Dynamic linking of virtual machine stack of JVM

One 、 Premise ： In this article, we mainly explain dynamic links in stack frames （ References to runtime constant pool methods ）

Two 、 Concept ：

Let's take a look at the picture above , Sometimes we return a method to an address 、 Dynamic links 、 Some additional information is collectively referred to as the frame data area

（1） Each stack frame contains a reference to the method to which the stack frame belongs in the runtime constant pool , The purpose of including this reference is to support the code of the current method to dynamically link . such as ：invokdynamic Instructions .

（2） stay Java When the source file is compiled into a bytecode file , All variables and method references Are referenced as symbols , Save in class In the constant pool of files .

such as ： Describes when a method calls another method , It is represented by a symbolic reference to a method in the constant pool , that The purpose of dynamic linking is to convert these symbolic references into direct references to calling methods

eg:

After decompiling ：

Found that symbolic references to variables and methods exist in class Constant pool in file .

3、 ... and 、 Look at the diagram ：