What is the difference between JDK and JRE?

Question

What is the difference between JDK and JRE?
What are their roles and when should I use one or the other?

Answer 1

The Java Development Kit (JDK) is a software development environment which is used to develop java applications.The java development kit may be described as a set of directories, it is basically a superset of Java Runtime Environment (JRE).

JRE stands for Java Runtime Environment and is many times also written as Java RTE. What JRE does is it provides the minimum requirements for running a Java application. It primarily consists of the Java Virtual Machine (JVM), its core classes.

Usually, when we only need to run Java programs on browser or computer only JRE is required. But if we want to do some Java development, then additionally JDK is required.

To put the difference clearly, JRE is a subset of JDK.

JDK = JRE + Development/debugging tools