList.class)
+                    .setGenerics(Arrays.asList(ConcreteReference.withClazz(String.class)))
+                    .build()));
+  }
+
+  @Test
+  public void isAssignableFrom_vaporRef() {
+    assertFalse(
+        ConcreteReference.withClazz(List.class)
+            .isAssignableFrom(
+                VaporReference.builder().setName("ArrayList").setPakkage("java.util").build()));
+    assertFalse(
+        ConcreteReference.withClazz(ArrayList.class)
+            .isAssignableFrom(
+                VaporReference.builder().setName("ArrayList").setPakkage("java.util").build()));
+  }
+
+  @Test
+  public void isAssignableFrom_vaporRefWithConcreteRefSupertype() {
+    assertTrue(
+        ConcreteReference.withClazz(List.class)
+            .isAssignableFrom(
+                VaporReference.builder()
+                    .setName("ArrayList")
+                    .setPakkage("java.util")
+                    .setSupertypeReference(ConcreteReference.withClazz(List.class))
+                    .build()));
+    assertTrue(
+        ConcreteReference.withClazz(List.class)
+            .isAssignableFrom(
+                VaporReference.builder()
+                    .setName("SpecialArrayList")
+                    .setPakkage("com.foo.bar")
+                    .setSupertypeReference(ConcreteReference.withClazz(ArrayList.class))
+                    .build()));
+    assertFalse(
+        ConcreteReference.withClazz(List.class)
+            .isAssignableFrom(
+                VaporReference.builder()
+                    .setName("HashMap")
+                    .setPakkage("java.util")
+                    .setSupertypeReference(ConcreteReference.withClazz(Map.class))
+                    .build()));
+  }
 }
diff --git a/src/test/java/com/google/api/generator/engine/writer/ImportWriterVisitorTest.java b/src/test/java/com/google/api/generator/engine/writer/ImportWriterVisitorTest.java
index 352b52379e..5a936b61b3 100644
--- a/src/test/java/com/google/api/generator/engine/writer/ImportWriterVisitorTest.java
+++ b/src/test/java/com/google/api/generator/engine/writer/ImportWriterVisitorTest.java
@@ -76,6 +76,36 @@ public void setUp() {
     writerVisitor.initialize(CURRENT_PACKAGE, CURRENT_CLASS);
   }
 
+  @Test
+  public void writeReferenceTypeImports_basic() {
+    TypeNode.withReference(ConcreteReference.withClazz(List.class)).accept(writerVisitor);
+    assertEquals("import java.util.List;\n\n", writerVisitor.write());
+
+    writerVisitor.clear();
+    TypeNode.withReference(
+            VaporReference.builder().setName("FooBar").setPakkage("com.foo.bar").build())
+        .accept(writerVisitor);
+    assertEquals("import com.foo.bar.FooBar;\n\n", writerVisitor.write());
+  }
+
+  @Test
+  public void writeReferenceTypeImports_useFullName() {
+    TypeNode.withReference(
+            ConcreteReference.builder().setClazz(List.class).setUseFullName(true).build())
+        .accept(writerVisitor);
+    assertEquals("", writerVisitor.write());
+
+    writerVisitor.clear();
+    TypeNode.withReference(
+            VaporReference.builder()
+                .setName("FooBar")
+                .setPakkage("com.foo.bar")
+                .setUseFullName(true)
+                .build())
+        .accept(writerVisitor);
+    assertEquals("", writerVisitor.write());
+  }
+
   @Test
   public void writeNewObjectExprImports_basic() {
     // [Constructing] `new ArrayList<>()`
diff --git a/src/test/java/com/google/api/generator/engine/writer/JavaWriterVisitorTest.java b/src/test/java/com/google/api/generator/engine/writer/JavaWriterVisitorTest.java
index 5745b8e01f..bfa090c228 100644
--- a/src/test/java/com/google/api/generator/engine/writer/JavaWriterVisitorTest.java
+++ b/src/test/java/com/google/api/generator/engine/writer/JavaWriterVisitorTest.java
@@ -107,6 +107,36 @@ public void writePrimitiveArrayType() {
     assertEquals(writerVisitor.write(), "byte[]");
   }
 
+  @Test
+  public void writeReferenceType_basic() {
+    TypeNode.withReference(ConcreteReference.withClazz(List.class)).accept(writerVisitor);
+    assertEquals("List", writerVisitor.write());
+
+    writerVisitor.clear();
+    TypeNode.withReference(
+            VaporReference.builder().setName("FooBar").setPakkage("com.foo.bar").build())
+        .accept(writerVisitor);
+    assertEquals("FooBar", writerVisitor.write());
+  }
+
+  @Test
+  public void writeReferenceType_useFullName() {
+    TypeNode.withReference(
+            ConcreteReference.builder().setClazz(List.class).setUseFullName(true).build())
+        .accept(writerVisitor);
+    assertEquals("java.util.List", writerVisitor.write());
+
+    writerVisitor.clear();
+    TypeNode.withReference(
+            VaporReference.builder()
+                .setName("FooBar")
+                .setPakkage("com.foo.bar")
+                .setUseFullName(true)
+                .build())
+        .accept(writerVisitor);
+    assertEquals("com.foo.bar.FooBar", writerVisitor.write());
+  }
+
   @Test
   public void writeAnnotation_simple() {
     AnnotationNode annotation = AnnotationNode.OVERRIDE;