LLD

1. UML DIAGRAM.

UML diagram is way to expess how application work what are entity of application and they intract with each other.

Types of UML DIAGRAM.

1. Structual(Static): Explain structure of application/object/class. and how they are link with each other.
2. Behaviour(Dynamic): How object are intract with each other.

Note: We have to study Class Diagram and Sequence Diagram.

Class Diagram.

1. Class structure
2. Assoication/Connection

Assoiciation

A. Inheritance: is-a relation

B. Composition: has-a relation. (most used)

Example:

class A { 
    method1(); 
} 
class B { 
    A a; 
    B() { a = new A(); }
    method2(); 
} 

main { 
    B b = new B(); 
    b.method2(); 
    b.a.method1();
}

Sequence Diagram

to coming...

SOLID PRINCIPLE

What problem arises. when thoused of classes create in Application then these problem occurse.

• Maintainbility
• Readbility
• BUGS