Java SE

Java Fundamentals and concepts

What is java?

Java was originally developed by James Gosling. It was released in May 1995.

Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers write once, run anywhere (WORA).

You can install Java SE for free here:

https://www.oracle.com/java/technologies/java-se-glance.html

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Java Primitive Data Types

data Type	Size	Description	Declaration example
byte	1 byte	Stores whole number from -128 to 127	byte variableName = value;
short	2 bytes	Stores whole numbers from -32,768 to 32,767	short variableName = value;
int	4 bytes	Stores whole numbers from -2,147,483,648 to 2,147,483,647	int variableName = value;
long	8 bytes	Stores whole numbers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807	long variableName = value;
float	4 bytes	Stores fractional numbers. Sufficient for storing 6 to 7 decimal digits	float variableName = number.deciaml
double	8 bytes	Stores fractional numbers. Sufficient for storing 15 decimal digits	double variableName = number.decimal
boolean	1 bit	Stores true or false values	boolean variableName = true/false
char	2 bytes	Stores a single character/letter or ASCII values	char varaibleName = ‘b’ or 98

Java Non-primitive Data Types

data Type	Description	Declaration example
String	Contains a collection of characters surrounded by double quotes	String variabmeName = “Hello”;
Arrays	Stores multipe variables of the same type in a single variable.	variableType[] variableName;
Clases	Everything in java is associated with a classes and objects with it’s own attributes and methods	public class className {}
Interface	Is a blueprint of a class. It contains static constants and abstract methods.	interface <interfaceName>{ }

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UNDER CONSTRUCTION

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Split method:

You can split a string with the split function.

First you need to declare a List of string. Then, use the .split method with the desired separator to split the string.

Example: String [] list = stringName.split(“desired character”);