/*

 * Copyright (c) 2008, 2021, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package java.lang.invoke;

import jdk.internal.access.SharedSecrets;

import jdk.internal.misc.Unsafe;

import jdk.internal.misc.VM;

import jdk.internal.org.objectweb.asm.ClassReader;

import jdk.internal.org.objectweb.asm.Opcodes;

import jdk.internal.org.objectweb.asm.Type;

import jdk.internal.reflect.CallerSensitive;

import jdk.internal.reflect.Reflection;

import jdk.internal.vm.annotation.ForceInline;

import sun.invoke.util.ValueConversions;

import sun.invoke.util.VerifyAccess;

import sun.invoke.util.Wrapper;

import sun.reflect.misc.ReflectUtil;

import sun.security.util.SecurityConstants;

import java.lang.constant.ConstantDescs;

import java.lang.invoke.LambdaForm.BasicType;

import java.lang.reflect.Constructor;

import java.lang.reflect.Field;

import java.lang.reflect.Member;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

import java.lang.reflect.ReflectPermission;

import java.nio.ByteOrder;

import java.security.ProtectionDomain;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.BitSet;

import java.util.Iterator;

import java.util.List;

import java.util.Objects;

import java.util.Set;

import java.util.concurrent.ConcurrentHashMap;

import java.util.stream.Stream;

import static java.lang.invoke.LambdaForm.BasicType.V_TYPE;

import static java.lang.invoke.MethodHandleImpl.Intrinsic;

import static java.lang.invoke.MethodHandleNatives.Constants.*;

import static java.lang.invoke.MethodHandleStatics.newIllegalArgumentException;

import static java.lang.invoke.MethodType.methodType;

/**

 * This class consists exclusively of static methods that operate on or return

 * method handles. They fall into several categories:

 * <ul>

 * <li>Lookup methods which help create method handles for methods and fields.

 * <li>Combinator methods, which combine or transform pre-existing method handles into new ones.

 * <li>Other factory methods to create method handles that emulate other common JVM operations or control flow patterns.

 * </ul>

 * A lookup, combinator, or factory method will fail and throw an

 * {@code IllegalArgumentException} if the created method handle's type

 * would have <a href="MethodHandle.html#maxarity">too many parameters</a>.

 *

 * @author John Rose, JSR 292 EG

 * @since 1.7

 */

public class MethodHandles {

    private MethodHandles() { }  // do not instantiate

    static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();

    // See IMPL_LOOKUP below.

    //// Method handle creation from ordinary methods.

    /**

     * Returns a {@link Lookup lookup object} with

     * full capabilities to emulate all supported bytecode behaviors of the caller.

     * These capabilities include {@linkplain Lookup#hasFullPrivilegeAccess() full privilege access} to the caller.

     * Factory methods on the lookup object can create

     * <a href="MethodHandleInfo.html#directmh">direct method handles</a>

     * for any member that the caller has access to via bytecodes,

     * including protected and private fields and methods.

     * This lookup object is created by the original lookup class

     * and has the {@link Lookup#ORIGINAL ORIGINAL} bit set.

     * This lookup object is a <em>capability</em> which may be delegated to trusted agents.

     * Do not store it in place where untrusted code can access it.

     * <p>

     * This method is caller sensitive, which means that it may return different

     * values to different callers.

     * @return a lookup object for the caller of this method, with

     * {@linkplain Lookup#ORIGINAL original} and

     * {@linkplain Lookup#hasFullPrivilegeAccess() full privilege access}.

     */

    @CallerSensitive

    @ForceInline // to ensure Reflection.getCallerClass optimization

    public static Lookup lookup() {

        return new Lookup(Reflection.getCallerClass());

    }

    /**

     * This reflected$lookup method is the alternate implementation of

     * the lookup method when being invoked by reflection.

     */

    @CallerSensitive

    private static Lookup reflected$lookup() {

        Class<?> caller = Reflection.getCallerClass();

        if (caller.getClassLoader() == null) {

            throw newIllegalArgumentException("illegal lookupClass: "+caller);

        }

        return new Lookup(caller);

    }

    /**

     * Returns a {@link Lookup lookup object} which is trusted minimally.

     * The lookup has the {@code UNCONDITIONAL} mode.

     * It can only be used to create method handles to public members of

     * public classes in packages that are exported unconditionally.

     * <p>

     * As a matter of pure convention, the {@linkplain Lookup#lookupClass() lookup class}

     * of this lookup object will be {@link java.lang.Object}.

     *

     * @apiNote The use of Object is conventional, and because the lookup modes are

     * limited, there is no special access provided to the internals of Object, its package

     * or its module.  This public lookup object or other lookup object with

     * {@code UNCONDITIONAL} mode assumes readability. Consequently, the lookup class

     * is not used to determine the lookup context.

     *

     * <p style="font-size:smaller;">

     * <em>Discussion:</em>

     * The lookup class can be changed to any other class {@code C} using an expression of the form

     * {@link Lookup#in publicLookup().in(C.class)}.

     * A public lookup object is always subject to

     * <a href="MethodHandles.Lookup.html#secmgr">security manager checks</a>.

     * Also, it cannot access

     * <a href="MethodHandles.Lookup.html#callsens">caller sensitive methods</a>.

     * @return a lookup object which is trusted minimally

     *

     * @revised 9

     */

    public static Lookup publicLookup() {

        return Lookup.PUBLIC_LOOKUP;

    }

    /**

     * Returns a {@link Lookup lookup} object on a target class to emulate all supported

     * bytecode behaviors, including <a href="MethodHandles.Lookup.html#privacc">private access</a>.

     * The returned lookup object can provide access to classes in modules and packages,

     * and members of those classes, outside the normal rules of Java access control,

     * instead conforming to the more permissive rules for modular <em>deep reflection</em>.

     * <p>

     * A caller, specified as a {@code Lookup} object, in module {@code M1} is

     * allowed to do deep reflection on module {@code M2} and package of the target class

     * if and only if all of the following conditions are {@code true}:

     * <ul>

     * <li>If there is a security manager, its {@code checkPermission} method is

     * called to check {@code ReflectPermission("suppressAccessChecks")} and

     * that must return normally.

