Update the codebase now that we require Java 8 (#617)

20 files changed, 68 insertions, 113 deletions

diff --git a/src/main/java/com/squareup/javapoet/AnnotationSpec.java b/src/main/java/com/squareup/javapoet/AnnotationSpec.java
index 0c96756..d1c5e53 100644
--- a/src/main/java/com/squareup/javapoet/AnnotationSpec.java
+++ b/src/main/java/com/squareup/javapoet/AnnotationSpec.java
@@ -34,7 +34,7 @@ import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.element.VariableElement;
 import javax.lang.model.type.TypeMirror;
-import javax.lang.model.util.SimpleAnnotationValueVisitor7;
+import javax.lang.model.util.SimpleAnnotationValueVisitor8;
 
 import static com.squareup.javapoet.Util.characterLiteralWithoutSingleQuotes;
 import static com.squareup.javapoet.Util.checkArgument;
@@ -113,12 +113,7 @@ public final class AnnotationSpec {
     Builder builder = builder(annotation.annotationType());
     try {
       Method[] methods = annotation.annotationType().getDeclaredMethods();
-      Arrays.sort(methods, new Comparator<Method>() {
-        @Override
-        public int compare(Method m1, Method m2) {
-          return m1.getName().compareTo(m2.getName());
-        }
-      });
+      Arrays.sort(methods, Comparator.comparing(Method::getName));
       for (Method method : methods) {
         Object value = method.invoke(annotation);
         if (!includeDefaultValues) {
@@ -210,11 +205,7 @@ public final class AnnotationSpec {
     public Builder addMember(String name, CodeBlock codeBlock) {
       checkNotNull(name, "name == null");
       checkArgument(SourceVersion.isName(name), "not a valid name: %s", name);
-      List<CodeBlock> values = members.get(name);
-      if (values == null) {
-        values = new ArrayList<>();
-        members.put(name, values);
-      }
+      List<CodeBlock> values = members.computeIfAbsent(name, k -> new ArrayList<>());
       values.add(codeBlock);
       return this;
     }
@@ -254,7 +245,7 @@ public final class AnnotationSpec {
   /**
    * Annotation value visitor adding members to the given builder instance.
    */
-  private static class Visitor extends SimpleAnnotationValueVisitor7<Builder, String> {
+  private static class Visitor extends SimpleAnnotationValueVisitor8<Builder, String> {
     final Builder builder;
 
     Visitor(Builder builder) {
diff --git a/src/main/java/com/squareup/javapoet/ArrayTypeName.java b/src/main/java/com/squareup/javapoet/ArrayTypeName.java
index 2d02b33..7c54465 100644
--- a/src/main/java/com/squareup/javapoet/ArrayTypeName.java
+++ b/src/main/java/com/squareup/javapoet/ArrayTypeName.java
@@ -31,7 +31,7 @@ public final class ArrayTypeName extends TypeName {
   public final TypeName componentType;
 
   private ArrayTypeName(TypeName componentType) {
-    this(componentType, new ArrayList<AnnotationSpec>());
+    this(componentType, new ArrayList<>());
   }
 
   private ArrayTypeName(TypeName componentType, List<AnnotationSpec> annotations) {
@@ -63,7 +63,7 @@ public final class ArrayTypeName extends TypeName {
 
   /** Returns an array type equivalent to {@code mirror}. */
   public static ArrayTypeName get(ArrayType mirror) {
-    return get(mirror, new LinkedHashMap<TypeParameterElement, TypeVariableName>());
+    return get(mirror, new LinkedHashMap<>());
   }
 
   static ArrayTypeName get(
@@ -73,7 +73,7 @@ public final class ArrayTypeName extends TypeName {
 
   /** Returns an array type equivalent to {@code type}. */
   public static ArrayTypeName get(GenericArrayType type) {
-    return get(type, new LinkedHashMap<Type, TypeVariableName>());
+    return get(type, new LinkedHashMap<>());
   }
 
   static ArrayTypeName get(GenericArrayType type, Map<Type, TypeVariableName> map) {
diff --git a/src/main/java/com/squareup/javapoet/ClassName.java b/src/main/java/com/squareup/javapoet/ClassName.java
index 4161025..c5c065d 100644
--- a/src/main/java/com/squareup/javapoet/ClassName.java
+++ b/src/main/java/com/squareup/javapoet/ClassName.java
@@ -40,7 +40,7 @@ public final class ClassName extends TypeName implements Comparable<ClassName> {
   final String canonicalName;
 
   private ClassName(List<String> names) {
-    this(names, new ArrayList<AnnotationSpec>());
+    this(names, new ArrayList<>());
   }
 
   private ClassName(List<String> names, List<AnnotationSpec> annotations) {
@@ -50,8 +50,8 @@ public final class ClassName extends TypeName implements Comparable<ClassName> {
     }
     this.names = Util.immutableList(names);
     this.canonicalName = (names.get(0).isEmpty()
-        ? Util.join(".", names.subList(1, names.size()))
-        : Util.join(".", names));
+        ? String.join(".", names.subList(1, names.size()))
+        : String.join(".", names));
   }
 
