Describe the new features introduced in Java versions 15 and 17

In Java 15 and Java 17, several important features and improvements were introduced:

Java 15:

• Records (preview) — a compact way to define immutable classes with automatic generation of equals(), hashCode(), and toString() methods.
• Sealed Classes (preview) — allow restricting the inheritance hierarchy by specifying which classes can extend a given class.
• Text Blocks — multi-line string literals that simplify working with multi-line text.
• Improvements in Garbage Collector (e.g., ZGC became more performant).

Java 17 (LTS):

• Sealed Classes (stable) — final introduction of sealed classes.
• Pattern Matching for instanceof — simplifies type checking and casting.
• Strongly Encapsulate JDK Internals — enhanced encapsulation of internal APIs.
• Performance and security improvements.

Example of using Records (Java 16+):

public record Point(int x, int y) {}

Point p = new Point(1, 2);
System.out.println(p.x()); // 1

This allows quickly creating classes with immutable fields without extra boilerplate code.