What is pattern matching and what are its advantages and disadvantages?

Pattern matching is a mechanism that allows checking the structure of data and extracting values from it by comparing with specified templates.

Advantages:

• Enables writing more expressive and readable code.
• Simplifies processing of complex data structures, such as trees or variants.
• Reduces the number of nested conditional operators.

Disadvantages:

• May be less obvious for developers unfamiliar with the concept.
• In some languages, support is limited or absent, requiring additional libraries or patterns.

In Java, pattern matching is gradually being introduced (for example, in newer versions for instanceof), which simplifies type checking and value extraction:

if (obj instanceof String s) {
    System.out.println("String of length " + s.length());
}

Here, instanceof not only checks the type but also immediately assigns the variable s.