   @Override public ClassName annotated(List<AnnotationSpec> annotations) {
diff --git a/src/main/java/com/squareup/javapoet/CodeBlock.java b/src/main/java/com/squareup/javapoet/CodeBlock.java
index cdddc0b..33e3846 100644
--- a/src/main/java/com/squareup/javapoet/CodeBlock.java
+++ b/src/main/java/com/squareup/javapoet/CodeBlock.java
@@ -306,7 +306,7 @@ public final class CodeBlock {
           }
         }
         String s = unused.size() == 1 ? "" : "s";
-        checkArgument(unused.isEmpty(), "unused argument%s: %s", s, Util.join(", ", unused));
+        checkArgument(unused.isEmpty(), "unused argument%s: %s", s, String.join(", ", unused));
       }
       return this;
     }
diff --git a/src/main/java/com/squareup/javapoet/CodeWriter.java b/src/main/java/com/squareup/javapoet/CodeWriter.java
index 4743ea9..9468a08 100644
--- a/src/main/java/com/squareup/javapoet/CodeWriter.java
+++ b/src/main/java/com/squareup/javapoet/CodeWriter.java
@@ -33,8 +33,8 @@ import javax.lang.model.element.Modifier;
 import static com.squareup.javapoet.Util.checkArgument;
 import static com.squareup.javapoet.Util.checkNotNull;
 import static com.squareup.javapoet.Util.checkState;
-import static com.squareup.javapoet.Util.join;
 import static com.squareup.javapoet.Util.stringLiteralWithDoubleQuotes;
+import static java.lang.String.join;
 
 /**
  * Converts a {@link JavaFile} to a string suitable to both human- and javac-consumption. This
@@ -67,11 +67,11 @@ final class CodeWriter {
   int statementLine = -1;
 
   CodeWriter(Appendable out) {
-    this(out, "  ", Collections.<String>emptySet());
+    this(out, "  ", Collections.emptySet());
   }
 
   CodeWriter(Appendable out, String indent, Set<String> staticImports) {
-    this(out, indent, Collections.<String, ClassName>emptyMap(), staticImports);
+    this(out, indent, Collections.emptyMap(), staticImports);
   }
 
   CodeWriter(Appendable out, String indent, Map<String, ClassName> importedTypes,
@@ -177,7 +177,7 @@ final class CodeWriter {
   }
 
   public void emitModifiers(Set<Modifier> modifiers) throws IOException {
-    emitModifiers(modifiers, Collections.<Modifier>emptySet());
+    emitModifiers(modifiers, Collections.emptySet());
   }
 
   /**
@@ -339,7 +339,7 @@ final class CodeWriter {
   private void emitLiteral(Object o) throws IOException {
     if (o instanceof TypeSpec) {
       TypeSpec typeSpec = (TypeSpec) o;
-      typeSpec.emit(this, null, Collections.<Modifier>emptySet());
+      typeSpec.emit(this, null, Collections.emptySet());
     } else if (o instanceof AnnotationSpec) {
       AnnotationSpec annotationSpec = (AnnotationSpec) o;
       annotationSpec.emit(this, true);
diff --git a/src/main/java/com/squareup/javapoet/FieldSpec.java b/src/main/java/com/squareup/javapoet/FieldSpec.java
index 5e3e630..851b36d 100644
--- a/src/main/java/com/squareup/javapoet/FieldSpec.java
+++ b/src/main/java/com/squareup/javapoet/FieldSpec.java
@@ -79,7 +79,7 @@ public final class FieldSpec {
     StringBuilder out = new StringBuilder();
     try {
       CodeWriter codeWriter = new CodeWriter(out);
-      emit(codeWriter, Collections.<Modifier>emptySet());
+      emit(codeWriter, Collections.emptySet());
       return out.toString();
     } catch (IOException e) {
       throw new AssertionError();
diff --git a/src/main/java/com/squareup/javapoet/JavaFile.java b/src/main/java/com/squareup/javapoet/JavaFile.java
index 4852f87..b6b5a75 100644
--- a/src/main/java/com/squareup/javapoet/JavaFile.java
+++ b/src/main/java/com/squareup/javapoet/JavaFile.java
@@ -32,7 +32,6 @@ import java.util.Set;
 import java.util.TreeSet;
 import javax.annotation.processing.Filer;
 import javax.lang.model.element.Element;
-import javax.lang.model.element.Modifier;
 import javax.tools.JavaFileObject;
 import javax.tools.JavaFileObject.Kind;
 import javax.tools.SimpleJavaFileObject;
@@ -154,7 +153,7 @@ public final class JavaFile {
       codeWriter.emit("\n");
     }
 