     * <li>The caller lookup object must have {@linkplain Lookup#hasFullPrivilegeAccess()

     * full privilege access}.  Specifically:

     *   <ul>

     *     <li>The caller lookup object must have the {@link Lookup#MODULE MODULE} lookup mode.

     *         (This is because otherwise there would be no way to ensure the original lookup

     *         creator was a member of any particular module, and so any subsequent checks

     *         for readability and qualified exports would become ineffective.)

     *     <li>The caller lookup object must have {@link Lookup#PRIVATE PRIVATE} access.

     *         (This is because an application intending to share intra-module access

     *         using {@link Lookup#MODULE MODULE} alone will inadvertently also share

     *         deep reflection to its own module.)

     *   </ul>

     * <li>The target class must be a proper class, not a primitive or array class.

     * (Thus, {@code M2} is well-defined.)

     * <li>If the caller module {@code M1} differs from

     * the target module {@code M2} then both of the following must be true:

     *   <ul>

     *     <li>{@code M1} {@link Module#canRead reads} {@code M2}.</li>

     *     <li>{@code M2} {@link Module#isOpen(String,Module) opens} the package

     *         containing the target class to at least {@code M1}.</li>

     *   </ul>

     * </ul>

     * <p>

     * If any of the above checks is violated, this method fails with an

     * exception.

     * <p>

     * Otherwise, if {@code M1} and {@code M2} are the same module, this method

     * returns a {@code Lookup} on {@code targetClass} with

     * {@linkplain Lookup#hasFullPrivilegeAccess() full privilege access}

     * with {@code null} previous lookup class.

     * <p>

     * Otherwise, {@code M1} and {@code M2} are two different modules.  This method

     * returns a {@code Lookup} on {@code targetClass} that records

     * the lookup class of the caller as the new previous lookup class with

     * {@code PRIVATE} access but no {@code MODULE} access.

     * <p>

     * The resulting {@code Lookup} object has no {@code ORIGINAL} access.

     *

     * @param targetClass the target class

     * @param caller the caller lookup object

     * @return a lookup object for the target class, with private access

     * @throws IllegalArgumentException if {@code targetClass} is a primitive type or void or array class

     * @throws NullPointerException if {@code targetClass} or {@code caller} is {@code null}

     * @throws SecurityException if denied by the security manager

     * @throws IllegalAccessException if any of the other access checks specified above fails

     * @since 9

     * @see Lookup#dropLookupMode

     * @see <a href="MethodHandles.Lookup.html#cross-module-lookup">Cross-module lookups</a>

     */

    public static Lookup privateLookupIn(Class<?> targetClass, Lookup caller) throws IllegalAccessException {

        if (caller.allowedModes == Lookup.TRUSTED) {

            return new Lookup(targetClass);

        }

        @SuppressWarnings("removal")

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) sm.checkPermission(ACCESS_PERMISSION);

        if (targetClass.isPrimitive())

            throw new IllegalArgumentException(targetClass + " is a primitive class");

        if (targetClass.isArray())

            throw new IllegalArgumentException(targetClass + " is an array class");

        // Ensure that we can reason accurately about private and module access.

        int requireAccess = Lookup.PRIVATE|Lookup.MODULE;

        if ((caller.lookupModes() & requireAccess) != requireAccess)

            throw new IllegalAccessException("caller does not have PRIVATE and MODULE lookup mode");

        // previous lookup class is never set if it has MODULE access

        assert caller.previousLookupClass() == null;

        Class<?> callerClass = caller.lookupClass();

        Module callerModule = callerClass.getModule();  // M1

        Module targetModule = targetClass.getModule();  // M2

        Class<?> newPreviousClass = null;

        int newModes = Lookup.FULL_POWER_MODES & ~Lookup.ORIGINAL;

        if (targetModule != callerModule) {

            if (!callerModule.canRead(targetModule))

                throw new IllegalAccessException(callerModule + " does not read " + targetModule);

            if (targetModule.isNamed()) {

                String pn = targetClass.getPackageName();

                assert !pn.isEmpty() : "unnamed package cannot be in named module";

                if (!targetModule.isOpen(pn, callerModule))

                    throw new IllegalAccessException(targetModule + " does not open " + pn + " to " + callerModule);

            }

            // M2 != M1, set previous lookup class to M1 and drop MODULE access

            newPreviousClass = callerClass;

            newModes &= ~Lookup.MODULE;

        }

        return Lookup.newLookup(targetClass, newPreviousClass, newModes);

    }

    /**

     * Returns the <em>class data</em> associated with the lookup class

     * of the given {@code caller} lookup object, or {@code null}.

     *

     * <p> A hidden class with class data can be created by calling

     * {@link Lookup#defineHiddenClassWithClassData(byte[], Object, boolean, Lookup.ClassOption...)

     * Lookup::defineHiddenClassWithClassData}.

     * This method will cause the static class initializer of the lookup

     * class of the given {@code caller} lookup object be executed if

     * it has not been initialized.

     *

     * <p> A hidden class created by {@link Lookup#defineHiddenClass(byte[], boolean, Lookup.ClassOption...)

     * Lookup::defineHiddenClass} and non-hidden classes have no class data.

     * {@code null} is returned if this method is called on the lookup object

     * on these classes.

     *

     * <p> The {@linkplain Lookup#lookupModes() lookup modes} for this lookup

     * must have {@linkplain Lookup#ORIGINAL original access}

     * in order to retrieve the class data.

     *

     * @apiNote

     * This method can be called as a bootstrap method for a dynamically computed

     * constant.  A framework can create a hidden class with class data, for

     * example that can be {@code Class} or {@code MethodHandle} object.

