JRE and JDK

--1, JRE and the JDK
 -1, the JRE (Java Runtime Environment Java Runtime Environment)
 -2, including the Java Virtual Machine (JVM Java Virtual Machine) and the required core class libraries and other Java programs, if you want to run eleven develop good Java programs, the computer can only be installed JRE.
 -3, JDK (Java Development Kit Java Development Kit I)
 -4, the JDK is available to Java developers, which contains the java development tools, including the JRE. So install the JDK, do not install the JRE in a separate, jre after jdk11 have to add their own jre
 -5, where I developed tools: compiler tools (javac exe) package tool jar.exe), etc.
 -6, simple terms: java using JDK development program completed, to the JRE to run.