How to create a Java Program -

*Step-1: write a syntax of Java Program

//Begining of a class name.

//Begining of a Method of Java program.

//End of a method name.

//End of the class name.

//class Class Name{}.

*Step-2: Save your program with the same ClassName.

*Step-3: compile the code with the command "JAVAC ClassName".

*Step-4 Now run the program code on command prompt with command "JAVA ClaasName".

Definition of Main words using in the program -

*Public - This word using for access outside of class.

*Static - This word is using for code, they can run itself without an object.

*Void - This word is used for does not return anything.

*Main - This word is used for the Method name entry point.

*String args[] - This word is used for passing arguments through the command line.

Some Rules for making class.

Class names should be nouns.
MIxed case with the first letter of each internal word capitalized.
cannot start with numbers.
No special character allowed except '_' & '$'.

Variables in Java programming language -

Variable is a container which holds a value. Variable assigned with a data type.

Its name for a memory location.

There are three types of variables.

Local Variable: variable declared inside a method. We can use only inside the method. Class not aware of any variable scope inside a method. A local variable can not be defined with a Static keyword.
Instance variable: variable declared inside a class. not declare as static. Each instantiated object of the class has a separate copy.
Static Variable: Variable declared as static is called a static variable.IT can't be local. Create a single copy and share with all instance of a class.

*Declare a variable -

data_type_name = Value;

Ex - int x = 10;

double y = 22.3;

*Naming Convention -

No space to allowed in a variable name.

Can not start with '$' and other '_' symbol not allowed.

Variable name starts with a small letter it's not mandatory its for lengthy variables names that have more than one word do it like the following.

"int first number = 10;"

In java everything case sensitive [keywords and name].

*Data Types -

Data types are the value that can be used in Variable each type Has a different size.

there are 2 types of them.

1.Primitive Data type

2.Non-Primitive Data Type

*Operators -

*Keywords -

There is a '51' reserved word in a JAVA Programming language, which means '51' predefined meaning words present in JAVA. In Java programming language these keywords did not use for other purposes.

JAVA Control Statement -

If statement:

There are multiple 'If' condition.

'If' the condition is true then do it and condition is not true then don't do it.

Nested If Statement :

So I have a condition, the condition is true am going inside and one more 'If' condition So that It is called a Nested If condition.

If-else Statement :

So you go and check a condition if in case the condition is true the executing a block in case condition is not true that means it going to lose block.

If-else-If Statement:

A few steps of the 'if-else-if' condition if some condition or else go-to another condition.

Switch Case Introduction -

Switch case is mostly used with break statements even those it's optional.

When we have a number of options and a number of choices and we might need to perform different tasks for each choice.

Each case statement can have a break statement in order to stop the flow, else all of them will be executed.

Duplicate case values are not allowed.

Values for a case must be the same type as the switch.

Array Introduction -

The array is used to store multiple values in a single variable instead of declaring separate variables for each value.

To initiate an array define the variable type with[] square brackets.

Access the elements using the index numbers.

Looping Concepts -

For Loop:

For loop is used to integrate a part of code several times.

In case if the number of iteration is fixed, it is better choices to use for loop.

We have three types of 'For' loops.

For loop

For each

Labeled for loop

While loop:

While loop is used to integrate a part of the program several times for loop.

But we will not have the iteration fixed.

While condition verified then it will go inside the loop.

Increment/Decrement happens inside while loop

Do-While loop:

Similar to while, used to iterate a part of code several times, Again we will not have the fixed value for the limit.

But at least once loop will run.

Because this one executes the code then evaluates the condition.

Break and Continue Statement -

Break statement :

The break is used to come out of the loop instantly.

Whenever break encounter in a loop, control directly come out of loop gets terminated

The break statement is used to break the loop or switch statement.
Break the current flow.

Continue statement :

It used to loop when you need to jump to the next iteration immediately.

Can be used in for, while and do-while loop.

Comment in Java -

The data which we provided inside the comments we will not use the comments we will not take for compilation.

It used to tell the compiler not the use the commented lines.

We can use to provide some additional information or explanation forex class method and variables.

Types of Comments:

Single line method: The single line comment is used to comment on only one line.

Multi-line method: The multiline comment is used to comment multiline of code.

Documentation: The documentation comment is used to create document API, you need to use java document tool.

String (It belongs to class) -

It is a sequence of characters.

The string is an immutable object which means, its constant and cannot be changed once it has been created.

There are multiple ways to create a String.

String level
Using a new keyword

Java string class provides a lot of methods of performing operations such as compare, concatenation, equals, split, and length.

A Way to create a String -

Learn More :

Technical Things