     * The class data is accessible only to the lookup object

     * created by the original caller but inaccessible to other members

     * in the same nest.  If a framework passes security sensitive objects

     * to a hidden class via class data, it is recommended to load the value

     * of class data as a dynamically computed constant instead of storing

     * the class data in private static field(s) which are accessible to

     * other nestmates.

     *

     * @param <T> the type to cast the class data object to

     * @param caller the lookup context describing the class performing the

     * operation (normally stacked by the JVM)

     * @param name must be {@link ConstantDescs#DEFAULT_NAME}

     *             ({@code "_"})

     * @param type the type of the class data

     * @return the value of the class data if present in the lookup class;

     * otherwise {@code null}

     * @throws IllegalArgumentException if name is not {@code "_"}

     * @throws IllegalAccessException if the lookup context does not have

     * {@linkplain Lookup#ORIGINAL original} access

     * @throws ClassCastException if the class data cannot be converted to

     * the given {@code type}

     * @throws NullPointerException if {@code caller} or {@code type} argument

     * is {@code null}

     * @see Lookup#defineHiddenClassWithClassData(byte[], Object, boolean, Lookup.ClassOption...)

     * @see MethodHandles#classDataAt(Lookup, String, Class, int)

     * @since 16

     * @jvms 5.5 Initialization

     */

     public static <T> T classData(Lookup caller, String name, Class<T> type) throws IllegalAccessException {

         Objects.requireNonNull(caller);

         Objects.requireNonNull(type);

         if (!ConstantDescs.DEFAULT_NAME.equals(name)) {

             throw new IllegalArgumentException("name must be \"_\": " + name);

         }

         if ((caller.lookupModes() & Lookup.ORIGINAL) != Lookup.ORIGINAL)  {

             throw new IllegalAccessException(caller + " does not have ORIGINAL access");

         }

         Object classdata = MethodHandleNatives.classData(caller.lookupClass());

         if (classdata == null) return null;

         try {

             return BootstrapMethodInvoker.widenAndCast(classdata, type);

         } catch (RuntimeException|Error e) {

             throw e; // let CCE and other runtime exceptions through

         } catch (Throwable e) {

             throw new InternalError(e);

         }

    }

    /**

     * Returns the element at the specified index in the

     * {@linkplain #classData(Lookup, String, Class) class data},

     * if the class data associated with the lookup class

     * of the given {@code caller} lookup object is a {@code List}.

     * If the class data is not present in this lookup class, this method

     * returns {@code null}.

     *

     * <p> A hidden class with class data can be created by calling

     * {@link Lookup#defineHiddenClassWithClassData(byte[], Object, boolean, Lookup.ClassOption...)

     * Lookup::defineHiddenClassWithClassData}.

     * This method will cause the static class initializer of the lookup

     * class of the given {@code caller} lookup object be executed if

     * it has not been initialized.

     *

     * <p> A hidden class created by {@link Lookup#defineHiddenClass(byte[], boolean, Lookup.ClassOption...)

     * Lookup::defineHiddenClass} and non-hidden classes have no class data.

     * {@code null} is returned if this method is called on the lookup object

     * on these classes.

     *

     * <p> The {@linkplain Lookup#lookupModes() lookup modes} for this lookup

     * must have {@linkplain Lookup#ORIGINAL original access}

     * in order to retrieve the class data.

     *

     * @apiNote

     * This method can be called as a bootstrap method for a dynamically computed

     * constant.  A framework can create a hidden class with class data, for

     * example that can be {@code List.of(o1, o2, o3....)} containing more than

     * one object and use this method to load one element at a specific index.

     * The class data is accessible only to the lookup object

     * created by the original caller but inaccessible to other members

     * in the same nest.  If a framework passes security sensitive objects

     * to a hidden class via class data, it is recommended to load the value

     * of class data as a dynamically computed constant instead of storing

     * the class data in private static field(s) which are accessible to other

     * nestmates.

     *

     * @param <T> the type to cast the result object to

     * @param caller the lookup context describing the class performing the

     * operation (normally stacked by the JVM)

     * @param name must be {@link java.lang.constant.ConstantDescs#DEFAULT_NAME}

     *             ({@code "_"})

     * @param type the type of the element at the given index in the class data

     * @param index index of the element in the class data

     * @return the element at the given index in the class data

     * if the class data is present; otherwise {@code null}

     * @throws IllegalArgumentException if name is not {@code "_"}

     * @throws IllegalAccessException if the lookup context does not have

     * {@linkplain Lookup#ORIGINAL original} access

     * @throws ClassCastException if the class data cannot be converted to {@code List}

     * or the element at the specified index cannot be converted to the given type

     * @throws IndexOutOfBoundsException if the index is out of range

     * @throws NullPointerException if {@code caller} or {@code type} argument is

     * {@code null}; or if unboxing operation fails because

     * the element at the given index is {@code null}

     *

     * @since 16

     * @see #classData(Lookup, String, Class)

     * @see Lookup#defineHiddenClassWithClassData(byte[], Object, boolean, Lookup.ClassOption...)

     */

    public static <T> T classDataAt(Lookup caller, String name, Class<T> type, int index)

            throws IllegalAccessException

    {

        @SuppressWarnings("unchecked")

        List<Object> classdata = (List<Object>)classData(caller, name, List.class);

        if (classdata == null) return null;

        try {

            Object element = classdata.get(index);

            return BootstrapMethodInvoker.widenAndCast(element, type);

        } catch (RuntimeException|Error e) {

            throw e; // let specified exceptions and other runtime exceptions/errors through

        } catch (Throwable e) {

            throw new InternalError(e);

        }

    }

    /**

     * Performs an unchecked "crack" of a

     * <a href="MethodHandleInfo.html#directmh">direct method handle</a>.

     * The result is as if the user had obtained a lookup object capable enough

     * to crack the target method handle, called

     * {@link java.lang.invoke.MethodHandles.Lookup#revealDirect Lookup.revealDirect}

     * on the target to obtain its symbolic reference, and then called

     * {@link java.lang.invoke.MethodHandleInfo#reflectAs MethodHandleInfo.reflectAs}

     * to resolve the symbolic reference to a member.

