🔸 TL;DR
▪️ Keep a clear file header, then package, then import.
▪️ Split the file into sections with blank lines; avoid files > 2000 lines.
▪️ Inside classes: doc comment → declaration → optional impl comment → class (static) vars (public→protected→private) → instance vars (public→protected→private) → constructors → methods (grouped by functionality, not visibility).
🔸 FILE ORGANIZATION (TOP TO BOTTOM)
▪️ Beginning comments: a short, purposeful file header (copyright, license, brief intent).
▪️ Package statement: exactly one, first code statement.
▪️ Import statements: follow the package; group logically and separate groups with blank lines.
▪️ Sectioning: split the file into meaningful sections using blank lines (+ optional section comments).
▪️ Size: files longer than 2000 lines are cumbersome—prefer splitting/refactoring.
🔸 INSIDE A CLASS/INTERFACE: RECOMMENDED ORDER
▪️ 1) Documentation comment (/** ... */) — what/why, references.
▪️ 2) Class or interface statement — public class … / interface ….
▪️ 3) Implementation comment (/* ... */, optional) — class-wide notes not suited to Javadoc.
▪️ 4) Class (static) variables — order: public → protected → private.
▪️ 5) Instance variables — order: public → protected → private.
▪️ 6) Constructors — group by purpose/overload families.
▪️ 7) Methods — group by functionality, not visibility; a private helper can sit between two public methods if it improves readability.
🔸 NAMING & PATH (RECAP)
▪️ Filename = public top-level type + .java (e.g., OrderService.java).
▪️ Directory path mirrors the package (e.g., com.acme.billing → .../com/acme/billing/OrderService.java).
▪️ One public top-level type per file; let tests mirror names (e.g., OrderServiceTest.java).
🔸 TAKEAWAYS
▪️ Start clean: header → package → imports; then well-sectioned code.
▪️ Order inside classes matters—it speeds up comprehension and reviews.
▪️ Keep files focused and small; refactor when size or responsibilities grow.
#Java #CleanCode #CodeConventions #Readability #SoftwareCraftsmanship #Maintainability #BestPractices
Java Code Conventions by Oracle: https://www.oracle.com/docs/tech/java/codeconventions.pdf
Go further with Java certification:
Java👇
Spring👇
SpringBook👇