.

In this regard, what is the purpose of JDK?

The Java Development Kit (JDK) is a software development environment used for developing Java applications and applets. It includes the Java Runtime Environment (JRE), an interpreter/loader (Java), a compiler (javac), an archiver (jar), a documentation generator (Javadoc) and other tools needed in Java development.

Also, does tomcat need JDK? Tomcat does not require a JDK. It needs a JRE only. JSP compilation is done by the bundled Eclipse compiler. For example, jsp pages must be parsed and any Java code in them must be compiled on-the-fly.

Thereof, do I need both JDK and JRE?

You no need to install JRE then , JDK usually consists of both development & run-time environments in it. If you install JDK then JRE will be in it and installed automatically along with JDK. generally to do javac <filename. java> you need to have JDK which already have JRE in it. to do java filename you need only JRE.

What is difference between Java SE and JDK?

The JDK includes the compiler and other tools needed to develop Java applications; JRE does not. Within a given version of Java, this answer remains valid. JDK is the Java Development Kit, JRE is the Java Runtime Environment, Java SE is the standard edition, and so on. But the version 6 (1.6) is becoming antiquated.