     * <p>

     * If there is a security manager, its {@code checkPermission} method

     * is called with a {@code ReflectPermission("suppressAccessChecks")} permission.

     * @param <T> the desired type of the result, either {@link Member} or a subtype

     * @param target a direct method handle to crack into symbolic reference components

     * @param expected a class object representing the desired result type {@code T}

     * @return a reference to the method, constructor, or field object

     * @throws    SecurityException if the caller is not privileged to call {@code setAccessible}

     * @throws    NullPointerException if either argument is {@code null}

     * @throws    IllegalArgumentException if the target is not a direct method handle

     * @throws    ClassCastException if the member is not of the expected type

     * @since 1.8

     */

    public static <T extends Member> T reflectAs(Class<T> expected, MethodHandle target) {

        @SuppressWarnings("removal")

        SecurityManager smgr = System.getSecurityManager();

        if (smgr != null)  smgr.checkPermission(ACCESS_PERMISSION);

        Lookup lookup = Lookup.IMPL_LOOKUP;  // use maximally privileged lookup

        return lookup.revealDirect(target).reflectAs(expected, lookup);

    }

    // Copied from AccessibleObject, as used by Method.setAccessible, etc.:

    private static final java.security.Permission ACCESS_PERMISSION =

        new ReflectPermission("suppressAccessChecks");

    /**

     * A <em>lookup object</em> is a factory for creating method handles,

     * when the creation requires access checking.

     * Method handles do not perform

     * access checks when they are called, but rather when they are created.

     * Therefore, method handle access

     * restrictions must be enforced when a method handle is created.

     * The caller class against which those restrictions are enforced

     * is known as the {@linkplain #lookupClass() lookup class}.

     * <p>

     * A lookup class which needs to create method handles will call

     * {@link MethodHandles#lookup() MethodHandles.lookup} to create a factory for itself.

     * When the {@code Lookup} factory object is created, the identity of the lookup class is

     * determined, and securely stored in the {@code Lookup} object.

     * The lookup class (or its delegates) may then use factory methods

     * on the {@code Lookup} object to create method handles for access-checked members.

     * This includes all methods, constructors, and fields which are allowed to the lookup class,

     * even private ones.

     *

     * <h2><a id="lookups"></a>Lookup Factory Methods</h2>

     * The factory methods on a {@code Lookup} object correspond to all major

     * use cases for methods, constructors, and fields.

     * Each method handle created by a factory method is the functional

     * equivalent of a particular <em>bytecode behavior</em>.

     * (Bytecode behaviors are described in section {@jvms 5.4.3.5} of

     * the Java Virtual Machine Specification.)

     * Here is a summary of the correspondence between these factory methods and

     * the behavior of the resulting method handles:

     * <table class="striped">

     * <caption style="display:none">lookup method behaviors</caption>

     * <thead>

     * <tr>

     *     <th scope="col"><a id="equiv"></a>lookup expression</th>

     *     <th scope="col">member</th>

     *     <th scope="col">bytecode behavior</th>

     * </tr>

     * </thead>

     * <tbody>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#findGetter lookup.findGetter(C.class,"f",FT.class)}</th>

     *     <td>{@code FT f;}</td><td>{@code (T) this.f;}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#findStaticGetter lookup.findStaticGetter(C.class,"f",FT.class)}</th>

     *     <td>{@code static}<br>{@code FT f;}</td><td>{@code (FT) C.f;}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#findSetter lookup.findSetter(C.class,"f",FT.class)}</th>

     *     <td>{@code FT f;}</td><td>{@code this.f = x;}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#findStaticSetter lookup.findStaticSetter(C.class,"f",FT.class)}</th>

     *     <td>{@code static}<br>{@code FT f;}</td><td>{@code C.f = arg;}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#findVirtual lookup.findVirtual(C.class,"m",MT)}</th>

     *     <td>{@code T m(A*);}</td><td>{@code (T) this.m(arg*);}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#findStatic lookup.findStatic(C.class,"m",MT)}</th>

     *     <td>{@code static}<br>{@code T m(A*);}</td><td>{@code (T) C.m(arg*);}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#findSpecial lookup.findSpecial(C.class,"m",MT,this.class)}</th>

     *     <td>{@code T m(A*);}</td><td>{@code (T) super.m(arg*);}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#findConstructor lookup.findConstructor(C.class,MT)}</th>

     *     <td>{@code C(A*);}</td><td>{@code new C(arg*);}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#unreflectGetter lookup.unreflectGetter(aField)}</th>

     *     <td>({@code static})?<br>{@code FT f;}</td><td>{@code (FT) aField.get(thisOrNull);}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#unreflectSetter lookup.unreflectSetter(aField)}</th>

     *     <td>({@code static})?<br>{@code FT f;}</td><td>{@code aField.set(thisOrNull, arg);}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#unreflect lookup.unreflect(aMethod)}</th>

     *     <td>({@code static})?<br>{@code T m(A*);}</td><td>{@code (T) aMethod.invoke(thisOrNull, arg*);}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#unreflectConstructor lookup.unreflectConstructor(aConstructor)}</th>

     *     <td>{@code C(A*);}</td><td>{@code (C) aConstructor.newInstance(arg*);}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#unreflectSpecial lookup.unreflectSpecial(aMethod,this.class)}</th>

     *     <td>{@code T m(A*);}</td><td>{@code (T) super.m(arg*);}</td>

     * </tr>

     * <tr>

     *     <th scope="row">{@link java.lang.invoke.MethodHandles.Lookup#findClass lookup.findClass("C")}</th>

     *     <td>{@code class C { ... }}</td><td>{@code C.class;}</td>

     * </tr>

     * </tbody>

     * </table>

     *

     * Here, the type {@code C} is the class or interface being searched for a member,

     * documented as a parameter named {@code refc} in the lookup methods.

     * The method type {@code MT} is composed from the return type {@code T}

     * and the sequence of argument types {@code A*}.

