Master Java's Optional class from the ground up. This series covers everything from creating Optional instances to advanced patterns and common pitfalls. You'll learn to eliminate NullPointerException errors, write cleaner functional-style code, and understand why certain Optional patterns are considered anti-patterns in production codebases.

• Java Optional: Complete Guide with Examples
• Java Optional of() vs ofNullable() vs empty(): Which to Use?
• Java Optional orElse vs orElseGet: Performance Differences
• Java Optional orElseThrow(): Throwing Custom Exceptions
• Java map() vs flatMap()
• Java Optional filter() Method with Real-World Examples
• Java Optional isPresent() vs isEmpty(): Complete Guide
• Java Optional ifPresentOrElse()
• Java Optional as Field: Why It's an Anti-Pattern

You should be comfortable with basic Java syntax, lambda expressions, and understand what NullPointerException is and why it happens.

Optional was introduced in Java 8. Most methods covered in this series work with Java 8, but isEmpty() requires Java 11 and ifPresentOrElse() requires Java 9.

No. Use Optional for method return types where absence is a valid, expected outcome. Don't use it for fields, method parameters, or collections.

orElse() always evaluates its argument, even when the Optional contains a value. orElseGet() only calls its supplier when needed. This matters when the default value is expensive to create.

Optional is not serializable, adds memory overhead per instance, and breaks compatibility with JPA, Hibernate, and most Java frameworks. Store nullable fields and return Optional from getters instead.

map() transforms the value inside an Optional and wraps the result in a new Optional. flatMap() is for when your transformation already returns an Optional, avoiding nested Optional<Optional<T>>.