diff --git a/src/README.md b/src/README.md new file mode 100644 index 0000000..a0c26de --- /dev/null +++ b/src/README.md @@ -0,0 +1,84 @@ +#Java Course + +##Java basic + +### DATA TYPES + +There are 8 primitive data types in java :- + +1- Byte --> byte (numeric value) + +2- Short --> short (numeric value) + +3- Char --> char (can be used as for numeric value only character) + +4- int --> integer (numeric value) + +5- long --> Long (numeric value) + +6- float --> Float(numeric value eg : 9.87f) + +7- double --> Double(numeric value) + +8- boolean --> Boolean ( true and false) + +ranges are provided in code of all primitive data types . + +## Reference types in Java:- +1. class types − This reference type points to an object of a class. + +2. array types − This reference type points to an array. + +3. interface types − This reference type points to an object of a +class which implements an interface. + +**The main difference between primitive and reference type is that primitive type always has a value, it can never be null but +reference type can be null, which denotes the absence of value. + +##In Java there are four types of references differentiated on the way by which they are garbage collected. +Strong References. + +Weak References. + +Soft References. + +Phantom References. + + +## NAMING CONVENTIONS IN JAVA +1: camelCase ( it can be a fields / methods / packages ) +eg: bankAccountNumber + +2: PascalCase ( class name) +eg: MobileShop + +## Scope of a variable + +region + +it is a part of an program/software where the variable is defined to be accessible . + +on the basis of where it is defined : +- local to a method +- as a parameter to the method. +- class variable ( static / class owned ) +- in a different class + - local to method + + - as a parameter + + - class variable + + +## Types of Fields in class ( on the basis of ownership) + +1. class variable ( static / class owned ) +2. instance variable ( non-static / object owned ) + + +## Accessibility modifiers + +1. Private +2. Public +3. Protected +4. Default \ No newline at end of file diff --git a/src/takingInput/UsingScanner.java b/src/takingInput/UsingScanner.java index ab60836..1499309 100644 --- a/src/takingInput/UsingScanner.java +++ b/src/takingInput/UsingScanner.java @@ -8,9 +8,12 @@ public class UsingScanner { */ public static void main(String[] args) { System.out.println("Enter your name: "); + // for single input we can use this . + // java.util.Scanner scannerObject = new java.util.Scanner(System.in); Scanner scannerObject = new Scanner(System.in); + // for taking multiple input using one object e.i scannerObject . String inputName = scannerObject.nextLine(); - + // int number = scannerObject.nextInt(); System.out.println("The name is: " + inputName); } }