Module java.base

Package java.lang.runtime

Class ObjectMethods

java.lang.Object

java.lang.runtime.ObjectMethods

public class ObjectMethods
extends Object

This class is associated with records, a preview feature of the Java language. Preview features may be removed in a future release, or upgraded to permanent features of the Java language.

Bootstrap methods for state-driven implementations of core methods, including Object.equals(Object), Object.hashCode(), and Object.toString(). These methods may be used, for example, by Java™ compiler implementations to implement the bodies of Object methods for record classes.

Since:

14

Method Summary

Modifier and Type	Method	Description
static Object	bootstrap(MethodHandles.Lookup lookup, String methodName, TypeDescriptor type, Class<?> recordClass, String names, MethodHandle... getters)	Bootstrap method to generate the Object.equals(Object), Object.hashCode(), and Object.toString() methods, based on a description of the component names and accessor methods, for either invokedynamic call sites or dynamic constant pool entries.

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

bootstrap

public static Object bootstrap(MethodHandles.Lookup lookup, String methodName, TypeDescriptor type, Class<?> recordClass, String names, MethodHandle... getters) throws Throwable

Bootstrap method to generate the Object.equals(Object), Object.hashCode(), and Object.toString() methods, based on a description of the component names and accessor methods, for either invokedynamic call sites or dynamic constant pool entries. For more detail on the semantics of the generated methods see the specification of Record.equals(Object), Record.hashCode() and Record.toString().

Parameters:

lookup - Every bootstrap method is expected to have a lookup which usually represents a lookup context with the accessibility privileges of the caller. This is because invokedynamic call sites always provide a lookup to the corresponding bootstrap method, but this method just ignores the lookup parameter

methodName - the name of the method to generate, which must be one of "equals", "hashCode", or "toString"

type - a MethodType corresponding the descriptor type for the method, which must correspond to the descriptor for the corresponding Object method, if linking an invokedynamic call site, or the constant MethodHandle.class, if linking a dynamic constant

recordClass - the record class hosting the record components

names - the list of component names, joined into a string separated by ";", or the empty string if there are no components. Maybe be null, if the methodName is "equals" or "hashCode".

getters - method handles for the accessor methods for the components

Returns:

a call site if invoked by indy, or a method handle if invoked by a condy

Throws:

IllegalArgumentException - if the bootstrap arguments are invalid or inconsistent

Throwable - if any exception is thrown during call site construction