/*

 * Copyright (c) 1994, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package java.lang;

import java.lang.annotation.Annotation;

import java.lang.constant.ClassDesc;

import java.lang.invoke.TypeDescriptor;

import java.lang.invoke.MethodHandles;

import java.lang.module.ModuleReader;

import java.lang.ref.SoftReference;

import java.io.IOException;

import java.io.InputStream;

import java.io.ObjectStreamField;

import java.lang.reflect.AnnotatedElement;

import java.lang.reflect.AnnotatedType;

import java.lang.reflect.Array;

import java.lang.reflect.Constructor;

import java.lang.reflect.Executable;

import java.lang.reflect.Field;

import java.lang.reflect.GenericArrayType;

import java.lang.reflect.GenericDeclaration;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Member;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

import java.lang.reflect.Proxy;

import java.lang.reflect.RecordComponent;

import java.lang.reflect.Type;

import java.lang.reflect.TypeVariable;

import java.lang.constant.Constable;

import java.net.URL;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collection;

import java.util.HashMap;

import java.util.HashSet;

import java.util.LinkedHashMap;

import java.util.LinkedHashSet;

import java.util.List;

import java.util.Map;

import java.util.Objects;

import java.util.Optional;

import java.util.Set;

import java.util.stream.Collectors;

import jdk.internal.loader.BootLoader;

import jdk.internal.loader.BuiltinClassLoader;

import jdk.internal.misc.Unsafe;

import jdk.internal.module.Resources;

import jdk.internal.reflect.CallerSensitive;

import jdk.internal.reflect.ConstantPool;

import jdk.internal.reflect.Reflection;

import jdk.internal.reflect.ReflectionFactory;

import jdk.internal.vm.annotation.ForceInline;

import jdk.internal.vm.annotation.IntrinsicCandidate;

import sun.invoke.util.Wrapper;

import sun.reflect.generics.factory.CoreReflectionFactory;

import sun.reflect.generics.factory.GenericsFactory;

import sun.reflect.generics.repository.ClassRepository;

import sun.reflect.generics.repository.MethodRepository;

import sun.reflect.generics.repository.ConstructorRepository;

import sun.reflect.generics.scope.ClassScope;

import sun.security.util.SecurityConstants;

import sun.reflect.annotation.*;

import sun.reflect.misc.ReflectUtil;

/**

 * Instances of the class {@code Class} represent classes and

 * interfaces in a running Java application. An enum class and a record

 * class are kinds of class; an annotation interface is a kind of

 * interface. Every array also belongs to a class that is reflected as

 * a {@code Class} object that is shared by all arrays with the same

 * element type and number of dimensions.  The primitive Java types

 * ({@code boolean}, {@code byte}, {@code char}, {@code short}, {@code

 * int}, {@code long}, {@code float}, and {@code double}), and the

 * keyword {@code void} are also represented as {@code Class} objects.

 *

 * <p> {@code Class} has no public constructor. Instead a {@code Class}

 * object is constructed automatically by the Java Virtual Machine when

 * a class is derived from the bytes of a {@code class} file through

 * the invocation of one of the following methods:

 * <ul>

 * <li> {@link ClassLoader#defineClass(String, byte[], int, int) ClassLoader::defineClass}

 * <li> {@link java.lang.invoke.MethodHandles.Lookup#defineClass(byte[])

 *      java.lang.invoke.MethodHandles.Lookup::defineClass}

 * <li> {@link java.lang.invoke.MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)

 *      java.lang.invoke.MethodHandles.Lookup::defineHiddenClass}

 * </ul>

 *

 * <p> The methods of class {@code Class} expose many characteristics of a

 * class or interface. Most characteristics are derived from the {@code class}

 * file that the class loader passed to the Java Virtual Machine or

 * from the {@code class} file passed to {@code Lookup::defineClass}

 * or {@code Lookup::defineHiddenClass}.

 * A few characteristics are determined by the class loading environment

 * at run time, such as the module returned by {@link #getModule() getModule()}.

 *

 * <p> The following example uses a {@code Class} object to print the

 * class name of an object:

 *

 * <blockquote><pre>

 *     void printClassName(Object obj) {

 *         System.out.println("The class of " + obj +

 *                            " is " + obj.getClass().getName());

 *     }

 * </pre></blockquote>

 *

 * It is also possible to get the {@code Class} object for a named

 * class or interface (or for {@code void}) using a <i>class literal</i>.

 * For example:

 *

 * <blockquote>

 *     {@code System.out.println("The name of class Foo is: "+Foo.class.getName());}

 * </blockquote>

 *

 * <p> Some methods of class {@code Class} expose whether the declaration of

 * a class or interface in Java source code was <em>enclosed</em> within

 * another declaration. Other methods describe how a class or interface

 * is situated in a <em>nest</em>. A <a id="nest">nest</a> is a set of

 * classes and interfaces, in the same run-time package, that

 * allow mutual access to their {@code private} members.

 * The classes and interfaces are known as <em>nestmates</em>.

 * One nestmate acts as the

 * <em>nest host</em>, and enumerates the other nestmates which

 * belong to the nest; each of them in turn records it as the nest host.

 * The classes and interfaces which belong to a nest, including its host, are

 * determined when

 * {@code class} files are generated, for example, a Java compiler

 * will typically record a top-level class as the host of a nest where the

 * other members are the classes and interfaces whose declarations are

 * enclosed within the top-level class declaration.

 *

 * <p> A class or interface created by the invocation of

 * {@link java.lang.invoke.MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)

 * Lookup::defineHiddenClass} is a {@linkplain Class#isHidden() <em>hidden</em>}

 * class or interface.

 * All kinds of class, including enum classes and record classes, may be

 * hidden classes; all kinds of interface, including annotation interfaces,

 * may be hidden interfaces.

 *

 * The {@linkplain #getName() name of a hidden class or interface} is

 * not a <a href="ClassLoader.html#binary-name">binary name</a>,

 * which means the following:

 * <ul>

 * <li>A hidden class or interface cannot be referenced by the constant pools

 *     of other classes and interfaces.

 * <li>A hidden class or interface cannot be described in

 *     {@linkplain java.lang.constant.ConstantDesc <em>nominal form</em>} by

 *     {@link #describeConstable() Class::describeConstable},

 *     {@link ClassDesc#of(String) ClassDesc::of}, or

 *     {@link ClassDesc#ofDescriptor(String) ClassDesc::ofDescriptor}.

 * <li>A hidden class or interface cannot be discovered by {@link #forName Class::forName}

 *     or {@link ClassLoader#loadClass(String, boolean) ClassLoader::loadClass}.

 * </ul>

 *

 * A hidden class or interface is never an array class, but may be

 * the element type of an array. In all other respects, the fact that

 * a class or interface is hidden has no bearing on the characteristics

 * exposed by the methods of class {@code Class}.

 *

 * @param <T> the type of the class modeled by this {@code Class}

 * object.  For example, the type of {@code String.class} is {@code

 * Class<String>}.  Use {@code Class<?>} if the class being modeled is

 * unknown.

 *

 * @see     java.lang.ClassLoader#defineClass(byte[], int, int)

 * @since   1.0

 * @jls 15.8.2 Class Literals

 */

public final class Class<T> implements java.io.Serializable,

                              GenericDeclaration,

                              Type,

                              AnnotatedElement,

                              TypeDescriptor.OfField<Class<?>>,

                              Constable {

    private static final int ANNOTATION= 0x00002000;

    private static final int ENUM      = 0x00004000;

    private static final int SYNTHETIC = 0x00001000;

    private static native void registerNatives();

    static {

        registerNatives();

    }

    /*

     * Private constructor. Only the Java Virtual Machine creates Class objects.

     * This constructor is not used and prevents the default constructor being

     * generated.

     */

    private Class(ClassLoader loader, Class<?> arrayComponentType) {

        // Initialize final field for classLoader.  The initialization value of non-null

        // prevents future JIT optimizations from assuming this final field is null.

        classLoader = loader;

        componentType = arrayComponentType;

    }

    /**

     * Converts the object to a string. The string representation is the

     * string "class" or "interface", followed by a space, and then by the

     * name of the class in the format returned by {@code getName}.

     * If this {@code Class} object represents a primitive type,

     * this method returns the name of the primitive type.  If

     * this {@code Class} object represents void this method returns

     * "void". If this {@code Class} object represents an array type,

     * this method returns "class " followed by {@code getName}.

     *

     * @return a string representation of this {@code Class} object.

     */

    public String toString() {

        return (isInterface() ? "interface " : (isPrimitive() ? "" : "class "))

            + getName();

    }

    /**

     * Returns a string describing this {@code Class}, including

     * information about modifiers and type parameters.

     *

     * The string is formatted as a list of type modifiers, if any,

     * followed by the kind of type (empty string for primitive types

     * and {@code class}, {@code enum}, {@code interface},

     * {@code @interface}, or {@code record} as appropriate), followed

     * by the type's name, followed by an angle-bracketed

     * comma-separated list of the type's type parameters, if any,

     * including informative bounds on the type parameters, if any.

     *

     * A space is used to separate modifiers from one another and to

     * separate any modifiers from the kind of type. The modifiers

     * occur in canonical order. If there are no type parameters, the

     * type parameter list is elided.

     *

     * For an array type, the string starts with the type name,

     * followed by an angle-bracketed comma-separated list of the

     * type's type parameters, if any, followed by a sequence of

     * {@code []} characters, one set of brackets per dimension of

     * the array.

     *

     * <p>Note that since information about the runtime representation

     * of a type is being generated, modifiers not present on the

     * originating source code or illegal on the originating source

     * code may be present.

     *

     * @return a string describing this {@code Class}, including

     * information about modifiers and type parameters

     *

     * @since 1.8

     */

    public String toGenericString() {

        if (isPrimitive()) {

            return toString();

        } else {

            StringBuilder sb = new StringBuilder();

            Class<?> component = this;

            int arrayDepth = 0;

            if (isArray()) {

                do {

                    arrayDepth++;

                    component = component.getComponentType();

                } while (component.isArray());

                sb.append(component.getName());

            } else {

                // Class modifiers are a superset of interface modifiers

                int modifiers = getModifiers() & Modifier.classModifiers();

                if (modifiers != 0) {

                    sb.append(Modifier.toString(modifiers));

                    sb.append(' ');

                }

                if (isAnnotation()) {

                    sb.append('@');

                }

                if (isInterface()) { // Note: all annotation interfaces are interfaces

                    sb.append("interface");

                } else {

                    if (isEnum())

                        sb.append("enum");

                    else if (isRecord())

                        sb.append("record");

                    else

                        sb.append("class");

