The document discusses key concepts in Java programming including: 1. Java is an object-oriented programming language that is platform independent and allows developers to create applications, applets, and web applications. 2. The Java code is first compiled to bytecode, which can then be executed on any Java Virtual Machine (JVM) regardless of the underlying hardware or operating system. 3. Core Java concepts covered include classes, objects, encapsulation, inheritance, polymorphism, and abstraction. Operators, flow control statements, arrays, strings and object-oriented programming principles are also summarized.

1. Core Java - Sharad Ballepu [email_address] www.sharmanj.com

4. Introduction – Java Virtual Machine .class file Java Virtual Machine .java file Java Compiler UNIX Microsoft Mac

9. Introduction – Java Keywords throw this synchronized switch super strictfp static short return public protected private package new char catch case byte break boolean abstract volatile interface for do void int float default assert while try transient throws native long instanceof import implements if goto finally final extends else double continue const class

12. Introduction - Data Types General rule: Min value = 2 (bits – 1) Max value = 2 (bits-1) – 1 (where 1 byte = 8 bits) true, false - - - boolean 2 16 – 1 - - 2 63 – 1 2 31 – 1 2 15 – 1 2 7 – 1 Max Value ‘ a’, ‘’ 123.86 1.0 123456 12345, 086, 0x675 1234 123 Literal Values - 8 double 0 2 char - 4 float -2 63 8 long Min Value Bytes Data type -2 31 4 int -2 15 2 short -2 7 1 byte

13. Java Modifiers static volatile native synchronized transient strictfp abstract final default protected private public Modifier Method Variables Methods Class Variables Class

27. Arrays and Strings – Arrays Representation myArray int[ ] myArray = {1,2,3,4,5} Heap 5 4 3 2 1

31. OOPS Explored - Encapsulation My YouTube videos My Cute puppy My Wedding Gift My YouTube videos My Cute puppy My Wedding Gift My YouTube videos My Cute cat My Hawaii trip I can share my puppy video with everyone I want to share my wedding gift only with my friends

36. Exceptions – Exception Hierarchy Throwable Exception Error Unchecked Exception Checked Exception

39. Exceptions – try-catch-finally flow Put exception code in try More exceptions To handle? Handle exceptions In catch? Execute finally? END Handle exception In the catch block Clean-up code in finally yes yes yes no no no

40. Garbage Collection

42. Garbage Collection A1 A2 A a = new A(); a.Name = ‘A1’; a = A2; A1 A a = new A(); a = null; A C B Reassign Reference Set null Islands Of Isolation

44. Collections – Arrays v/s Collections abc def jkl ghi abc 123 def new Person() Arrays Collections

45. Collections - Overview LinkedHashSet

51. Threads - Introduction TIME User validation Process report maintenance TIME User validation Process report maintenance EXECUTION EXECUTION Multi-threaded environment

52. Threads - Creation public Class MyThread implements Runnable { public void run() { System.out.println(“In Thread”); } } To Invoke: MyThread t1 = new MyThread(); Thread t = new Thread(t1); t.Start(); public Class MyThread extends Thread { public void run() { System.out.println(“In Thread”); } } To Invoke: MyThread t1 = new MyThread(); t1.start(); Implementing the Runnable Interface Extending the Thread Class

53. Threads – Thread Life cycle runnable end blocked start running T1 T2 T1 T2 T1 T2 T1 T1 T2

55. Threads – Synchronization Account Account acct = getAccount (123); MyThread t1 = new MyThread(acct); MyThread t2 = new MyThread(acct); t1.start(); t2.start(); shared object public class Account { private int bal; private int acctId; … public Account(int acctId) { this.acctId = acctId; } public boolean withdraw(int amt) { if (bal > 0) { // give money // other related activities bal = bal – amt; } } } run() run() T1 stack T2 stack acct acct 100 140 50 100 90 100

56. DEMO