First, understand the concept:
1, JDK (Java Development Kit Java Development Kit)
JDK is available to Java developers, which contains Java development tools, including JRE, so the installed JDK, do not install the JRE alone.
Including development tools: compiler tools (javac.exe) Packaging Tool (jar.exe), etc.
2, JRE (Java Runtime Environment Java Runtime Environment)
Including the Java Virtual Machine (JVM Java Virtual Machine) and Java programs required core class libraries, if you want to develop a good run Java programs, computer seed only need to install JRE can be.
3, JVM is Java Virtual Machine (Java Virtual Machine)
JVM is a specification for a computing device, which is a fictional computer, is passed over the actual computer simulation of various computer-implemented functions.
Second, the relationship diagram
JDK≥JRE≥JVM