                }

                sb.append(' ');

                sb.append(getName());

            }

            TypeVariable<?>[] typeparms = component.getTypeParameters();

            if (typeparms.length > 0) {

                sb.append(Arrays.stream(typeparms)

                          .map(Class::typeVarBounds)

                          .collect(Collectors.joining(",", "<", ">")));

            }

            if (arrayDepth > 0) sb.append("[]".repeat(arrayDepth));

            return sb.toString();

        }

    }

    static String typeVarBounds(TypeVariable<?> typeVar) {

        Type[] bounds = typeVar.getBounds();

        if (bounds.length == 1 && bounds[0].equals(Object.class)) {

            return typeVar.getName();

        } else {

            return typeVar.getName() + " extends " +

                Arrays.stream(bounds)

                .map(Type::getTypeName)

                .collect(Collectors.joining(" & "));

        }

    }

    /**

     * Returns the {@code Class} object associated with the class or

     * interface with the given string name.  Invoking this method is

     * equivalent to:

     *

     * <blockquote>

     *  {@code Class.forName(className, true, currentLoader)}

     * </blockquote>

     *

     * where {@code currentLoader} denotes the defining class loader of

     * the current class.

     *

     * <p> For example, the following code fragment returns the

     * runtime {@code Class} descriptor for the class named

     * {@code java.lang.Thread}:

     *

     * <blockquote>

     *   {@code Class t = Class.forName("java.lang.Thread")}

     * </blockquote>

     * <p>

     * A call to {@code forName("X")} causes the class named

     * {@code X} to be initialized.

     *

     * @param      className   the fully qualified name of the desired class.

     * @return     the {@code Class} object for the class with the

     *             specified name.

     * @throws    LinkageError if the linkage fails

     * @throws    ExceptionInInitializerError if the initialization provoked

     *            by this method fails

     * @throws    ClassNotFoundException if the class cannot be located

     *

     * @jls 12.2 Loading of Classes and Interfaces

     * @jls 12.3 Linking of Classes and Interfaces

     * @jls 12.4 Initialization of Classes and Interfaces

     */

    @CallerSensitive

    public static Class<?> forName(String className)

                throws ClassNotFoundException {

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

        return forName0(className, true, ClassLoader.getClassLoader(caller), caller);

    }

    /**

     * Returns the {@code Class} object associated with the class or

     * interface with the given string name, using the given class loader.

     * Given the fully qualified name for a class or interface (in the same

     * format returned by {@code getName}) this method attempts to

     * locate and load the class or interface.  The specified class

     * loader is used to load the class or interface.  If the parameter

     * {@code loader} is null, the class is loaded through the bootstrap

     * class loader.  The class is initialized only if the

     * {@code initialize} parameter is {@code true} and if it has

     * not been initialized earlier.

     *

     * <p> If {@code name} denotes a primitive type or void, an attempt

     * will be made to locate a user-defined class in the unnamed package whose

     * name is {@code name}. Therefore, this method cannot be used to

     * obtain any of the {@code Class} objects representing primitive

     * types or void.

     *

     * <p> If {@code name} denotes an array class, the component type of

     * the array class is loaded but not initialized.

     *

     * <p> For example, in an instance method the expression:

     *

     * <blockquote>

     *  {@code Class.forName("Foo")}

     * </blockquote>

     *

     * is equivalent to:

     *

     * <blockquote>

     *  {@code Class.forName("Foo", true, this.getClass().getClassLoader())}

     * </blockquote>

     *

     * Note that this method throws errors related to loading, linking

     * or initializing as specified in Sections {@jls 12.2}, {@jls

     * 12.3}, and {@jls 12.4} of <cite>The Java Language

     * Specification</cite>.

     * Note that this method does not check whether the requested class

     * is accessible to its caller.

     *

     * @param name       fully qualified name of the desired class

     * @param initialize if {@code true} the class will be initialized

     *                   (which implies linking). See Section {@jls

     *                   12.4} of <cite>The Java Language

     *                   Specification</cite>.

     * @param loader     class loader from which the class must be loaded

     * @return           class object representing the desired class

     *

     * @throws    LinkageError if the linkage fails

     * @throws    ExceptionInInitializerError if the initialization provoked

     *            by this method fails

     * @throws    ClassNotFoundException if the class cannot be located by

     *            the specified class loader

     * @throws    SecurityException

     *            if a security manager is present, and the {@code loader} is

     *            {@code null}, and the caller's class loader is not

     *            {@code null}, and the caller does not have the

     *            {@link RuntimePermission}{@code ("getClassLoader")}

     *

     * @see       java.lang.Class#forName(String)

     * @see       java.lang.ClassLoader

     *

     * @jls 12.2 Loading of Classes and Interfaces

     * @jls 12.3 Linking of Classes and Interfaces

     * @jls 12.4 Initialization of Classes and Interfaces

     * @since     1.2

     */

    @CallerSensitive

    public static Class<?> forName(String name, boolean initialize,

                                   ClassLoader loader)

        throws ClassNotFoundException

    {

        Class<?> caller = null;

        @SuppressWarnings("removal")

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            // Reflective call to get caller class is only needed if a security manager

            // is present.  Avoid the overhead of making this call otherwise.

            caller = Reflection.getCallerClass();

            if (loader == null) {

                ClassLoader ccl = ClassLoader.getClassLoader(caller);

                if (ccl != null) {

                    sm.checkPermission(

                        SecurityConstants.GET_CLASSLOADER_PERMISSION);

                }

            }

        }

        return forName0(name, initialize, loader, caller);

    }

    /** Called after security check for system loader access checks have been made. */

    private static native Class<?> forName0(String name, boolean initialize,

                                            ClassLoader loader,

                                            Class<?> caller)

        throws ClassNotFoundException;

    /**

     * Returns the {@code Class} with the given <a href="ClassLoader.html#binary-name">

     * binary name</a> in the given module.

