JDK Contains various APIs and libs like Java.io, javac, java etc It gives the required packages for java developer to work on JVM and jre JRE It is runtime environment, which implements JVM and provides all class libraries and other files that JVM requires at runtime JVM It is where the bytecode is executed

Process vs thread

A process is a running instance of program over OS – A thread is running on top of process – OS, there is multi processing on OS level – Multiple thread, multi threading in process level – Process run on separate memory space – Thread runs on shared memory space