https://github.com/Cydeo-Alumni/JavaProgrammingFastTrack7.git

Day 01:

How is your java experience?How do you rate your java skill? Do you have experience with java? etc

I have 5 years of java programming experience. I used java for building automation frameworks and test automation development. I am comfortable with core java, flow control, string manipulation, collections, Object oriented programming, exception handling, debugging using java.

Why did you choose java for automation?

Java is high level object oriented language. It is platform independent It has many open source libraries for test automation. JUnit, TestNG, Selenium , JDBC, RestAssured etc It is a popular language for web backend , mobile development, so using java for automation is makes it in sync with developer environment.

Which java version? I used java 8 mostly in my automation projects. Switched to java 11 in current project.

Jdk, jre, jvm?

Jdk - Java dev kit -> is needed for java development. It contains compiler and JRE, JVM.

JRE -> Java runtime environment -> used to run compiled java code(bytecode), uses JVM to run

JVM -> java virtual machine -> used to run java compiled bytecode

================ Explain main method: public static void main(String[] args)

Main method, is called by Jvm to start execution of java program.

public -> access modifier, can be accessed from anywhere static -> method can be called without creating object void -> does not return any value main -> method name String[] args -> String array parameter where we can pass values to main method

============== Explain: System.out.println("Hello World");

System is a class in java.lang package out -> static variable of PrintStream type: public static final PrintStream out println -> is a void method in PrintStream class "Hello World" -> is a input to be printed out

println is overloaded method, so we can pass all kinds of inputs. Ex: System.out.println("Hello World"); System.out.println(333);

Data types: primitives and non-primitives byte, short, int, long float, double char boolean

var type automatically detects data type for local variables. And need to initialize in same statement

var v = 10;

non-primitives -> are object types that comes from a class String, Scanner, ChromeDriver etc

Object class is root/parent class for all classes in java. public class Object {} can also be used as data type.

Object obj = new String("abc");

Sometimes, when we write a class, we want to be able to use for all types. In that case we can use Generic type.

public class Device<T> { T value; }

What are Wrapper classes: Each primitive has a matching Wrapper class. Primitives are just values without any behaviour. Wrapper classes add behaviour to primitives also ability to become an object. We can use wrapper types with java collections. Java collections does not work with primitives. Only array can work with both

byte -> Byte short -> Short int -> Integer long -> Long float -> Float double -> Double char -> Character boolean -> Boolean

=======================

//compare 2 numbers System.out.println("larger int = " + Integer.max(10, 5)); System.out.println("sum of double = " + Double.sum(4343.2, 12.4));

//convert from String to wrapper type: String strAge= "44"; int age = Integer.parseInt(strAge); Integer age = Integer.valueOf(strAge);

=======================

Autoboxing vs Unboxing?

Autoboxing -> converting from primitive to wrapper object Integer i = 11;

Unboxing -> converting from wrapper object to primitive Integer i = 11; int n = i;

What do you do if you have a really large number that is not fitting LONG?

BigInteger, BigDecimal types can be used for really large numbers that we cannot predict.

Internally they use arrays to store numbers.

Casting primitives.

converting from one type to another:

from byte to int from int to short byte n1 = 11; int n2 = n1; //cast from small to large automatically

int n3 = 200; byte n4 = (byte)n3; //cast from large to small

Variables: local vs instance?

local variable declared inside the method or a block. and scope is limited to that block.

instance variable declared inside the class, outside the methods.
scope is whole class

=======================

DAY 02:

Operators: -arithmethmetic/math(+,-,/,%,*) -shorthand, unary (+=, -=, ++, --) -> pre , post increment/decrement pre -> ++n; post -> n++;

-comparison -> >, <, !=, == etc -logical -> &, &&, |, ||, !, ^

XOR operator ^ -> returns true only when conditions are different.

if both conditions are same, it will return false.

boolean a = true; boolean b = false; a ^ b => true

boolean a = true; boolean b = true; a ^ b => false a || b => true

Conditional statements:

