Relationship between SDK, JDK, JRE, and JVM

SDK (Software development Kit) is used to help developers improve work efficiency. Different types of software development can have their own sdks. Windows SDK, DirectX SDK, And. net sdk. JAVA Development is also unambiguous and has its own Java SDK. Java SDK was first called Java Software Develop Kit and later renamed JDK, namely Java Develop Kit. As a Java Development Kit, JDK is mainly used to build applications, applets, and components running on the Java platform. JRE (Java Runtime Environment, Java Runtime Environment), that is, the Java platform. All Java programs can run only under JRE. JDK tools are also Java programs, and JRE is also required to run. To ensure JDK independence and integrity, JRE is also a part of JDK installation. Therefore, there is a directory named jre under the JDK installation directory to store JRE files. JVM (Java Virtual Machine) is a part of JRE. It is a fictitious computer that simulates various computer functions on an actual computer. JVM has its own complete hardware architecture, such as processor, stack, and register, as well as corresponding command systems. The most important feature of Java is cross-platform running. JVM is used to support cross-platform operations that are irrelevant to the operating system. Clearly shows the relationship between JDK (Java SDK), JRE, and JVM: