Internal Details of Hello Java Program
In the previous section, we learned how to write a simple Java program, compile it and then execute it. In this section, we will learn the inner workings during the compilation and execution of the Java Program.
Compile Time Process:
What happens at runtime?
After the Java code is compiled to the byte code, a .class file is generated. This class file is loaded by the Classloader which is a subsystem of Java Virtual Machine (JVM).
The Bytecode Verifier checks the loaded class file for the illegal codes that may violate the object access rights.
After the code is verified, the Interpreter reads the bytecode stream and then executes the instructions.
Classloader:It is the subsystem of JVM that is used to load class files.
Bytecode Verifier: Checks the code fragments for illegal code that can violate access rights to objects.
Interpreter: Read bytecode stream then execute the instructions.