The acronym for JDK is “Java Development Kit” released by Oracle corporation. The acronym for JRE is “Java Runtime Environment” which is also released by Oracle corporation.
It is a package of software which can be used to develop software based in Java. Basically, you will need it to program in Java. As the name implies, it is an Environment. It is a collection of directories with files related to Java. It has Java Virtual Machine on which Java programs run basically.
JDK is also a collection of directories but it actually also contains a directory called JRE, among others. It has directories like /bin, /lib./bin contains executable programs like “java” and “javaw”.
It is basically needed for development. It is required for running java programs.
It needs a larger disk space as it contains development tools as well as the JRE. It takes lesser space on disk as it is smaller.
It includes files required to write Java applets and Java applications. It includes additional components to run applications and applets written in Java.
JRE that is included in JDK provides debug information related to Java system classes. The JRE that is not included in JDK i.e. the Regular JRE does not include debug information related to system classes like ArrayList and String to improve performance.
If you want to develop Java software, you need to install only JDK. It is not necessary to install JRE as it is already included within the JDK. If you only want to run Java programs, you can install only JRE. But there can be a few scenarios where even if you have not planned to perform any Java development, even then you need to install JDK. For example, while deploying a webApp in JSP.
It includes the “javac”, the Java compiler. It compiles Java code into Java bytecode, After that the Java interpreter i.e. “java” command interprets the Java bytecode. It has browser plugins to execute Applets. Applets are small programs written in Java which can be launched from HTML. They cannot be run by the Operating System directly. It is launched by the user and is then executed within a JVM.
It includes tools to monitor Java applications.There are JVM Process Status Tool , JVM Statistics Monitoring Tool etc. It includes tool called Java Web Start to deploy Java applications on Server. It also has stand-alone Java VM (HotSpot),
This is the most vastly used Software Development Kit. Actually, JDK is just an extended subset of SDK. You can download it free of cost from https://www.oracle.com/technetwork/java/javase/downloads/. It can be downloaded free of cost from https://www.java.com.
The latest version of JDK by today’s date Is JDK 8 and the latest update release is JDK 8u45. The latest version of JRE is JRE 1.8 as of now.
JDK is provided by other vendors also, not only by Oracle. Examples of other JDKs are Azul systems, OpenJDK/IcedTea, GNU‘s Classpath and GCJ (The GNU Compiler for Java). JRE is provided by Oracle.
It has tools like compilers and debuggers which are required for development of applets and Applications. It acts as the foundation for J2EE (Java 2 Platform, Enterprise Edition) technologies for development and deployment of enterprise software.
Typically, there are one (or more) JREs in JDK among other tools which help to develop and compile Java classes. The Java program files can be run on different Operating systems. This advantage is allowed by the execution engine i.e. Java Virtual Machine
Installation :·

  • Download the installer.
  • Run the JDK installer
  • Update the PATH variable (optional step)
  •   Start using JDK.

  • Download the installer.
  • Run it.
  • Default options are Okay.