Merge pull request #1637 from harawata/default-method-jdk9

 Avoid illegal reflective access on default method invocation

Author: harawata

src/main/java/org/apache/ibatis/binding/MapperProxy.java

@@ -18,6 +18,7 @@
 import java.io.Serializable;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodHandles.Lookup;
+import java.lang.invoke.MethodType;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.Method;
@@ -35,7 +36,8 @@ public class MapperProxy<T> implements InvocationHandler, Serializable {
   private static final long serialVersionUID = -6424540398559729838L;
   private static final int ALLOWED_MODES = MethodHandles.Lookup.PRIVATE | MethodHandles.Lookup.PROTECTED
       | MethodHandles.Lookup.PACKAGE | MethodHandles.Lookup.PUBLIC;
-  private static Constructor<Lookup> lookupConstructor;
+  private static final Constructor<Lookup> lookupConstructor;
+  private static final Method privateLookupInMethod;
   private final SqlSession sqlSession;
   private final Class<T> mapperInterface;
   private final Map<Method, MapperMethod> methodCache;
@@ -47,17 +49,29 @@ public MapperProxy(SqlSession sqlSession, Class<T> mapperInterface, Map<Method,
   }
 
   static {
+    Method privateLookupIn;
     try {
-      lookupConstructor = MethodHandles.Lookup.class.getDeclaredConstructor(Class.class, int.class);
+      privateLookupIn = MethodHandles.class.getMethod("privateLookupIn", Class.class, MethodHandles.Lookup.class);
     } catch (NoSuchMethodException e) {
+      privateLookupIn = null;
+    }
+    privateLookupInMethod = privateLookupIn;
+
+    Constructor<Lookup> lookup = null;
+    if (privateLookupInMethod == null) {
+      // JDK 1.8
       try {
-        // Since Java 14+8
-        lookupConstructor = MethodHandles.Lookup.class.getDeclaredConstructor(Class.class, Class.class, int.class);
-      } catch (NoSuchMethodException e2) {
-        throw new IllegalStateException("No known constructor found in java.lang.invoke.MethodHandles.Lookup.", e2);
+        lookup = MethodHandles.Lookup.class.getDeclaredConstructor(Class.class, int.class);
+        lookup.setAccessible(true);
+      } catch (NoSuchMethodException e) {
+        throw new IllegalStateException(
+            "There is neither 'privateLookupIn(Class, Lookup)' nor 'Lookup(Class, int)' method in java.lang.invoke.MethodHandles.",
+            e);
+      } catch (Throwable t) {
+        lookup = null;
       }
     }
-    lookupConstructor.setAccessible(true);
+    lookupConstructor = lookup;
   }
 
   @Override
@@ -66,7 +80,11 @@ public Object invoke(Object proxy, Method method, Object[] args) throws Throwabl
       if (Object.class.equals(method.getDeclaringClass())) {
         return method.invoke(this, args);
       } else if (method.isDefault()) {
-        return invokeDefaultMethod(proxy, method, args);
+        if (privateLookupInMethod == null) {
+          return invokeDefaultMethodJava8(proxy, method, args);
+        } else {
+          return invokeDefaultMethodJava9(proxy, method, args);
+        }
       }
     } catch (Throwable t) {
       throw ExceptionUtil.unwrapThrowable(t);
@@ -76,19 +94,23 @@ public Object invoke(Object proxy, Method method, Object[] args) throws Throwabl
   }
 
   private MapperMethod cachedMapperMethod(Method method) {
-    return methodCache.computeIfAbsent(method, k -> new MapperMethod(mapperInterface, method, sqlSession.getConfiguration()));
+    return methodCache.computeIfAbsent(method,
+        k -> new MapperMethod(mapperInterface, method, sqlSession.getConfiguration()));
   }
 
-  private Object invokeDefaultMethod(Object proxy, Method method, Object[] args)
+  private Object invokeDefaultMethodJava9(Object proxy, Method method, Object[] args)
       throws Throwable {
     final Class<?> declaringClass = method.getDeclaringClass();
-    final Lookup lookup;
-    if (lookupConstructor.getParameterCount() == 2) {
-      lookup = lookupConstructor.newInstance(declaringClass, ALLOWED_MODES);
-    } else {
-      // SInce JDK 14+8
-      lookup = lookupConstructor.newInstance(declaringClass, null, ALLOWED_MODES);
-    }
-    return lookup.unreflectSpecial(method, declaringClass).bindTo(proxy).invokeWithArguments(args);
+    return ((Lookup) privateLookupInMethod.invoke(null, declaringClass, MethodHandles.lookup()))
+        .findSpecial(declaringClass, method.getName(),
+            MethodType.methodType(method.getReturnType(), method.getParameterTypes()), declaringClass)
+        .bindTo(proxy).invokeWithArguments(args);
+  }
+
+  private Object invokeDefaultMethodJava8(Object proxy, Method method, Object[] args)
+      throws Throwable {
+    final Class<?> declaringClass = method.getDeclaringClass();
+    return lookupConstructor.newInstance(declaringClass, ALLOWED_MODES).unreflectSpecial(method, declaringClass)
+        .bindTo(proxy).invokeWithArguments(args);
   }
 }