-    typeSpec.emit(codeWriter, null, Collections.<Modifier>emptySet());
+    typeSpec.emit(codeWriter, null, Collections.emptySet());
 
     codeWriter.popPackage();
   }
diff --git a/src/main/java/com/squareup/javapoet/MethodSpec.java b/src/main/java/com/squareup/javapoet/MethodSpec.java
index 0073445..eff5410 100644
--- a/src/main/java/com/squareup/javapoet/MethodSpec.java
+++ b/src/main/java/com/squareup/javapoet/MethodSpec.java
@@ -161,7 +161,7 @@ public final class MethodSpec {
     StringBuilder out = new StringBuilder();
     try {
       CodeWriter codeWriter = new CodeWriter(out);
-      emit(codeWriter, "Constructor", Collections.<Modifier>emptySet());
+      emit(codeWriter, "Constructor", Collections.emptySet());
       return out.toString();
     } catch (IOException e) {
       throw new AssertionError();
@@ -202,7 +202,7 @@ public final class MethodSpec {
 
     modifiers = new LinkedHashSet<>(modifiers);
     modifiers.remove(Modifier.ABSTRACT);
-    modifiers.remove(Util.DEFAULT); // LinkedHashSet permits null as element for Java 7
+    modifiers.remove(Modifier.DEFAULT);
     methodBuilder.addModifiers(modifiers);
 
     for (TypeParameterElement typeParameterElement : method.getTypeParameters()) {
diff --git a/src/main/java/com/squareup/javapoet/NameAllocator.java b/src/main/java/com/squareup/javapoet/NameAllocator.java
index 961cba5..8269664 100644
--- a/src/main/java/com/squareup/javapoet/NameAllocator.java
+++ b/src/main/java/com/squareup/javapoet/NameAllocator.java
@@ -83,7 +83,7 @@ public final class NameAllocator implements Cloneable {
   private final Map<Object, String> tagToName;
 
   public NameAllocator() {
-    this(new LinkedHashSet<String>(), new LinkedHashMap<Object, String>());
+    this(new LinkedHashSet<>(), new LinkedHashMap<>());
   }
 
   private NameAllocator(LinkedHashSet<String> allocatedNames,
diff --git a/src/main/java/com/squareup/javapoet/ParameterizedTypeName.java b/src/main/java/com/squareup/javapoet/ParameterizedTypeName.java
index aadb9ae..d46aba8 100644
--- a/src/main/java/com/squareup/javapoet/ParameterizedTypeName.java
+++ b/src/main/java/com/squareup/javapoet/ParameterizedTypeName.java
@@ -35,7 +35,7 @@ public final class ParameterizedTypeName extends TypeName {
 
   ParameterizedTypeName(ParameterizedTypeName enclosingType, ClassName rawType,
       List<TypeName> typeArguments) {
-    this(enclosingType, rawType, typeArguments, new ArrayList<AnnotationSpec>());
+    this(enclosingType, rawType, typeArguments, new ArrayList<>());
   }
 
   private ParameterizedTypeName(ParameterizedTypeName enclosingType, ClassName rawType,
@@ -59,8 +59,7 @@ public final class ParameterizedTypeName extends TypeName {
   }
 
   @Override public TypeName withoutAnnotations() {
-    return new ParameterizedTypeName(
-        enclosingType, rawType, typeArguments, new ArrayList<AnnotationSpec>());
+    return new ParameterizedTypeName(enclosingType, rawType, typeArguments, new ArrayList<>());
   }
 
   @Override CodeWriter emit(CodeWriter out) throws IOException {
@@ -92,8 +91,8 @@ public final class ParameterizedTypeName extends TypeName {
    */
   public ParameterizedTypeName nestedClass(String name) {
     checkNotNull(name, "name == null");
-    return new ParameterizedTypeName(this, rawType.nestedClass(name), new ArrayList<TypeName>(),
-        new ArrayList<AnnotationSpec>());
+    return new ParameterizedTypeName(this, rawType.nestedClass(name), new ArrayList<>(),
+        new ArrayList<>());
   }
 
