Java Collections.unmodifiableList() is a static method in the Java Collections class that returns an unmodifiable view of the specified list. It prevents modification of the original list by throwing an Java UnsupportedOperationException if any modification methods are called. Introduced in Java 1997 with Java 1.2, unmodifiableList() is commonly used in situations where data integrity is crucial and modifications to a list should be prevented.

https://docs.oracle.com/javase/8/docs/api/java/util/Collections.html