     *

     * <p> This method attempts to locate and load the class or interface.

     * It does not link the class, and does not run the class initializer.

     * If the class is not found, this method returns {@code null}. </p>

     *

     * <p> If the class loader of the given module defines other modules and

     * the given name is a class defined in a different module, this method

     * returns {@code null} after the class is loaded. </p>

     *

     * <p> This method does not check whether the requested class is

     * accessible to its caller. </p>

     *

     * @apiNote

     * This method returns {@code null} on failure rather than

     * throwing a {@link ClassNotFoundException}, as is done by

     * the {@link #forName(String, boolean, ClassLoader)} method.

     * The security check is a stack-based permission check if the caller

     * loads a class in another module.

     *

     * @param  module   A module

     * @param  name     The <a href="ClassLoader.html#binary-name">binary name</a>

     *                  of the class

     * @return {@code Class} object of the given name defined in the given module;

     *         {@code null} if not found.

     *

     * @throws NullPointerException if the given module or name is {@code null}

     *

     * @throws LinkageError if the linkage fails

     *

     * @throws SecurityException

     *         <ul>

     *         <li> if the caller is not the specified module and

     *         {@code RuntimePermission("getClassLoader")} permission is denied; or</li>

     *         <li> access to the module content is denied. For example,

     *         permission check will be performed when a class loader calls

     *         {@link ModuleReader#open(String)} to read the bytes of a class file

     *         in a module.</li>

     *         </ul>

     *

     * @jls 12.2 Loading of Classes and Interfaces

     * @jls 12.3 Linking of Classes and Interfaces

     * @since 9

     */

    @SuppressWarnings("removal")

    @CallerSensitive

    public static Class<?> forName(Module module, String name) {

        Objects.requireNonNull(module);

        Objects.requireNonNull(name);

        ClassLoader cl;

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

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

            if (caller != null && caller.getModule() != module) {

                // if caller is null, Class.forName is the last java frame on the stack.

                // java.base has all permissions

                sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);

            }

            PrivilegedAction<ClassLoader> pa = module::getClassLoader;

            cl = AccessController.doPrivileged(pa);

        } else {

            cl = module.getClassLoader();

        }

        if (cl != null) {

            return cl.loadClass(module, name);

        } else {

            return BootLoader.loadClass(module, name);

        }

    }

    /**

     * Creates a new instance of the class represented by this {@code Class}

     * object.  The class is instantiated as if by a {@code new}

     * expression with an empty argument list.  The class is initialized if it

     * has not already been initialized.

     *

     * @deprecated This method propagates any exception thrown by the

     * nullary constructor, including a checked exception.  Use of

     * this method effectively bypasses the compile-time exception

     * checking that would otherwise be performed by the compiler.

     * The {@link

     * java.lang.reflect.Constructor#newInstance(java.lang.Object...)

     * Constructor.newInstance} method avoids this problem by wrapping

     * any exception thrown by the constructor in a (checked) {@link

     * java.lang.reflect.InvocationTargetException}.

     *

     * <p>The call

     *

     * <pre>{@code

     * clazz.newInstance()

     * }</pre>

     *

     * can be replaced by

     *

     * <pre>{@code

     * clazz.getDeclaredConstructor().newInstance()

     * }</pre>

     *

     * The latter sequence of calls is inferred to be able to throw

     * the additional exception types {@link

     * InvocationTargetException} and {@link

     * NoSuchMethodException}. Both of these exception types are

     * subclasses of {@link ReflectiveOperationException}.

     *

     * @return  a newly allocated instance of the class represented by this

     *          object.

     * @throws  IllegalAccessException  if the class or its nullary

     *          constructor is not accessible.

     * @throws  InstantiationException

     *          if this {@code Class} represents an abstract class,

     *          an interface, an array class, a primitive type, or void;

     *          or if the class has no nullary constructor;

     *          or if the instantiation fails for some other reason.

     * @throws  ExceptionInInitializerError if the initialization

     *          provoked by this method fails.

     * @throws  SecurityException

     *          If a security manager, <i>s</i>, is present and

     *          the caller's class loader is not the same as or an

     *          ancestor of the class loader for the current class and

     *          invocation of {@link SecurityManager#checkPackageAccess

     *          s.checkPackageAccess()} denies access to the package

     *          of this class.