   /**
@@ -103,7 +102,7 @@ public final class ParameterizedTypeName extends TypeName {
   public ParameterizedTypeName nestedClass(String name, List<TypeName> typeArguments) {
     checkNotNull(name, "name == null");
     return new ParameterizedTypeName(this, rawType.nestedClass(name), typeArguments,
-        new ArrayList<AnnotationSpec>());
+        new ArrayList<>());
   }
 
   /** Returns a parameterized type, applying {@code typeArguments} to {@code rawType}. */
@@ -118,7 +117,7 @@ public final class ParameterizedTypeName extends TypeName {
 
   /** Returns a parameterized type equivalent to {@code type}. */
   public static ParameterizedTypeName get(ParameterizedType type) {
-    return get(type, new LinkedHashMap<Type, TypeVariableName>());
+    return get(type, new LinkedHashMap<>());
   }
 
   /** Returns a parameterized type equivalent to {@code type}. */
diff --git a/src/main/java/com/squareup/javapoet/TypeName.java b/src/main/java/com/squareup/javapoet/TypeName.java
index 401887d..e09d785 100644
--- a/src/main/java/com/squareup/javapoet/TypeName.java
+++ b/src/main/java/com/squareup/javapoet/TypeName.java
@@ -36,7 +36,7 @@ import javax.lang.model.type.NoType;
 import javax.lang.model.type.PrimitiveType;
 import javax.lang.model.type.TypeKind;
 import javax.lang.model.type.TypeMirror;
-import javax.lang.model.util.SimpleTypeVisitor7;
+import javax.lang.model.util.SimpleTypeVisitor8;
 
 /**
  * Any type in Java's type system, plus {@code void}. This class is an identifier for primitive
@@ -95,7 +95,7 @@ public class TypeName {
   private String cachedString;
 
   private TypeName(String keyword) {
-    this(keyword, new ArrayList<AnnotationSpec>());
+    this(keyword, new ArrayList<>());
   }
 
   private TypeName(String keyword, List<AnnotationSpec> annotations) {
@@ -235,12 +235,12 @@ public class TypeName {
 
   /** Returns a type name equivalent to {@code mirror}. */
   public static TypeName get(TypeMirror mirror) {
-    return get(mirror, new LinkedHashMap<TypeParameterElement, TypeVariableName>());
+    return get(mirror, new LinkedHashMap<>());
   }
 
   static TypeName get(TypeMirror mirror,
       final Map<TypeParameterElement, TypeVariableName> typeVariables) {
-    return mirror.accept(new SimpleTypeVisitor7<TypeName, Void>() {
+    return mirror.accept(new SimpleTypeVisitor8<TypeName, Void>() {
       @Override public TypeName visitPrimitive(PrimitiveType t, Void p) {
         switch (t.getKind()) {
           case BOOLEAN:
@@ -315,7 +315,7 @@ public class TypeName {
 
   /** Returns a type name equivalent to {@code type}. */
   public static TypeName get(Type type) {
-    return get(type, new LinkedHashMap<Type, TypeVariableName>());
+    return get(type, new LinkedHashMap<>());
   }
 
   static TypeName get(Type type, Map<Type, TypeVariableName> map) {
@@ -352,7 +352,7 @@ public class TypeName {
 
   /** Converts an array of types to a list of type names. */
   static List<TypeName> list(Type[] types) {
-    return list(types, new LinkedHashMap<Type, TypeVariableName>());
+    return list(types, new LinkedHashMap<>());
   }
 
   static List<TypeName> list(Type[] types, Map<Type, TypeVariableName> map) {
diff --git a/src/main/java/com/squareup/javapoet/TypeSpec.java b/src/main/java/com/squareup/javapoet/TypeSpec.java
index 73052d0..feac8ef 100644
--- a/src/main/java/com/squareup/javapoet/TypeSpec.java
+++ b/src/main/java/com/squareup/javapoet/TypeSpec.java
@@ -34,7 +34,6 @@ import javax.lang.model.element.Modifier;
 import static com.squareup.javapoet.Util.checkArgument;
 import static com.squareup.javapoet.Util.checkNotNull;
 import static com.squareup.javapoet.Util.checkState;
-import static com.squareup.javapoet.Util.hasDefaultModifier;
 import static com.squareup.javapoet.Util.requireExactlyOneOf;
 