     * The constructor also has a sequence of argument types {@code A*} and

     * is deemed to return the newly-created object of type {@code C}.

     * Both {@code MT} and the field type {@code FT} are documented as a parameter named {@code type}.

     * The formal parameter {@code this} stands for the self-reference of type {@code C};

     * if it is present, it is always the leading argument to the method handle invocation.

     * (In the case of some {@code protected} members, {@code this} may be

     * restricted in type to the lookup class; see below.)

     * The name {@code arg} stands for all the other method handle arguments.

     * In the code examples for the Core Reflection API, the name {@code thisOrNull}

     * stands for a null reference if the accessed method or field is static,

     * and {@code this} otherwise.

     * The names {@code aMethod}, {@code aField}, and {@code aConstructor} stand

     * for reflective objects corresponding to the given members declared in type {@code C}.

     * <p>

     * The bytecode behavior for a {@code findClass} operation is a load of a constant class,

     * as if by {@code ldc CONSTANT_Class}.

     * The behavior is represented, not as a method handle, but directly as a {@code Class} constant.

     * <p>

     * In cases where the given member is of variable arity (i.e., a method or constructor)

     * the returned method handle will also be of {@linkplain MethodHandle#asVarargsCollector variable arity}.

     * In all other cases, the returned method handle will be of fixed arity.

     * <p style="font-size:smaller;">

     * <em>Discussion:</em>

     * The equivalence between looked-up method handles and underlying

     * class members and bytecode behaviors

     * can break down in a few ways:

     * <ul style="font-size:smaller;">

     * <li>If {@code C} is not symbolically accessible from the lookup class's loader,

     * the lookup can still succeed, even when there is no equivalent

     * Java expression or bytecoded constant.

     * <li>Likewise, if {@code T} or {@code MT}

     * is not symbolically accessible from the lookup class's loader,

     * the lookup can still succeed.

     * For example, lookups for {@code MethodHandle.invokeExact} and

     * {@code MethodHandle.invoke} will always succeed, regardless of requested type.

     * <li>If there is a security manager installed, it can forbid the lookup

     * on various grounds (<a href="MethodHandles.Lookup.html#secmgr">see below</a>).

     * By contrast, the {@code ldc} instruction on a {@code CONSTANT_MethodHandle}

     * constant is not subject to security manager checks.

     * <li>If the looked-up method has a

     * <a href="MethodHandle.html#maxarity">very large arity</a>,

     * the method handle creation may fail with an

     * {@code IllegalArgumentException}, due to the method handle type having

     * <a href="MethodHandle.html#maxarity">too many parameters.</a>

     * </ul>

     *

     * <h2><a id="access"></a>Access checking</h2>

     * Access checks are applied in the factory methods of {@code Lookup},

     * when a method handle is created.

     * This is a key difference from the Core Reflection API, since

     * {@link java.lang.reflect.Method#invoke java.lang.reflect.Method.invoke}

     * performs access checking against every caller, on every call.

     * <p>

     * All access checks start from a {@code Lookup} object, which

     * compares its recorded lookup class against all requests to

     * create method handles.

     * A single {@code Lookup} object can be used to create any number

     * of access-checked method handles, all checked against a single

     * lookup class.

     * <p>

     * A {@code Lookup} object can be shared with other trusted code,

     * such as a metaobject protocol.

     * A shared {@code Lookup} object delegates the capability

     * to create method handles on private members of the lookup class.

     * Even if privileged code uses the {@code Lookup} object,

     * the access checking is confined to the privileges of the

     * original lookup class.

     * <p>

     * A lookup can fail, because

     * the containing class is not accessible to the lookup class, or

     * because the desired class member is missing, or because the

     * desired class member is not accessible to the lookup class, or

     * because the lookup object is not trusted enough to access the member.

     * In the case of a field setter function on a {@code final} field,

     * finality enforcement is treated as a kind of access control,

     * and the lookup will fail, except in special cases of

     * {@link Lookup#unreflectSetter Lookup.unreflectSetter}.

     * In any of these cases, a {@code ReflectiveOperationException} will be

     * thrown from the attempted lookup.  The exact class will be one of

     * the following:

     * <ul>

     * <li>NoSuchMethodException &mdash; if a method is requested but does not exist

     * <li>NoSuchFieldException &mdash; if a field is requested but does not exist

     * <li>IllegalAccessException &mdash; if the member exists but an access check fails

     * </ul>

     * <p>

     * In general, the conditions under which a method handle may be

     * looked up for a method {@code M} are no more restrictive than the conditions

     * under which the lookup class could have compiled, verified, and resolved a call to {@code M}.

     * Where the JVM would raise exceptions like {@code NoSuchMethodError},

     * a method handle lookup will generally raise a corresponding

     * checked exception, such as {@code NoSuchMethodException}.

     * And the effect of invoking the method handle resulting from the lookup

     * is <a href="MethodHandles.Lookup.html#equiv">exactly equivalent</a>

     * to executing the compiled, verified, and resolved call to {@code M}.

     * The same point is true of fields and constructors.

     * <p style="font-size:smaller;">

     * <em>Discussion:</em>

     * Access checks only apply to named and reflected methods,

     * constructors, and fields.

     * Other method handle creation methods, such as

     * {@link MethodHandle#asType MethodHandle.asType},

     * do not require any access checks, and are used

     * independently of any {@code Lookup} object.

     * <p>

     * If the desired member is {@code protected}, the usual JVM rules apply,

     * including the requirement that the lookup class must either be in the

     * same package as the desired member, or must inherit that member.

     * (See the Java Virtual Machine Specification, sections {@jvms

     * 4.9.2}, {@jvms 5.4.3.5}, and {@jvms 6.4}.)

     * In addition, if the desired member is a non-static field or method

     * in a different package, the resulting method handle may only be applied

     * to objects of the lookup class or one of its subclasses.

     * This requirement is enforced by narrowing the type of the leading

     * {@code this} parameter from {@code C}

     * (which will necessarily be a superclass of the lookup class)

     * to the lookup class itself.