     */

    @SuppressWarnings("removal")

    @CallerSensitive

    @Deprecated(since="9")

    public T newInstance()

        throws InstantiationException, IllegalAccessException

    {

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), false);

        }

        // Constructor lookup

        Constructor<T> tmpConstructor = cachedConstructor;

        if (tmpConstructor == null) {

            if (this == Class.class) {

                throw new IllegalAccessException(

                    "Can not call newInstance() on the Class for java.lang.Class"

                );

            }

            try {

                Class<?>[] empty = {};

                final Constructor<T> c = getReflectionFactory().copyConstructor(

                    getConstructor0(empty, Member.DECLARED));

                // Disable accessibility checks on the constructor

                // access check is done with the true caller

                java.security.AccessController.doPrivileged(

                    new java.security.PrivilegedAction<>() {

                        public Void run() {

                                c.setAccessible(true);

                                return null;

                            }

                        });

                cachedConstructor = tmpConstructor = c;

            } catch (NoSuchMethodException e) {

                throw (InstantiationException)

                    new InstantiationException(getName()).initCause(e);

            }

        }

        try {

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

            return getReflectionFactory().newInstance(tmpConstructor, null, caller);

        } catch (InvocationTargetException e) {

            Unsafe.getUnsafe().throwException(e.getTargetException());

            // Not reached

            return null;

        }

    }

    private transient volatile Constructor<T> cachedConstructor;

    /**

     * Determines if the specified {@code Object} is assignment-compatible

     * with the object represented by this {@code Class}.  This method is

     * the dynamic equivalent of the Java language {@code instanceof}

     * operator. The method returns {@code true} if the specified

     * {@code Object} argument is non-null and can be cast to the

     * reference type represented by this {@code Class} object without

     * raising a {@code ClassCastException.} It returns {@code false}

     * otherwise.

     *

     * <p> Specifically, if this {@code Class} object represents a

     * declared class, this method returns {@code true} if the specified

     * {@code Object} argument is an instance of the represented class (or

     * of any of its subclasses); it returns {@code false} otherwise. If

     * this {@code Class} object represents an array class, this method

     * returns {@code true} if the specified {@code Object} argument

     * can be converted to an object of the array class by an identity

     * conversion or by a widening reference conversion; it returns

     * {@code false} otherwise. If this {@code Class} object

     * represents an interface, this method returns {@code true} if the

     * class or any superclass of the specified {@code Object} argument

     * implements this interface; it returns {@code false} otherwise. If

     * this {@code Class} object represents a primitive type, this method

     * returns {@code false}.

     *

     * @param   obj the object to check

     * @return  true if {@code obj} is an instance of this class

     *

     * @since 1.1

     */

    @IntrinsicCandidate

    public native boolean isInstance(Object obj);

    /**

     * Determines if the class or interface represented by this

     * {@code Class} object is either the same as, or is a superclass or

     * superinterface of, the class or interface represented by the specified

     * {@code Class} parameter. It returns {@code true} if so;

     * otherwise it returns {@code false}. If this {@code Class}

     * object represents a primitive type, this method returns

     * {@code true} if the specified {@code Class} parameter is

     * exactly this {@code Class} object; otherwise it returns

     * {@code false}.

     *

     * <p> Specifically, this method tests whether the type represented by the

     * specified {@code Class} parameter can be converted to the type

     * represented by this {@code Class} object via an identity conversion

     * or via a widening reference conversion. See <cite>The Java Language

     * Specification</cite>, sections {@jls 5.1.1} and {@jls 5.1.4},

     * for details.

     *

     * @param     cls the {@code Class} object to be checked

     * @return    the {@code boolean} value indicating whether objects of the

     *            type {@code cls} can be assigned to objects of this class

     * @throws    NullPointerException if the specified Class parameter is

     *            null.

     * @since     1.1

     */

    @IntrinsicCandidate

    public native boolean isAssignableFrom(Class<?> cls);

    /**

     * Determines if this {@code Class} object represents an

     * interface type.

     *

     * @return  {@code true} if this {@code Class} object represents an interface;

     *          {@code false} otherwise.

     */

    @IntrinsicCandidate

    public native boolean isInterface();

    /**

     * Determines if this {@code Class} object represents an array class.

     *

     * @return  {@code true} if this {@code Class} object represents an array class;

     *          {@code false} otherwise.

     * @since   1.1

     */

    @IntrinsicCandidate

    public native boolean isArray();

    /**

     * Determines if the specified {@code Class} object represents a

     * primitive type.

     *

     * <p> There are nine predefined {@code Class} objects to represent

     * the eight primitive types and void.  These are created by the Java

     * Virtual Machine, and have the same names as the primitive types that

     * they represent, namely {@code boolean}, {@code byte},

     * {@code char}, {@code short}, {@code int},

     * {@code long}, {@code float}, and {@code double}.

     *

     * <p> These objects may only be accessed via the following public static

     * final variables, and are the only {@code Class} objects for which

     * this method returns {@code true}.

     *

     * @return true if and only if this class represents a primitive type

     *

     * @see     java.lang.Boolean#TYPE

     * @see     java.lang.Character#TYPE

     * @see     java.lang.Byte#TYPE

     * @see     java.lang.Short#TYPE

     * @see     java.lang.Integer#TYPE

     * @see     java.lang.Long#TYPE

     * @see     java.lang.Float#TYPE

     * @see     java.lang.Double#TYPE

     * @see     java.lang.Void#TYPE

     * @since 1.1

     */

    @IntrinsicCandidate

    public native boolean isPrimitive();

    /**

     * Returns true if this {@code Class} object represents an annotation

     * interface.  Note that if this method returns true, {@link #isInterface()}

     * would also return true, as all annotation interfaces are also interfaces.