 /** A generated class, interface, or enum declaration. */
@@ -215,7 +214,7 @@ public final class TypeSpec {
           implementsTypes = Collections.emptyList();
         } else {
           extendsTypes = superclass.equals(ClassName.OBJECT)
-              ? Collections.<TypeName>emptyList()
+              ? Collections.emptyList()
               : Collections.singletonList(superclass);
           implementsTypes = superinterfaces;
         }
@@ -252,8 +251,7 @@ public final class TypeSpec {
           i.hasNext(); ) {
         Map.Entry<String, TypeSpec> enumConstant = i.next();
         if (!firstMember) codeWriter.emit("\n");
-        enumConstant.getValue()
-            .emit(codeWriter, enumConstant.getKey(), Collections.<Modifier>emptySet());
+        enumConstant.getValue().emit(codeWriter, enumConstant.getKey(), Collections.emptySet());
         firstMember = false;
         if (i.hasNext()) {
           codeWriter.emit(",\n");
@@ -343,7 +341,7 @@ public final class TypeSpec {
     StringBuilder out = new StringBuilder();
     try {
       CodeWriter codeWriter = new CodeWriter(out);
-      emit(codeWriter, null, Collections.<Modifier>emptySet());
+      emit(codeWriter, null, Collections.emptySet());
       return out.toString();
     } catch (IOException e) {
       throw new AssertionError();
@@ -352,28 +350,28 @@ public final class TypeSpec {
 
   public enum Kind {
     CLASS(
-        Collections.<Modifier>emptySet(),
-        Collections.<Modifier>emptySet(),
-        Collections.<Modifier>emptySet(),
-        Collections.<Modifier>emptySet()),
+        Collections.emptySet(),
+        Collections.emptySet(),
+        Collections.emptySet(),
+        Collections.emptySet()),
 
     INTERFACE(
         Util.immutableSet(Arrays.asList(Modifier.PUBLIC, Modifier.STATIC, Modifier.FINAL)),
         Util.immutableSet(Arrays.asList(Modifier.PUBLIC, Modifier.ABSTRACT)),
         Util.immutableSet(Arrays.asList(Modifier.PUBLIC, Modifier.STATIC)),
-        Util.immutableSet(Arrays.asList(Modifier.STATIC))),
+        Util.immutableSet(Collections.singletonList(Modifier.STATIC))),
 
     ENUM(
-        Collections.<Modifier>emptySet(),
-        Collections.<Modifier>emptySet(),
-        Collections.<Modifier>emptySet(),
+        Collections.emptySet(),
+        Collections.emptySet(),
+        Collections.emptySet(),
         Collections.singleton(Modifier.STATIC)),
 
     ANNOTATION(
         Util.immutableSet(Arrays.asList(Modifier.PUBLIC, Modifier.STATIC, Modifier.FINAL)),
         Util.immutableSet(Arrays.asList(Modifier.PUBLIC, Modifier.ABSTRACT)),
         Util.immutableSet(Arrays.asList(Modifier.PUBLIC, Modifier.STATIC)),
-        Util.immutableSet(Arrays.asList(Modifier.STATIC)));
+        Util.immutableSet(Collections.singletonList(Modifier.STATIC)));
 
     private final Set<Modifier> implicitFieldModifiers;
     private final Set<Modifier> implicitMethodModifiers;
@@ -571,7 +569,8 @@ public final class TypeSpec {
 
     public Builder addMethod(MethodSpec methodSpec) {
       if (kind == Kind.INTERFACE) {
-        requireExactlyOneOf(methodSpec.modifiers, Modifier.ABSTRACT, Modifier.STATIC, Util.DEFAULT);
+        requireExactlyOneOf(methodSpec.modifiers, Modifier.ABSTRACT, Modifier.STATIC,
+            Modifier.DEFAULT);
         requireExactlyOneOf(methodSpec.modifiers, Modifier.PUBLIC, Modifier.PRIVATE);
       } else if (kind == Kind.ANNOTATION) {
         checkState(methodSpec.modifiers.equals(kind.implicitMethodModifiers),
@@ -583,7 +582,7 @@ public final class TypeSpec {
             kind, name, methodSpec.name);
       }
       if (kind != Kind.INTERFACE) {
-        checkState(!hasDefaultModifier(methodSpec.modifiers), "%s %s.%s cannot be default",
+        checkState(!methodSpec.hasModifier(Modifier.DEFAULT), "%s %s.%s cannot be default",
             kind, name, methodSpec.name);
       }
       methodSpecs.add(methodSpec);
diff --git a/src/main/java/com/squareup/javapoet/TypeVariableName.java b/src/main/java/com/squareup/javapoet/TypeVariableName.java
index b3e3e03..e0e54fb 100644
--- a/src/main/java/com/squareup/javapoet/TypeVariableName.java
+++ b/src/main/java/com/squareup/javapoet/TypeVariableName.java
@@ -36,7 +36,7 @@ public final class TypeVariableName extends TypeName {
   public final List<TypeName> bounds;
 
   private TypeVariableName(String name, List<TypeName> bounds) {
-    this(name, bounds, new ArrayList<AnnotationSpec>());
+    this(name, bounds, new ArrayList<>());
   }
 
   private TypeVariableName(String name, List<TypeName> bounds, List<AnnotationSpec> annotations) {
@@ -85,7 +85,7 @@ public final class TypeVariableName extends TypeName {
 
