Run time data areas
- 1. Java RunTime Data Areas
- 2. JDK VS JRE vs JVM Similarity JVM, JRE and JDK are platform dependent because configuration of each OS differs. But, Java is platform independent. JVM (Java Virtual Machine) ● ~ is an abstract machine ● ~ is a specification that provides runtime environment in which java bytecode can be executed. ● ~ are available for many hardware and software platforms.
- 3. JDK VS JRE vs JVM The JVM performs following main tasks: ● Loads code ● Verifies code ● Executes code ● Provides runtime environment
- 4. JDK VS JRE vs JVM JRE ● ~is an acronym for Java Runtime Environment. ● ~ is used to provide runtime environment. ● ~ is the implementation of JVM. ● ~ physically exists. ● ~ contains set of libraries + other files that JVM uses at runtime. ● ~ released and maintained by Sun Micro
- 5. JDK VS JRE vs JVM JDK ● ~is an acronym for Java Development Kit. ● ~physically exists. ● ~ It includes: + Java Runtime Environment (JRE), + an interpreter/loader (Java), + a compiler (javac), + an archiver (jar), + a documentation generator (Javadoc) and other tools needed in Java development.
- 6. JDK VS JRE vs JVM
- 7. In Depth JRE (How does JRE works) JRE consists of the following components: ● Deployment technologies: ○ deployment, Java Web Start and Java Plug-in. ● User interface toolkits: ○ AWT, Swing, Java 2D, Accessibility, Image I/O, Print Service and more. ● Integration libraries: ○ JDBC, IDL, JNDI, RMI etc ● Other base libraries: ○ I/O, i18, Beans, Math, Networking etc.
- 8. In Depth JRE (How does JRE works) ● Lang and util base libraries: ○ lang and util, management, versioning, zip, instrument, reflection, Collections, Concurrency Utilities, Java Archive (JAR), Logging, Preferences API, Ref Objects and Regular Expressions. ● Java Virtual Machine (JVM): ○ including Java HotSpot Client and Server Virtual Machines.
- 13. JVM Run-Time Data Areas
- 14. JVM Run-Time Data Areas Individual Thread : ● Not Shared ● created when a new thread is created ● include program counter register, JVM Stack, and Native Method Stack ○ is used to control each execution of each thread ○ contains frames, throws StackOverFlow error when stack get full ○ is used to support native methods
- 15. JVM Run-Time Data Areas Frame: a frame is pushed to the stack when a method is invoked
- 16. JVM Run-Time Data Areas Shared by All Threads All threads share Heap and Method Area ● Heap: ○ most frequently deal with area. ○ It stores arrays and objects, created when JVM starts up. ○ Garbage Collection works in this area. ● Method Area: ○ stores run-time constant pool, field and method data, methods and constructors code。 ●
- 17. JVM Run-Time Data Areas Shared by All Threads All threads share Heap and Method Area ● Runtime Constant Pool: ○ ~is a per-class or per-interface run-time representation of the constant_pool table in a class file. ○ contains several kinds of constants, ranging from numeric literals known at compile-time to method and field references that must be resolved at run-time.
- 18. Heap Details
- 19. java -Xms=1M -XmX=2M "Class Name" java -Xss=512M "Class Name" Source: https://www.linkedin.com/pulse/understanding-difference-between-jdk-jre-jvm-important-kumar/ https://www.geeksforgeeks.org/differences-jdk-jre-jvm/ https://dzone.com/articles/jvm-run-time-data-areas https://www.hackerearth.com/practice/notes/runtime-data-areas-of-java/