     *

     * @return {@code true} if this {@code Class} object represents an annotation

     *      interface; {@code false} otherwise

     * @since 1.5

     */

    public boolean isAnnotation() {

        return (getModifiers() & ANNOTATION) != 0;

    }

    /**

     *{@return {@code true} if and only if this class has the synthetic modifier

     * bit set}

     *

     * @jls 13.1 The Form of a Binary

     * @jvms 4.1 The {@code ClassFile} Structure

     * @see <a

     * href="{@docRoot}/java.base/java/lang/reflect/package-summary.html#LanguageJvmModel">Java

     * programming language and JVM modeling in core reflection</a>

     * @since 1.5

     */

    public boolean isSynthetic() {

        return (getModifiers() & SYNTHETIC) != 0;

    }

    /**

     * Returns the  name of the entity (class, interface, array class,

     * primitive type, or void) represented by this {@code Class} object.

     *

     * <p> If this {@code Class} object represents a class or interface,

     * not an array class, then:

     * <ul>

     * <li> If the class or interface is not {@linkplain #isHidden() hidden},

     *      then the <a href="ClassLoader.html#binary-name">binary name</a>

     *      of the class or interface is returned.

     * <li> If the class or interface is hidden, then the result is a string

     *      of the form: {@code N + '/' + <suffix>}

     *      where {@code N} is the <a href="ClassLoader.html#binary-name">binary name</a>

     *      indicated by the {@code class} file passed to

     *      {@link java.lang.invoke.MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)

     *      Lookup::defineHiddenClass}, and {@code <suffix>} is an unqualified name.

     * </ul>

     *

     * <p> If this {@code Class} object represents an array class, then

     * the result is a string consisting of one or more '{@code [}' characters

     * representing the depth of the array nesting, followed by the element

     * type as encoded using the following table:

     *

     * <blockquote><table class="striped">

     * <caption style="display:none">Element types and encodings</caption>

     * <thead>

     * <tr><th scope="col"> Element Type <th scope="col"> Encoding

     * </thead>

     * <tbody style="text-align:left">

     * <tr><th scope="row"> {@code boolean} <td style="text-align:center"> {@code Z}

     * <tr><th scope="row"> {@code byte}    <td style="text-align:center"> {@code B}

     * <tr><th scope="row"> {@code char}    <td style="text-align:center"> {@code C}

     * <tr><th scope="row"> class or interface with <a href="ClassLoader.html#binary-name">binary name</a> <i>N</i>

     *                                      <td style="text-align:center"> {@code L}<em>N</em>{@code ;}

     * <tr><th scope="row"> {@code double}  <td style="text-align:center"> {@code D}

     * <tr><th scope="row"> {@code float}   <td style="text-align:center"> {@code F}

     * <tr><th scope="row"> {@code int}     <td style="text-align:center"> {@code I}

     * <tr><th scope="row"> {@code long}    <td style="text-align:center"> {@code J}

     * <tr><th scope="row"> {@code short}   <td style="text-align:center"> {@code S}

     * </tbody>

     * </table></blockquote>

     *

     * <p> If this {@code Class} object represents a primitive type or {@code void},

     * then the result is a string with the same spelling as the Java language

     * keyword which corresponds to the primitive type or {@code void}.

     *

     * <p> Examples:

     * <blockquote><pre>

     * String.class.getName()

     *     returns "java.lang.String"

     * byte.class.getName()

     *     returns "byte"

     * (new Object[3]).getClass().getName()

     *     returns "[Ljava.lang.Object;"

     * (new int[3][4][5][6][7][8][9]).getClass().getName()

     *     returns "[[[[[[[I"

     * </pre></blockquote>

     *

     * @return  the name of the class, interface, or other entity

     *          represented by this {@code Class} object.

     * @jls 13.1 The Form of a Binary

     */

    public String getName() {

        String name = this.name;

        return name != null ? name : initClassName();

    }

    // Cache the name to reduce the number of calls into the VM.

    // This field would be set by VM itself during initClassName call.

    private transient String name;

    private native String initClassName();

    /**

     * Returns the class loader for the class.  Some implementations may use

     * null to represent the bootstrap class loader. This method will return

     * null in such implementations if this class was loaded by the bootstrap

     * class loader.

     *

     * <p>If this {@code Class} object

     * represents a primitive type or void, null is returned.

     *

     * @return  the class loader that loaded the class or interface

     *          represented by this {@code Class} object.

     * @throws  SecurityException

     *          if a security manager is present, and the caller's class loader

     *          is not {@code null} and is not the same as or an ancestor of the

     *          class loader for the class whose class loader is requested,

     *          and the caller does not have the

     *          {@link RuntimePermission}{@code ("getClassLoader")}

     * @see java.lang.ClassLoader

     * @see SecurityManager#checkPermission

     * @see java.lang.RuntimePermission

     */

    @CallerSensitive

    @ForceInline // to ensure Reflection.getCallerClass optimization

    public ClassLoader getClassLoader() {

        ClassLoader cl = getClassLoader0();

        if (cl == null)

            return null;

        @SuppressWarnings("removal")

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            ClassLoader.checkClassLoaderPermission(cl, Reflection.getCallerClass());

        }

        return cl;

    }

    // Package-private to allow ClassLoader access

    ClassLoader getClassLoader0() { return classLoader; }

    /**

     * Returns the module that this class or interface is a member of.

     *

     * If this class represents an array type then this method returns the

     * {@code Module} for the element type. If this class represents a

     * primitive type or void, then the {@code Module} object for the

     * {@code java.base} module is returned.

     *

     * If this class is in an unnamed module then the {@linkplain

     * ClassLoader#getUnnamedModule() unnamed} {@code Module} of the class

     * loader for this class is returned.

