Java Platform Standard Edition 8 Documentation

Oracle has two products that implement Java Platform Standard Edition (Java SE) 8: Java SE Development Kit (JDK) 8 and Java SE Runtime Environment (JRE) 8.

JDK 8 is a superset of JRE 8, and contains everything that is in JRE 8, plus tools such as the compilers and debuggers necessary for developing applets and applications. JRE 8 provides the libraries, the Java Virtual Machine (JVM), and other components to run applets and applications written in the Java programming language. Note that the JRE includes components not required by the Java SE specification, including both standard and non-standard Java components.

The following conceptual diagram illustrates the components of Oracle's Java SE products:

Description of Java Conceptual Diagram

JDK		Java Language	Java Language
		Tools & Tool APIs	java javac javadoc jar javap jdeps Scripting Security Monitoring JConsole VisualVM JMC JFR JPDA JVM TI IDL RMI Java DB Deployment Internationalization Web Services Troubleshooting
	JRE	Deployment	Java Web Start Applet / Java Plug-in
		User Interface Toolkits	JavaFX
			Swing Java 2D AWT Accessibility Drag and Drop Input Methods Image I/O Print Service Sound		Java SE API
		Integration Libraries	IDL JDBC JNDI RMI RMI-IIOP Scripting	Compact Profiles
		Other Base Libraries	Beans Security Serialization Extension Mechanism JMX XML JAXP Networking Override Mechanism JNI Date and Time Input/Output Internationalization
		lang and util Base Libraries	lang and util Math Collections Ref Objects Regular Expressions Logging Management Instrumentation Concurrency Utilities Reflection Versioning Preferences API JAR Zip
		Java Virtual Machine	Java HotSpot Client and Server VM

Source: http://docs.oracle.com/javase/8/docs/