   /** Returns type variable named {@code name} without bounds. */
   public static TypeVariableName get(String name) {
-    return TypeVariableName.of(name, Collections.<TypeName>emptyList());
+    return TypeVariableName.of(name, Collections.emptyList());
   }
 
   /** Returns type variable named {@code name} with {@code bounds}. */
@@ -145,7 +145,7 @@ public final class TypeVariableName extends TypeName {
 
   /** Returns type variable equivalent to {@code type}. */
   public static TypeVariableName get(java.lang.reflect.TypeVariable<?> type) {
-    return get(type, new LinkedHashMap<Type, TypeVariableName>());
+    return get(type, new LinkedHashMap<>());
   }
 
   /** @see #get(java.lang.reflect.TypeVariable, Map) */
diff --git a/src/main/java/com/squareup/javapoet/Util.java b/src/main/java/com/squareup/javapoet/Util.java
index 15e3909..e0eabad 100644
--- a/src/main/java/com/squareup/javapoet/Util.java
+++ b/src/main/java/com/squareup/javapoet/Util.java
@@ -36,17 +36,6 @@ final class Util {
   private Util() {
   }
 
-  /** Modifier.DEFAULT doesn't exist until Java 8, but we want to run on earlier releases. */
-  static final Modifier DEFAULT;
-  static {
-    Modifier def = null;
-    try {
-      def = Modifier.valueOf("DEFAULT");
-    } catch (IllegalArgumentException ignored) {
-    }
-    DEFAULT = def;
-  }
-
   static <K, V> Map<K, List<V>> immutableMultimap(Map<K, List<V>> multimap) {
     LinkedHashMap<K, List<V>> result = new LinkedHashMap<>();
     for (Map.Entry<K, List<V>> entry : multimap.entrySet()) {
@@ -81,16 +70,6 @@ final class Util {
     return Collections.unmodifiableSet(new LinkedHashSet<>(set));
   }
 
-  static String join(String separator, List<String> parts) {
-    if (parts.isEmpty()) return "";
-    StringBuilder result = new StringBuilder();
-    result.append(parts.get(0));
-    for (int i = 1; i < parts.size(); i++) {
-      result.append(separator).append(parts.get(i));
-    }
-    return result.toString();
-  }
-
   static <T> Set<T> union(Set<T> a, Set<T> b) {
     Set<T> result = new LinkedHashSet<>();
     result.addAll(a);
@@ -101,17 +80,12 @@ final class Util {
   static void requireExactlyOneOf(Set<Modifier> modifiers, Modifier... mutuallyExclusive) {
     int count = 0;
     for (Modifier modifier : mutuallyExclusive) {
-      if (modifier == null && Util.DEFAULT == null) continue; // Skip 'DEFAULT' if it doesn't exist!
       if (modifiers.contains(modifier)) count++;
     }
     checkArgument(count == 1, "modifiers %s must contain one of %s",
         modifiers, Arrays.toString(mutuallyExclusive));
   }
 
-  static boolean hasDefaultModifier(Collection<Modifier> modifiers) {
-    return DEFAULT != null && modifiers.contains(DEFAULT);
-  }
-
   static String characterLiteralWithoutSingleQuotes(char c) {
     // see https://docs.oracle.com/javase/specs/jls/se7/html/jls-3.html#jls-3.10.6
     switch (c) {
diff --git a/src/main/java/com/squareup/javapoet/WildcardTypeName.java b/src/main/java/com/squareup/javapoet/WildcardTypeName.java
index cf33bb8..17cb73f 100644
--- a/src/main/java/com/squareup/javapoet/WildcardTypeName.java
+++ b/src/main/java/com/squareup/javapoet/WildcardTypeName.java
@@ -19,7 +19,6 @@ import java.io.IOException;
 import java.lang.reflect.Type;
 import java.lang.reflect.WildcardType;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -34,7 +33,7 @@ public final class WildcardTypeName extends TypeName {
   public final List<TypeName> lowerBounds;
 
