Summary

Add constants in java.lang.constant.ConstantDescs to describe the names of instance and class initialization methods and a method type descriptor of "()V".

Problem

In Classfile generation and JDK itself, the names of these special methods are frequently used; having to define them in each use site is prone to typos that javac cannot catch easily.

Solution

Add INIT_NAME, CLASS_INIT_NAME, MTD_void to java.lang.constant.ConstantDescs class, representing the special name for instance initialization, class initialization methods and their common descriptor.

Specification

@@ -283,6 +283,33 @@ public final class ConstantDescs {
             = DynamicConstantDesc.ofNamed(BSM_GET_STATIC_FINAL,
                                           "FALSE", CD_Boolean, CD_Boolean);

+    /**
+     * The special name of instance initialization methods, {@value}. An instance
+     * initialization method has this special name and is {@code void}.
+     *
+     * @jvms 2.9.1 Instance Initialization Methods
+     * @since 21
+     */
+    public static final String INIT_NAME = "<init>";
+
+    /**
+     * The special name of class initialization methods, {@value}. A class
+     * initialization method has this special name, {@link java.lang.reflect.AccessFlag#STATIC
+     * ACC_STATIC} flag set, is {@link #MTD_void void} and takes no arguments.
+     *
+     * @jvms 2.9.2 Class Initialization Methods
+     * @since 21
+     */
+    public static final String CLASS_INIT_NAME = "<clinit>";
+
+    /**
+     * Nominal descriptor representing the method descriptor {@code ()V},
+     * taking no argument and returning {@code void}.
+     *
+     * @since 21
+     */
+    public static final MethodTypeDesc MTD_void = MethodTypeDesc.of(CD_void);
+
     static final DirectMethodHandleDesc MHD_METHODHANDLE_ASTYPE
             = MethodHandleDesc.ofMethod(Kind.VIRTUAL, CD_MethodHandle, "asType",
                                         MethodTypeDesc.of(CD_MethodHandle, CD_MethodType));