     *

     * @return the module that this class or interface is a member of

     *

     * @since 9

     */

    public Module getModule() {

        return module;

    }

    // set by VM

    private transient Module module;

    // Initialized in JVM not by private constructor

    // This field is filtered from reflection access, i.e. getDeclaredField

    // will throw NoSuchFieldException

    private final ClassLoader classLoader;

    // Set by VM

    private transient Object classData;

    // package-private

    Object getClassData() {

        return classData;

    }

    /**

     * Returns an array of {@code TypeVariable} objects that represent the

     * type variables declared by the generic declaration represented by this

     * {@code GenericDeclaration} object, in declaration order.  Returns an

     * array of length 0 if the underlying generic declaration declares no type

     * variables.

     *

     * @return an array of {@code TypeVariable} objects that represent

     *     the type variables declared by this generic declaration

     * @throws java.lang.reflect.GenericSignatureFormatError if the generic

     *     signature of this generic declaration does not conform to

     *     the format specified in section {@jvms 4.7.9} of

     *     <cite>The Java Virtual Machine Specification</cite>

     * @since 1.5

     */

    @SuppressWarnings("unchecked")

    public TypeVariable<Class<T>>[] getTypeParameters() {

        ClassRepository info = getGenericInfo();

        if (info != null)

            return (TypeVariable<Class<T>>[])info.getTypeParameters();

        else

            return (TypeVariable<Class<T>>[])new TypeVariable<?>[0];

    }

    /**

     * Returns the {@code Class} representing the direct superclass of the

     * entity (class, interface, primitive type or void) represented by

     * this {@code Class}.  If this {@code Class} represents either the

     * {@code Object} class, an interface, a primitive type, or void, then

     * null is returned.  If this {@code Class} object represents an array class

     * then the {@code Class} object representing the {@code Object} class is

     * returned.

     *

     * @return the direct superclass of the class represented by this {@code Class} object

     */

    @IntrinsicCandidate

    public native Class<? super T> getSuperclass();

    /**

     * Returns the {@code Type} representing the direct superclass of

     * the entity (class, interface, primitive type or void) represented by

     * this {@code Class} object.

     *

     * <p>If the superclass is a parameterized type, the {@code Type}

     * object returned must accurately reflect the actual type

     * arguments used in the source code. The parameterized type

     * representing the superclass is created if it had not been

     * created before. See the declaration of {@link

     * java.lang.reflect.ParameterizedType ParameterizedType} for the

     * semantics of the creation process for parameterized types.  If

     * this {@code Class} object represents either the {@code Object}

     * class, an interface, a primitive type, or void, then null is

     * returned.  If this {@code Class} object represents an array class

     * then the {@code Class} object representing the {@code Object} class is

     * returned.

     *

     * @throws java.lang.reflect.GenericSignatureFormatError if the generic

     *     class signature does not conform to the format specified in

     *     section {@jvms 4.7.9} of <cite>The Java Virtual

     *     Machine Specification</cite>

     * @throws TypeNotPresentException if the generic superclass

     *     refers to a non-existent type declaration

     * @throws java.lang.reflect.MalformedParameterizedTypeException if the

     *     generic superclass refers to a parameterized type that cannot be

     *     instantiated  for any reason

     * @return the direct superclass of the class represented by this {@code Class} object

     * @since 1.5

     */

    public Type getGenericSuperclass() {

        ClassRepository info = getGenericInfo();

        if (info == null) {

            return getSuperclass();

        }

        // Historical irregularity:

        // Generic signature marks interfaces with superclass = Object

        // but this API returns null for interfaces

        if (isInterface()) {

            return null;

        }

        return info.getSuperclass();

    }

    /**

     * Gets the package of this class.

     *

     * <p>If this class represents an array type, a primitive type or void,

     * this method returns {@code null}.

     *

     * @return the package of this class.

     * @revised 9

     */

    public Package getPackage() {

        if (isPrimitive() || isArray()) {

            return null;

        }

        ClassLoader cl = getClassLoader0();

        return cl != null ? cl.definePackage(this)

                          : BootLoader.definePackage(this);

    }

    /**

     * Returns the fully qualified package name.

     *

     * <p> If this class is a top level class, then this method returns the fully

     * qualified name of the package that the class is a member of, or the

     * empty string if the class is in an unnamed package.

     *

     * <p> If this class is a member class, then this method is equivalent to

     * invoking {@code getPackageName()} on the {@linkplain #getEnclosingClass

     * enclosing class}.

     *

     * <p> If this class is a {@linkplain #isLocalClass local class} or an {@linkplain

     * #isAnonymousClass() anonymous class}, then this method is equivalent to

     * invoking {@code getPackageName()} on the {@linkplain #getDeclaringClass

     * declaring class} of the {@linkplain #getEnclosingMethod enclosing method} or

     * {@linkplain #getEnclosingConstructor enclosing constructor}.

     *

     * <p> If this class represents an array type then this method returns the

     * package name of the element type. If this class represents a primitive

     * type or void then the package name "{@code java.lang}" is returned.

