Java

Java

1. Applet

   • Runs within a browser.

2. Application

   • Stand-alone.

3. Object-Orientated

   • Everything in Java is an object (extended from this class).
   • Objects/Classes
     • Object Form
     • Wrappers
       • Wrappers

4. .java

   • source-code
   • compiler
     • into byte-code
     • .class
       • byte-code (low level)
       • interpreter
         • interpretation by JVM
         • JVM
           • Java Virtual Machine. The program is run on this. Because all Java programs run on the JVM, the prerequisite for Java programs to run is then simply the JVM. Any machine that can install and run the JVM can run java programs.

5. Primitives

   • boolean (1), byte (8), short (16),  int (32), long(64), float (32), double (64), char (16)

6. main method

   • public static void main(String[] args) When present in a class, means the class can be run as a program. The string args can be passed by the console as arguments as the program is invoked.

7. Generic Keywords

   • static, final, private, protected, public

8. Scope

   • Instance/Global
     • Class attributes. Can be accessed anywhere within class.
   • Local
     • Only accessible in code block which it was constructed.

9. Garbage Collection

10. Key Terms

    • Statements
    • Expressions
      • Formula. Evaluating yields a value.
    • Selections
      • If-else. Switch.
    • Access Modifiers
      • public, protected, package private, private

11. Input/Output (I/0)

    • Input/Output (I/O)

12. Exceptions

    • Exceptions

13. Equivalence

    • Boolean comparison between two values.

14. Autoboxing/Unboxing

    • Automatic conversion of primitive to wrapper and vice versa where required.

15. this

    • Mainly used as a disambiguation tool.

16. Stack and Heap

17. Short-circuiting

    • For an "AND", if the former is false then the expression is false, regardless of the other conditions.
    • For an "OR", if the former is true, then the expression is true, regardless of the other conditions.

18. Bitwise Operations

19. PATHS

20. Testing