Following are the key components and their responsibility in JVM.
Classloader − Loads the class file into the JVM.
Class Area − Storage areas for a class elements structure like fields, method data, code of method etc.
Heap − Runtime storage allocation for objects.
Stack − Storage for local variables and partial results. A stack contains frames and allocates one for each thread. Once a thread gets completed, this frame also gets destroyed. It also plays roles in method invocation and returns.
PC Registers − Program Counter Registers contains the address of an instruction that JVM is currently executing.
Execution Engine − It has a virtual processor, interpreter to interpret bytecode instructions one by one and a JIT, just in time compiler.
Native method stack − It contains all the native methods used by the application.