Hello world!

<Access_Modifier> class <Class_Name> extends <Super_Class_Name> implements <Interface_Name>{
    <static initilizar block>
    <ananymous_block>
    <constructor_declarations>
    <field_declarations (Static or Non-Static)>
    <method_declarations (Static or Non-Static)>
    <Inner_class_declarations>
    <nested_interface_declarations>
    variables_inside_class(Static or Non Static)
}

Class is a template for creating objects which defines its <Inner_class_declarations> state and behavior. A class contains field and method to define the state and behavior of its object.