     * <p>

     * The JVM imposes a similar requirement on {@code invokespecial} instruction,

     * that the receiver argument must match both the resolved method <em>and</em>

     * the current class.  Again, this requirement is enforced by narrowing the

     * type of the leading parameter to the resulting method handle.

     * (See the Java Virtual Machine Specification, section {@jvms 4.10.1.9}.)

     * <p>

     * The JVM represents constructors and static initializer blocks as internal methods

     * with special names ({@code "<init>"} and {@code "<clinit>"}).

     * The internal syntax of invocation instructions allows them to refer to such internal

     * methods as if they were normal methods, but the JVM bytecode verifier rejects them.

     * A lookup of such an internal method will produce a {@code NoSuchMethodException}.

     * <p>

     * If the relationship between nested types is expressed directly through the

     * {@code NestHost} and {@code NestMembers} attributes

     * (see the Java Virtual Machine Specification, sections {@jvms

     * 4.7.28} and {@jvms 4.7.29}),

     * then the associated {@code Lookup} object provides direct access to

     * the lookup class and all of its nestmates

     * (see {@link java.lang.Class#getNestHost Class.getNestHost}).

     * Otherwise, access between nested classes is obtained by the Java compiler creating

     * a wrapper method to access a private method of another class in the same nest.

     * For example, a nested class {@code C.D}

     * can access private members within other related classes such as

     * {@code C}, {@code C.D.E}, or {@code C.B},

     * but the Java compiler may need to generate wrapper methods in

     * those related classes.  In such cases, a {@code Lookup} object on

     * {@code C.E} would be unable to access those private members.

     * A workaround for this limitation is the {@link Lookup#in Lookup.in} method,

     * which can transform a lookup on {@code C.E} into one on any of those other

     * classes, without special elevation of privilege.

     * <p>

     * The accesses permitted to a given lookup object may be limited,

     * according to its set of {@link #lookupModes lookupModes},

     * to a subset of members normally accessible to the lookup class.

     * For example, the {@link MethodHandles#publicLookup publicLookup}

     * method produces a lookup object which is only allowed to access

     * public members in public classes of exported packages.

     * The caller sensitive method {@link MethodHandles#lookup lookup}

     * produces a lookup object with full capabilities relative to

     * its caller class, to emulate all supported bytecode behaviors.

     * Also, the {@link Lookup#in Lookup.in} method may produce a lookup object

     * with fewer access modes than the original lookup object.

     *

     * <p style="font-size:smaller;">

     * <a id="privacc"></a>

     * <em>Discussion of private and module access:</em>

     * We say that a lookup has <em>private access</em>

     * if its {@linkplain #lookupModes lookup modes}

     * include the possibility of accessing {@code private} members

     * (which includes the private members of nestmates).

     * As documented in the relevant methods elsewhere,

     * only lookups with private access possess the following capabilities:

     * <ul style="font-size:smaller;">

     * <li>access private fields, methods, and constructors of the lookup class and its nestmates

     * <li>create method handles which {@link Lookup#findSpecial emulate invokespecial} instructions

     * <li>avoid <a href="MethodHandles.Lookup.html#secmgr">package access checks</a>

     *     for classes accessible to the lookup class

     * <li>create {@link Lookup#in delegated lookup objects} which have private access to other classes

     *     within the same package member

     * </ul>

     * <p style="font-size:smaller;">

     * Similarly, a lookup with module access ensures that the original lookup creator was

     * a member in the same module as the lookup class.

     * <p style="font-size:smaller;">

     * Private and module access are independently determined modes; a lookup may have

     * either or both or neither.  A lookup which possesses both access modes is said to

     * possess {@linkplain #hasFullPrivilegeAccess() full privilege access}.

     * <p style="font-size:smaller;">

     * A lookup with <em>original access</em> ensures that this lookup is created by

     * the original lookup class and the bootstrap method invoked by the VM.

     * Such a lookup with original access also has private and module access

     * which has the following additional capability:

     * <ul style="font-size:smaller;">

     * <li>create method handles which invoke <a href="MethodHandles.Lookup.html#callsens">caller sensitive</a> methods,

     *     such as {@code Class.forName}

     * <li>obtain the {@linkplain MethodHandles#classData(Lookup, String, Class)

     * class data} associated with the lookup class</li>

     * </ul>

     * <p style="font-size:smaller;">

     * Each of these permissions is a consequence of the fact that a lookup object

     * with private access can be securely traced back to an originating class,

     * whose <a href="MethodHandles.Lookup.html#equiv">bytecode behaviors</a> and Java language access permissions

     * can be reliably determined and emulated by method handles.

     *

     * <h2><a id="cross-module-lookup"></a>Cross-module lookups</h2>

     * When a lookup class in one module {@code M1} accesses a class in another module

     * {@code M2}, extra access checking is performed beyond the access mode bits.

     * A {@code Lookup} with {@link #PUBLIC} mode and a lookup class in {@code M1}

     * can access public types in {@code M2} when {@code M2} is readable to {@code M1}

     * and when the type is in a package of {@code M2} that is exported to

     * at least {@code M1}.

     * <p>

     * A {@code Lookup} on {@code C} can also <em>teleport</em> to a target class

     * via {@link #in(Class) Lookup.in} and {@link MethodHandles#privateLookupIn(Class, Lookup)

     * MethodHandles.privateLookupIn} methods.

     * Teleporting across modules will always record the original lookup class as

     * the <em>{@linkplain #previousLookupClass() previous lookup class}</em>

     * and drops {@link Lookup#MODULE MODULE} access.

     * If the target class is in the same module as the lookup class {@code C},

     * then the target class becomes the new lookup class

     * and there is no change to the previous lookup class.

     * If the target class is in a different module from {@code M1} ({@code C}'s module),

     * {@code C} becomes the new previous lookup class

     * and the target class becomes the new lookup class.

     * In that case, if there was already a previous lookup class in {@code M0},

     * and it differs from {@code M1} and {@code M2}, then the resulting lookup

     * drops all privileges.