   private WildcardTypeName(List<TypeName> upperBounds, List<TypeName> lowerBounds) {
-    this(upperBounds, lowerBounds, new ArrayList<AnnotationSpec>());
+    this(upperBounds, lowerBounds, new ArrayList<>());
   }
 
   private WildcardTypeName(List<TypeName> upperBounds, List<TypeName> lowerBounds,
@@ -78,7 +77,7 @@ public final class WildcardTypeName extends TypeName {
    * ? extends Object}.
    */
   public static WildcardTypeName subtypeOf(TypeName upperBound) {
-    return new WildcardTypeName(Arrays.asList(upperBound), Collections.<TypeName>emptyList());
+    return new WildcardTypeName(Collections.singletonList(upperBound), Collections.emptyList());
   }
 
   public static WildcardTypeName subtypeOf(Type upperBound) {
@@ -90,7 +89,8 @@ public final class WildcardTypeName extends TypeName {
    * bound} is {@code String.class}, this returns {@code ? super String}.
    */
   public static WildcardTypeName supertypeOf(TypeName lowerBound) {
-    return new WildcardTypeName(Arrays.<TypeName>asList(OBJECT), Arrays.asList(lowerBound));
+    return new WildcardTypeName(Collections.singletonList(OBJECT),
+        Collections.singletonList(lowerBound));
   }
 
   public static WildcardTypeName supertypeOf(Type lowerBound) {
@@ -98,7 +98,7 @@ public final class WildcardTypeName extends TypeName {
   }
 
   public static TypeName get(javax.lang.model.type.WildcardType mirror) {
-    return get(mirror, new LinkedHashMap<TypeParameterElement, TypeVariableName>());
+    return get(mirror, new LinkedHashMap<>());
   }
 
   static TypeName get(
@@ -118,7 +118,7 @@ public final class WildcardTypeName extends TypeName {
   }
 
   public static TypeName get(WildcardType wildcardName) {
-    return get(wildcardName, new LinkedHashMap<Type, TypeVariableName>());
+    return get(wildcardName, new LinkedHashMap<>());
   }
 
   static TypeName get(WildcardType wildcardName, Map<Type, TypeVariableName> map) {
diff --git a/src/test/java/com/squareup/javapoet/AnnotatedTypeNameTest.java b/src/test/java/com/squareup/javapoet/AnnotatedTypeNameTest.java
index 142af72..18b7f7e 100644
--- a/src/test/java/com/squareup/javapoet/AnnotatedTypeNameTest.java
+++ b/src/test/java/com/squareup/javapoet/AnnotatedTypeNameTest.java
@@ -20,6 +20,8 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertTrue;
 
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
 import java.util.List;
 import java.util.Map;
 import org.junit.Ignore;
@@ -115,7 +117,7 @@ public class AnnotatedTypeNameTest {
   }
 
   // https://github.com/square/javapoet/issues/431
-  // @Target(ElementType.TYPE_USE) requires Java 1.8
+  @Target(ElementType.TYPE_USE)
   public @interface TypeUseAnnotation {}
 
   // https://github.com/square/javapoet/issues/431
diff --git a/src/test/java/com/squareup/javapoet/FileReadingTest.java b/src/test/java/com/squareup/javapoet/FileReadingTest.java
index 27041a0..eb19de0 100644
--- a/src/test/java/com/squareup/javapoet/FileReadingTest.java
+++ b/src/test/java/com/squareup/javapoet/FileReadingTest.java
@@ -105,8 +105,8 @@ public class FileReadingTest {
     CompilationTask task = compiler.getTask(null, 
         fileManager,
         diagnosticCollector,
-        Collections.<String>emptySet(),
-        Collections.<String>emptySet(),
+        Collections.emptySet(),
+        Collections.emptySet(),
         Collections.singleton(javaFile.toJavaFileObject()));
     
     assertThat(task.call()).isTrue();
diff --git a/src/test/java/com/squareup/javapoet/MethodSpecTest.java b/src/test/java/com/squareup/javapoet/MethodSpecTest.java
index 1a7205c..96923eb 100644
--- a/src/test/java/com/squareup/javapoet/MethodSpecTest.java
+++ b/src/test/java/com/squareup/javapoet/MethodSpecTest.java
@@ -39,7 +39,6 @@ import org.junit.Test;
 
