JRE and JDK is a name of a java download bundle. Generally, when a version of Java, say version 11 is ready for download, it will be bundled as JRE and JDK.

JRE -> Java Runtime Environment. This is what most will want to download and use to run ResponseMaster. This provides a runtime version of Java and does not include any of the components used to build applications using Java. For a version of Java there are generally three distribution

JDK -> Java Development Kit. This provides all the java components required to develop, build and distribute Java application.