     * For example,

     * <blockquote><pre>

     * {@code

     * Lookup lookup = MethodHandles.lookup();   // in class C

     * Lookup lookup2 = lookup.in(D.class);

     * MethodHandle mh = lookup2.findStatic(E.class, "m", MT);

     * }</pre></blockquote>

     * <p>

     * The {@link #lookup()} factory method produces a {@code Lookup} object

     * with {@code null} previous lookup class.

     * {@link Lookup#in lookup.in(D.class)} transforms the {@code lookup} on class {@code C}

     * to class {@code D} without elevation of privileges.

     * If {@code C} and {@code D} are in the same module,

     * {@code lookup2} records {@code D} as the new lookup class and keeps the

     * same previous lookup class as the original {@code lookup}, or

     * {@code null} if not present.

     * <p>

     * When a {@code Lookup} teleports from a class

     * in one nest to another nest, {@code PRIVATE} access is dropped.

     * When a {@code Lookup} teleports from a class in one package to

     * another package, {@code PACKAGE} access is dropped.

     * When a {@code Lookup} teleports from a class in one module to another module,

     * {@code MODULE} access is dropped.

     * Teleporting across modules drops the ability to access non-exported classes

     * in both the module of the new lookup class and the module of the old lookup class

     * and the resulting {@code Lookup} remains only {@code PUBLIC} access.

     * A {@code Lookup} can teleport back and forth to a class in the module of

     * the lookup class and the module of the previous class lookup.

     * Teleporting across modules can only decrease access but cannot increase it.

     * Teleporting to some third module drops all accesses.

     * <p>

     * In the above example, if {@code C} and {@code D} are in different modules,

     * {@code lookup2} records {@code D} as its lookup class and

     * {@code C} as its previous lookup class and {@code lookup2} has only

     * {@code PUBLIC} access. {@code lookup2} can teleport to other class in

     * {@code C}'s module and {@code D}'s module.

     * If class {@code E} is in a third module, {@code lookup2.in(E.class)} creates

     * a {@code Lookup} on {@code E} with no access and {@code lookup2}'s lookup

     * class {@code D} is recorded as its previous lookup class.

     * <p>

     * Teleporting across modules restricts access to the public types that

     * both the lookup class and the previous lookup class can equally access

     * (see below).

     * <p>

     * {@link MethodHandles#privateLookupIn(Class, Lookup) MethodHandles.privateLookupIn(T.class, lookup)}

     * can be used to teleport a {@code lookup} from class {@code C} to class {@code T}

     * and create a new {@code Lookup} with <a href="#privacc">private access</a>

     * if the lookup class is allowed to do <em>deep reflection</em> on {@code T}.

     * The {@code lookup} must have {@link #MODULE} and {@link #PRIVATE} access

     * to call {@code privateLookupIn}.

     * A {@code lookup} on {@code C} in module {@code M1} is allowed to do deep reflection

     * on all classes in {@code M1}.  If {@code T} is in {@code M1}, {@code privateLookupIn}

     * produces a new {@code Lookup} on {@code T} with full capabilities.

     * A {@code lookup} on {@code C} is also allowed

     * to do deep reflection on {@code T} in another module {@code M2} if

     * {@code M1} reads {@code M2} and {@code M2} {@link Module#isOpen(String,Module) opens}

     * the package containing {@code T} to at least {@code M1}.

     * {@code T} becomes the new lookup class and {@code C} becomes the new previous

     * lookup class and {@code MODULE} access is dropped from the resulting {@code Lookup}.

     * The resulting {@code Lookup} can be used to do member lookup or teleport

     * to another lookup class by calling {@link #in Lookup::in}.  But

     * it cannot be used to obtain another private {@code Lookup} by calling

     * {@link MethodHandles#privateLookupIn(Class, Lookup) privateLookupIn}

     * because it has no {@code MODULE} access.

     *

     * <h2><a id="module-access-check"></a>Cross-module access checks</h2>

     *

     * A {@code Lookup} with {@link #PUBLIC} or with {@link #UNCONDITIONAL} mode

     * allows cross-module access. The access checking is performed with respect

     * to both the lookup class and the previous lookup class if present.

     * <p>

     * A {@code Lookup} with {@link #UNCONDITIONAL} mode can access public type

     * in all modules when the type is in a package that is {@linkplain Module#isExported(String)

     * exported unconditionally}.

     * <p>

     * If a {@code Lookup} on {@code LC} in {@code M1} has no previous lookup class,

     * the lookup with {@link #PUBLIC} mode can access all public types in modules

     * that are readable to {@code M1} and the type is in a package that is exported

     * at least to {@code M1}.

     * <p>

     * If a {@code Lookup} on {@code LC} in {@code M1} has a previous lookup class

     * {@code PLC} on {@code M0}, the lookup with {@link #PUBLIC} mode can access

     * the intersection of all public types that are accessible to {@code M1}

     * with all public types that are accessible to {@code M0}. {@code M0}

     * reads {@code M1} and hence the set of accessible types includes:

     *

     * <table class="striped">

     * <caption style="display:none">

     * Public types in the following packages are accessible to the

     * lookup class and the previous lookup class.

