Recent Java versions added a cluster of related features that make modelling data and branching on its shape dramatically more concise and safe. Records are a compact way to declare immutable data-carrier classes: one line gives you the fields, constructor, accessors, equals, hashCode, and toString. Sealed classes and interfaces let a type restrict which classes may extend or implement it, making a type hierarchy a known, closed set.
Pattern matching ties these together: it lets you test an object's type and deconstruct it in one step, in instanceof and especially in switch expressions, matching on types and even on the components of records. Combined, sealed types plus record patterns in a switch give exhaustive, readable handling of a closed set of shapes, the kind of algebraic data modelling that previously required verbose boilerplate or unsafe casting.
Understanding these features matters because they represent the modern idiom for data-centric Java: records eliminate the tedious, error-prone boilerplate of value classes, sealed types make hierarchies explicit and checkable, and pattern matching replaces long chains of instanceof-and-cast with clear, exhaustive branching. Together they let you express 'this data has one of these shapes, and here is what to do for each' directly and safely, which is increasingly how idiomatic Java is written.