     *

     * @return the fully qualified package name

     *

     * @since 9

     * @jls 6.7 Fully Qualified Names

     */

    public String getPackageName() {

        String pn = this.packageName;

        if (pn == null) {

            Class<?> c = isArray() ? elementType() : this;

            if (c.isPrimitive()) {

                pn = "java.lang";

            } else {

                String cn = c.getName();

                int dot = cn.lastIndexOf('.');

                pn = (dot != -1) ? cn.substring(0, dot).intern() : "";

            }

            this.packageName = pn;

        }

        return pn;

    }

    // cached package name

    private transient String packageName;

    /**

     * Returns the interfaces directly implemented by the class or interface

     * represented by this {@code Class} object.

     *

     * <p>If this {@code Class} object represents a class, the return value is an array

     * containing objects representing all interfaces directly implemented by

     * the class.  The order of the interface objects in the array corresponds

     * to the order of the interface names in the {@code implements} clause of

     * the declaration of the class represented by this {@code Class} object.  For example,

     * given the declaration:

     * <blockquote>

     * {@code class Shimmer implements FloorWax, DessertTopping { ... }}

     * </blockquote>

     * suppose the value of {@code s} is an instance of

     * {@code Shimmer}; the value of the expression:

     * <blockquote>

     * {@code s.getClass().getInterfaces()[0]}

     * </blockquote>

     * is the {@code Class} object that represents interface

     * {@code FloorWax}; and the value of:

     * <blockquote>

     * {@code s.getClass().getInterfaces()[1]}

     * </blockquote>

     * is the {@code Class} object that represents interface

     * {@code DessertTopping}.

     *

     * <p>If this {@code Class} object represents an interface, the array contains objects

     * representing all interfaces directly extended by the interface.  The

     * order of the interface objects in the array corresponds to the order of

     * the interface names in the {@code extends} clause of the declaration of

     * the interface represented by this {@code Class} object.

     *

     * <p>If this {@code Class} object represents a class or interface that implements no

     * interfaces, the method returns an array of length 0.

     *

     * <p>If this {@code Class} object represents a primitive type or void, the method

     * returns an array of length 0.

     *

     * <p>If this {@code Class} object represents an array type, the

     * interfaces {@code Cloneable} and {@code java.io.Serializable} are

     * returned in that order.

     *

     * @return an array of interfaces directly implemented by this class

     */

    public Class<?>[] getInterfaces() {

        // defensively copy before handing over to user code

        return getInterfaces(true);

    }

    private Class<?>[] getInterfaces(boolean cloneArray) {

        ReflectionData<T> rd = reflectionData();

        if (rd == null) {

            // no cloning required

            return getInterfaces0();

        } else {

            Class<?>[] interfaces = rd.interfaces;

            if (interfaces == null) {

                interfaces = getInterfaces0();

                rd.interfaces = interfaces;

            }

            // defensively copy if requested

            return cloneArray ? interfaces.clone() : interfaces;

        }

    }

    private native Class<?>[] getInterfaces0();

    /**

     * Returns the {@code Type}s representing the interfaces

     * directly implemented by the class or interface represented by

     * this {@code Class} object.

     *

     * <p>If a superinterface is a parameterized type, the

     * {@code Type} object returned for it must accurately reflect

     * the actual type arguments used in the source code. The

     * parameterized type representing each superinterface is created

     * if it had not been created before. See the declaration of

     * {@link java.lang.reflect.ParameterizedType ParameterizedType}

     * for the semantics of the creation process for parameterized

     * types.

     *

     * <p>If this {@code Class} object represents a class, the return value is an array

     * containing objects representing all interfaces directly implemented by

     * the class.  The order of the interface objects in the array corresponds

     * to the order of the interface names in the {@code implements} clause of

     * the declaration of the class represented by this {@code Class} object.

     *

     * <p>If this {@code Class} object represents an interface, the array contains objects

     * representing all interfaces directly extended by the interface.  The

     * order of the interface objects in the array corresponds to the order of

     * the interface names in the {@code extends} clause of the declaration of

     * the interface represented by this {@code Class} object.

     *

     * <p>If this {@code Class} object represents a class or interface that implements no

     * interfaces, the method returns an array of length 0.

     *

     * <p>If this {@code Class} object represents a primitive type or void, the method

     * returns an array of length 0.

     *

     * <p>If this {@code Class} object represents an array type, the

     * interfaces {@code Cloneable} and {@code java.io.Serializable} are

     * returned in that order.

     *

     * @throws java.lang.reflect.GenericSignatureFormatError

     *     if the generic class signature does not conform to the

     *     format specified in section {@jvms 4.7.9} of <cite>The

     *     Java Virtual Machine Specification</cite>

     * @throws TypeNotPresentException if any of the generic

     *     superinterfaces refers to a non-existent type declaration

     * @throws java.lang.reflect.MalformedParameterizedTypeException

     *     if any of the generic superinterfaces refer to a parameterized

     *     type that cannot be instantiated for any reason

     * @return an array of interfaces directly implemented by this class

     * @since 1.5

     */

    public Type[] getGenericInterfaces() {

        ClassRepository info = getGenericInfo();

        return (info == null) ?  getInterfaces() : info.getSuperInterfaces();

    }

    /**

     * Returns the {@code Class} representing the component type of an

     * array.  If this class does not represent an array class this method

     * returns null.

     *

     * @return the {@code Class} representing the component type of this

     * class if this class is an array

     * @see     java.lang.reflect.Array

     * @since 1.1

     */

    public Class<?> getComponentType() {

        // Only return for array types. Storage may be reused for Class for instance types.

        if (isArray()) {

            return componentType;

        } else {

            return null;

        }