     * </caption>

     * <thead>

     * <tr>

     * <th scope="col">Equally accessible types to {@code M0} and {@code M1}</th>

     * </tr>

     * </thead>

     * <tbody>

     * <tr>

     * <th scope="row" style="text-align:left">unconditional-exported packages from {@code M1}</th>

     * </tr>

     * <tr>

     * <th scope="row" style="text-align:left">unconditional-exported packages from {@code M0} if {@code M1} reads {@code M0}</th>

     * </tr>

     * <tr>

     * <th scope="row" style="text-align:left">unconditional-exported packages from a third module {@code M2}

     * if both {@code M0} and {@code M1} read {@code M2}</th>

     * </tr>

     * <tr>

     * <th scope="row" style="text-align:left">qualified-exported packages from {@code M1} to {@code M0}</th>

     * </tr>

     * <tr>

     * <th scope="row" style="text-align:left">qualified-exported packages from {@code M0} to {@code M1}

     * if {@code M1} reads {@code M0}</th>

     * </tr>

     * <tr>

     * <th scope="row" style="text-align:left">qualified-exported packages from a third module {@code M2} to

     * both {@code M0} and {@code M1} if both {@code M0} and {@code M1} read {@code M2}</th>

     * </tr>

     * </tbody>

     * </table>

     *

     * <h2><a id="access-modes"></a>Access modes</h2>

     *

     * The table below shows the access modes of a {@code Lookup} produced by

     * any of the following factory or transformation methods:

     * <ul>

     * <li>{@link #lookup() MethodHandles::lookup}</li>

     * <li>{@link #publicLookup() MethodHandles::publicLookup}</li>

     * <li>{@link #privateLookupIn(Class, Lookup) MethodHandles::privateLookupIn}</li>

     * <li>{@link Lookup#in Lookup::in}</li>

     * <li>{@link Lookup#dropLookupMode(int) Lookup::dropLookupMode}</li>

     * </ul>

     *

     * <table class="striped">

     * <caption style="display:none">

     * Access mode summary

     * </caption>

     * <thead>

     * <tr>

     * <th scope="col">Lookup object</th>

     * <th style="text-align:center">original</th>

     * <th style="text-align:center">protected</th>

     * <th style="text-align:center">private</th>

     * <th style="text-align:center">package</th>

     * <th style="text-align:center">module</th>

     * <th style="text-align:center">public</th>

     * </tr>

     * </thead>

     * <tbody>

     * <tr>

     * <th scope="row" style="text-align:left">{@code CL = MethodHandles.lookup()} in {@code C}</th>

     * <td style="text-align:center">ORI</td>

     * <td style="text-align:center">PRO</td>

     * <td style="text-align:center">PRI</td>

     * <td style="text-align:center">PAC</td>

     * <td style="text-align:center">MOD</td>

     * <td style="text-align:center">1R</td>

     * </tr>

     * <tr>

     * <th scope="row" style="text-align:left">{@code CL.in(C1)} same package</th>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">PAC</td>

     * <td style="text-align:center">MOD</td>

     * <td style="text-align:center">1R</td>

     * </tr>

     * <tr>

     * <th scope="row" style="text-align:left">{@code CL.in(C1)} same module</th>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">MOD</td>

     * <td style="text-align:center">1R</td>

     * </tr>

     * <tr>

     * <th scope="row" style="text-align:left">{@code CL.in(D)} different module</th>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">2R</td>

     * </tr>

     * <tr>

     * <td>{@code CL.in(D).in(C)} hop back to module</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">2R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI1 = privateLookupIn(C1,CL)}</td>

     * <td></td>

     * <td style="text-align:center">PRO</td>

     * <td style="text-align:center">PRI</td>

     * <td style="text-align:center">PAC</td>

     * <td style="text-align:center">MOD</td>

     * <td style="text-align:center">1R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI1a = privateLookupIn(C,PRI1)}</td>

     * <td></td>

     * <td style="text-align:center">PRO</td>

     * <td style="text-align:center">PRI</td>

     * <td style="text-align:center">PAC</td>

     * <td style="text-align:center">MOD</td>

     * <td style="text-align:center">1R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI1.in(C1)} same package</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">PAC</td>

     * <td style="text-align:center">MOD</td>

     * <td style="text-align:center">1R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI1.in(C1)} different package</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">MOD</td>

     * <td style="text-align:center">1R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI1.in(D)} different module</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">2R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI1.dropLookupMode(PROTECTED)}</td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">PRI</td>

     * <td style="text-align:center">PAC</td>

     * <td style="text-align:center">MOD</td>

     * <td style="text-align:center">1R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI1.dropLookupMode(PRIVATE)}</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">PAC</td>

     * <td style="text-align:center">MOD</td>

     * <td style="text-align:center">1R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI1.dropLookupMode(PACKAGE)}</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">MOD</td>

     * <td style="text-align:center">1R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI1.dropLookupMode(MODULE)}</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">1R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI1.dropLookupMode(PUBLIC)}</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">none</td>

     * <tr>

     * <td>{@code PRI2 = privateLookupIn(D,CL)}</td>

     * <td></td>

     * <td style="text-align:center">PRO</td>

     * <td style="text-align:center">PRI</td>

     * <td style="text-align:center">PAC</td>

     * <td></td>

     * <td style="text-align:center">2R</td>

     * </tr>

     * <tr>

     * <td>{@code privateLookupIn(D,PRI1)}</td>

     * <td></td>

     * <td style="text-align:center">PRO</td>

     * <td style="text-align:center">PRI</td>

     * <td style="text-align:center">PAC</td>

     * <td></td>

     * <td style="text-align:center">2R</td>

     * </tr>

     * <tr>

     * <td>{@code privateLookupIn(C,PRI2)} fails</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">IAE</td>

     * </tr>

     * <tr>

     * <td>{@code PRI2.in(D2)} same package</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">PAC</td>

     * <td></td>

     * <td style="text-align:center">2R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI2.in(D2)} different package</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">2R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI2.in(C1)} hop back to module</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">2R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI2.in(E)} hop to third module</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">none</td>

     * </tr>

     * <tr>

     * <td>{@code PRI2.dropLookupMode(PROTECTED)}</td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">PRI</td>

     * <td style="text-align:center">PAC</td>

     * <td></td>

     * <td style="text-align:center">2R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI2.dropLookupMode(PRIVATE)}</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">PAC</td>

     * <td></td>

     * <td style="text-align:center">2R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI2.dropLookupMode(PACKAGE)}</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">2R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI2.dropLookupMode(MODULE)}</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">2R</td>

     * </tr>

     * <tr>

     * <td>{@code PRI2.dropLookupMode(PUBLIC)}</td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td></td>

     * <td style="text-align:center">none</td>

     * </tr>

     * <tr>