Exception Handling
Checked vs unchecked, try-with-resources, custom exceptions, finally, suppressed exceptions, propagation, overriding rules, best practices and Spring Boot error handling.
Exception Handling Fundamentals
What exceptions are, Error vs Exception, the Throwable hierarchy, stack traces, propagation and the five keywords.
Checked vs Unchecked Exceptions
Compile-time vs runtime checking, why checked exceptions exist, throws, overriding rules and the Spring Boot preference.
try-with-resources
Automatic resource management since Java 7 — AutoCloseable vs Closeable, multiple resources, LIFO closing and the Java 9 form.
Custom Exceptions
Designing meaningful domain exceptions — checked vs unchecked, constructors, exception chaining and Spring Boot handling.
Exception Hierarchy
The full Throwable tree, Error vs Exception vs RuntimeException, catch matching and ordering, polymorphism and multi-catch.
finally Block
Cleanup that always runs — execution order, when finally doesn't run, return and exceptions inside finally, and output-based traps.
Suppressed Exceptions
How try-with-resources keeps the primary exception and attaches cleanup failures — addSuppressed, getSuppressed and cause vs suppressed.
throw vs throws
Throwing vs declaring — JVM behaviour, checked/unchecked rules, re-throwing and wrapping, throw null, constructors and overriding.
Exception Propagation & Stack Unwinding
How exceptions travel up the call stack, how the JVM unwinds frames, checked vs unchecked propagation and translation across Spring layers.
Exception Overriding Rules
Same, narrower or none — never broader. Checked vs unchecked rules for overriding, interfaces, abstract classes and constructors.
Best Practices & Anti-Patterns
Production-ready exception handling — what to catch, where to log, translation, fail-fast, performance and the senior developer checklist.
Exception Handling in Spring Boot
@ExceptionHandler, @ControllerAdvice, custom error bodies, validation errors, ProblemDetail and mapping exceptions to HTTP status codes.