J.SOLID Principle

It is an acronym for collection of group of most commonly used principle 
SSRP
Single responsibility principle
class should have only a single responsibility.
OOCP
Open/closed principle
“software entities … should be open for extension, but closed for modification”.
LLSP
Liskov substitution principle
“objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program”. See also design by contract.
IISP
Interface segregation principle
“many client-specific interfaces are better than one general-purpose interface.”[5]
DDIP
Dependency inversion principle
one should “Depend upon Abstractions. Do not depend upon concretions.”[5]
Dependency injection is one method of following this principle.