Java Class - 1

Initial Setup Instructions

• Installing JDK + JRE

• Installing Jetbrains

• Setting Up Windows cmd For Java

Resources

• Head First Java: One of the best Java book for beginners.

• Core Java Volume 1: Covers both basics and advanced topics in Java, Highly recommened for those who are already familiar with Java.

• The Complete Java Reference: Another great book covering basics of Java in crisp and concise manner.

• Oracle Docs: Best resource for learning Java, all you have to learn is how to search the docs :P. Recommend for advanced users.

• Java TPoint: Great online resource for learning Java concepts.

• Bucky Roberts Video Series: Great youtube playlist to learn java in a fun manner.

Java Basics and Useful Links

• Java is an object oriented, class-based, concurrent, secured programming language.

• Initiators: James Gosling, Mike Sheridan, and Patrick Naughton

• Features of java:
  1. Write once run anywhere
  2. Multithreated
  3. Security
  4. Built in graphics
  5. Object Oriented language
  6. Support Multimedia
  7. Open product
  8. Platform independent
• Command to set temporary path in cmd
  • set path=C:\Program Files\Java<jdk_folder_name>\bin
• Compilation:
  • Compile time
    • javac fileName.java
    • Class -> Compiler -> Bytecode
  • Runtime
    • java fileName
    • classfile -> classloader -> bytecode verifier -> interpreter -> runtime -> hardware
• JDK
  • Compiler(javac), tools(javap, java) + JRE
• JRE
  • JVM + Euntime Environment
  • Provide set of software tools which are used for developing Java applications.
  • It is used to provide the runtime environment.
  • JRE implements JVM.
  • Since JRE is implementation of jvm therefore is also released by different other companies (openjdk, oraclejdk)
• JVM
  • Can run anything compiled to bytecode. It is a virtual machine.
  • JVM is system dependent.

  • Functions of JVM Loads code Verifies code Executes code Provides runtime environment

    therefore used to convert and run bytecode line by line. bytecode -> machine code -> run that line

  • How JVM Works
  • JDK vs JRE vs JVM
• JIT
  • line by line, hence –> performance problem – (solution needed) –> jit
  • Hepls java interpreter to run and execute code faster
  • Refer this link
  • Two observations firstly of repeated code segments, secondly wrongly written code.
• Classes and Objects
  • Refer the ppt for all the theory and examples
  • this reference in Java
  • instance vs static methods in java
  • Refer this code for basic syntax and this code for Mutator Example