Personal understanding of symbolic references and direct references in Java virtual machines

In Java, a Java class will be compiled into a class file. At compile time, the Java class does not know the actual memory address of the reference class, so only symbolic references can be used instead. For example, the Org.simple.People class references the Org.simple.Tool class, and the people class does not know the actual memory address of the Tool class at compile time, so only the symbolic org.simple.Tool (assuming) can be used to represent the address of the Tool class. When the class loader loads the people class, you can get the actual memory address of the tool class from the virtual machine, so you can replace the symbol Org.simple.Tool with the actual memory address of the tool class and the direct reference address.