 import static com.google.common.collect.Iterables.getOnlyElement;
 import static com.google.common.truth.Truth.assertThat;
-import static com.google.common.truth.TruthJUnit.assume;
 import static javax.lang.model.util.ElementFilter.methodsIn;
 import static org.junit.Assert.fail;
 import static org.mockito.Mockito.mock;
@@ -152,7 +151,6 @@ public final class MethodSpecTest {
     DeclaredType classType = (DeclaredType) classElement.asType();
     List<ExecutableElement> methods = methodsIn(elements.getAllMembers(classElement));
     ExecutableElement exec = findFirst(methods, "iterator");
-    assume().that(Util.DEFAULT).isNotNull();
     exec = findFirst(methods, "spliterator");
     MethodSpec method = MethodSpec.overriding(exec, classType, types).build();
     assertThat(method.toString()).isEqualTo(""
diff --git a/src/test/java/com/squareup/javapoet/TypeSpecTest.java b/src/test/java/com/squareup/javapoet/TypeSpecTest.java
index 145d9bc..5d87582 100644
--- a/src/test/java/com/squareup/javapoet/TypeSpecTest.java
+++ b/src/test/java/com/squareup/javapoet/TypeSpecTest.java
@@ -44,7 +44,6 @@ import org.mockito.Mockito;
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
-import static org.junit.Assume.assumeTrue;
 
 @RunWith(JUnit4.class)
 public final class TypeSpecTest {
@@ -57,10 +56,6 @@ public final class TypeSpecTest {
     return compilation.getElements().getTypeElement(clazz.getCanonicalName());
   }
 
-  private boolean isJava8() {
-    return Util.DEFAULT != null;
-  }
-
   @Test public void basic() throws Exception {
     TypeSpec taco = TypeSpec.classBuilder("Taco")
         .addMethod(MethodSpec.methodBuilder("toString")
@@ -832,11 +827,10 @@ public final class TypeSpecTest {
 
   @Test
   public void classCannotHaveDefaultMethods() throws Exception {
-    assumeTrue(isJava8());
     try {
       TypeSpec.classBuilder("Tacos")
           .addMethod(MethodSpec.methodBuilder("test")
-              .addModifiers(Modifier.PUBLIC, Modifier.valueOf("DEFAULT"))
+              .addModifiers(Modifier.PUBLIC, Modifier.DEFAULT)
               .returns(int.class)
               .addCode(CodeBlock.builder().addStatement("return 0").build())
               .build())
@@ -869,10 +863,9 @@ public final class TypeSpecTest {
 
   @Test
   public void interfaceDefaultMethods() throws Exception {
-    assumeTrue(isJava8());
     TypeSpec bar = TypeSpec.interfaceBuilder("Tacos")
         .addMethod(MethodSpec.methodBuilder("test")
-            .addModifiers(Modifier.PUBLIC, Modifier.valueOf("DEFAULT"))
+            .addModifiers(Modifier.PUBLIC, Modifier.DEFAULT)
             .returns(int.class)
             .addCode(CodeBlock.builder().addStatement("return 0").build())
             .build())
diff --git a/src/test/java/com/squareup/javapoet/TypesEclipseTest.java b/src/test/java/com/squareup/javapoet/TypesEclipseTest.java
index 96b846b..2759f17 100644
--- a/src/test/java/com/squareup/javapoet/TypesEclipseTest.java
+++ b/src/test/java/com/squareup/javapoet/TypesEclipseTest.java
@@ -65,7 +65,7 @@ public final class TypesEclipseTest extends AbstractTypesTest {
     public Statement apply(final Statement base, Description description) {
       return new Statement() {
         @Override public void evaluate() throws Throwable {
-          final AtomicReference<Throwable> thrown = new AtomicReference<Throwable>();
+          final AtomicReference<Throwable> thrown = new AtomicReference<>();
           boolean successful = compile(ImmutableList.of(new AbstractProcessor() {
             @Override
             public SourceVersion getSupportedSourceVersion() {
@@ -130,15 +130,15 @@ public final class TypesEclipseTest extends AbstractTypesTest {
     static private boolean compile(Iterable<? extends Processor> processors) {
       JavaCompiler compiler = new EclipseCompiler();
       DiagnosticCollector<JavaFileObject> diagnosticCollector =
-          new DiagnosticCollector<JavaFileObject>();
+          new DiagnosticCollector<>();
       JavaFileManager fileManager = compiler.getStandardFileManager(diagnosticCollector, Locale.getDefault(), UTF_8);
       JavaCompiler.CompilationTask task = compiler.getTask(
           null,
           fileManager,
           diagnosticCollector,
-          ImmutableSet.<String>of(),
+          ImmutableSet.of(),
           ImmutableSet.of(TypesEclipseTest.class.getCanonicalName()),
-          ImmutableSet.<JavaFileObject>of());
+          ImmutableSet.of());
       task.setProcessors(processors);
       return task.call();
     }