1. if statements

2. switch

3. ternary ----=

4. if statement: if(condition) { //code }

   if(condition) { //code to run when true } else { //code to run when false }

   if(conditionA) { //code to run when A is true } else if(conditionB) { //code to run when B is true } else if(conditionC) { //code to run when C is true } else { //code to run when all above are false }

   if(conditionA) { if(conditionB){ //code B }else { //Code C } //code D } else { Code E }

   conditionA and ConditionB are true -> B, D conditionA is true and ConditionB is false -> C, D conditionA is false, ConditionB is true -> E

switch(variable) { //String, int, Enums case 1: //code to run when case 1 is match break; case 2: //code to run when case 2 is match break; default: //when all cases mismatch }

=======================

var myVar = (conditionA) ? value when true : value when false

String str; if(conditionA) { str = value when true } else { str = value when false }

=======================

When to use: if statements are most flexible, and can be used with all kind of conditions. paired with logical operator. ||, && etc, >, <

if(a > b || a < c) {

}

we can use switch when we are comparing if variable EQUALS certain values. cannot handle other types of comparisons

switch(a) {
	case "ABC":
		//code
		break;
	case "RRT12":
		//code
		break;
}

ternary can be used to replace basic simple if else statement.

===============================

LOOPS in java:

while, do while, for loop, for each loop

we can have nested loops

forEach method can also be used with collections

while(conditions is true) { //keep running this code }

do { //Do this once, then keep doing while condition is true }while(conditions is true);

while vs do while?

while loop checks condition first and runs loop block code if true.

do while runs loop block code once, then checks if conditions is true.

---

for loop with iterator, can be used when we know number of iterations beforehand.

for(int i = 0; i <= 100; i++) { //loop code }

for each loop is used with arrays, collections. it will start from first element until the last element.

int[] nums = {43, 123, 53};

for(int n : nums) { println(n); }

String[] strs = {"43", "123", "53"};

for(String s : strs) { println(s); }

String: String is a class in java lang package. String can store "value" in double quotes, and uses final char[] array internally.

String pool is an area in Heap memory where string objects are stored and can be reused.

String a = "java"; String b = "java"; "java" is created in String pool, since we are using double quotes to create a String. One object is created and reused

if(a == b) ==> true. both are pointing to same object in string pool

---

String a = new String("java"); String b = new String("java");

We are using NEW keyword, 2 objects are created outside String pool.

a == b ==> false because a and b are referring to different objects.

a.equals(b) => true a.equalsIgnoreCase(b) => true

================

DAY 04:

Methods: -> when I am assigned automation task during sprint planning. -> analyze -> make sure steps, and acceptance criteria is CLEAR. Ask from BA, Dev, other team member if not clear -> in progress: -> test manually, if any bugs, report them. Most bugs can be caught here -> testing manually: make it more clear about functionality, test data requirements, steps etc deeper. -> start automation: -> look at framework and see if any similar scenario was automated before -> look at any steps in this scenario are common to other tests that were automated before -> if yes, look at what REUSABLE methods, utilities, page object elements/methods can be reused. -> When writing doing automation development, please focus on reusability.

COMMAND/CTRL+SHIFT+F -> global search in IntelliJ

Methods:

Help create reusable code Void -> performs actions, does not return value. -> Ex: setter method

Return -> method that performs actions, then returns value. We use return keyword to return value

Method that with or without parameters.

Void + no params: public static void m1() {}

Void + with params: public static void m2(String str, int num){}

Return + no params: public static int m3(){ return 2024; }

Return + with params: public static boolean m4(int num) { return num > 0; }

To make our code more Reusable => methods: -> general reusable methods(reverseString )/utility methods: configReader etc -> application specific reusable methods(page object methods)

Naming of methods: -> code readability. -> make sure method, and variable names are in alignment of naming conventions in your project

Method overloading:

2 or more methods with SAME NAME, DIFFERENT PARAMETERS.

DIFFERENT: data types of params, number of params, or order of params different

public void m1(){} public void m1(String str){} public boolean m1(boolean bl){} public boolean m1(int n1