Deep exploration of the JVM core architecture in the Java library

Deep exploration of the JVM core architecture in the Java library Summary: Java virtual machine (JVM) is the core component of the Java program.Understanding the core architecture of JVM is essential for developing efficient and stable Java applications.This article will explore the core architecture of the JVM in the Java class library and provide some Java code examples to help readers better understand. introduction: JVM is the key component of the Java platform, which is responsible for explaining and executing the Java bytecode.JVM is a virtual computer, which provides functions such as memory management, garbage recovery mechanism and thread management, so that the Java program can run across platforms.Understanding the core structure of JVM can help developers better optimize the performance and reliability of the application. 1. The core component of the Java virtual machine 1. Classloader: The class loader is responsible for loading the compiled Java bytecode to the JVM.It is divided into a startup class loader, extended loader and application class loader.Developers can also customize class loaders to meet specific needs. Example code: ClassLoader classLoader = MyClass.class.getClassLoader(); 2. Data area when runtime: JVM divides memory into different areas during runtime, including heaps, stacks, method areas, and PC registers.Each area has different functions, such as stacks for storing object instances, stacks for storage method calls and local variables. Example code: int Age = 25; // Local variables are stored in the stack 3. Execute engine: The execution engine is the core part of JVM, which is responsible for explaining and executing the Java bytecode instruction.JVM can use the interpreter and instant compiler (JIT) to execute the byte code.The interpreter explains the byte code instruction one by one, and JIT compile the byte code into the local machine code for execution, thereby improving the execution efficiency of the program. Example code: for (int i = 0; i < 10; i++) { System.out.println(i); } Second, garbage recycling mechanism JVM's garbage recovery mechanism is a key component of automatic management of memory.It recycled memory that is no longer used by labeling-clearing, copying and marking-sorting algorithms.In this way, developers do not need to manually release memory, which greatly simplifies the complexity of memory management. Example code: String str = "Hello World"; str = null; // Place the object to null, wait for the garbage recyrior to recycle Third, performance tuning and fault diagnosis Understanding JVM's core architecture is essential to optimize the performance of the Java application and the diagnosis of fault diagnosis.Developers can use tools such as Java virtual machine diagnosis tools (JVMSTAT tools provided by JDK) for performance analysis and fault investigation.You can also improve the performance of the application by adjusting the configuration parameters of the JVM. Example code: java -Xmx1024m -Xms512m MyClass in conclusion: In -depth understanding of the JVM core architecture in the Java class library is essential for developing efficient and stable Java applications.This article introduces key content such as JVM's core components, garbage recycling mechanisms, and performance tuning and fault diagnosis, and provides related Java code examples.Through further learning and practice, developers can better use JVM functions to build high -efficiency and reliable Java applications. references: [1] Oracle. The Java Virtual Machine Specification. https://docs.oracle.com/javase/specs/jvms/se16/html/index.html [2] Oracle. Troubleshooting Guide for Java SE 16. https://docs.oracle.com/javase/16/troubleshoot/index.html