Learn the core JVM framework design in the Java class library

Before learning the core JVM framework design in the Java library, let's first understand what JVM (Java Virtual Machine) is.JVM is a core component of the Java platform. It is a virtual computer above the operating system and is used to execute the Java bytecode.JVM has its own instruction set architecture and can run Java programs on different hardware and operating systems. The JVM framework design refers to the various design and optimization of the developer's JVM to provide better performance and functions.Below we will focus on the core JVM framework design in the Java class library. 1. Classloader (class loader): ClassLoader is responsible for loading the Java bytecode to JVM and converting it into executable code.It provides a mechanism of dynamic loading and isolation, so that applications can load different classes as needed at runtime. ClassLoader classLoader = MyClass.class.getClassLoader(); Class<?> myClass = classLoader.loadClass("com.example.MyClass"); 2. Garbage Collection (garbage recycling): In the process of JVM automatic management of memory, it will recover the objects that are no longer used and release memory.The garbage recovery device is responsible for monitoring the reference relationship of the object and regularly clean up the objects that are no longer used. System.gc (); // Manually trigger garbage recovery 3. Memory Management: JVM uses the memory of the two memory regions of the stack and the stack.It is used to store object instances, and the stack is used to store local variables and methods to call information. 4. JIT Compiler (Instant Compiler): JIT compiler converts the byte code to a machine code during runtime to improve the execution efficiency of the code.It will dynamically generate efficient machine code according to the execution of the program. // Enable the JIT compiler java -XX:+TieredCompilation MyClass 5. Reflection: The reflection allows the program to check and modify the class, attributes and methods during runtime.It provides a dynamic operation method that allows the Java program to have higher flexibility and scalability. Class<?> myClass = MyClass.class; Field field = myClass.getDeclaredField("myField"); field.setAccessible(true); field.set(null, "New Value"); 6. Exception Handling: JVM provides an abnormal processing mechanism that can capture and process abnormalities in the program.It allows developers to write code with robustness and reliability. try { // Perhaps abnormal code } catch (Exception e) { // Abnormal processing code } The above is some of the core JVM framework in the Java library.Through in -depth learning and understanding these designs, you can better use the functions provided by the Java class library and write efficient and stable Java applications.