Class UnnamedPatternsVariablesPreviewExamples

java.lang.Object

net.jrodolfo.java_evolution.java21.UnnamedPatternsVariablesPreviewExamples

public class UnnamedPatternsVariablesPreviewExamples
extends Object

Demonstrates unnamed patterns and variables as a Java 21 preview feature.

Sometimes Java syntax requires a variable name even though the program intentionally ignores the value. Before this feature, developers often used names such as ignored or unused. The underscore makes that intent part of the language.

The feature became final in Java 22 as unnamed variables and patterns. This example uses JDK 25-compatible syntax.

Constructor Summary

Constructors

Constructor	Description
UnnamedPatternsVariablesPreviewExamples()

Method Summary

Modifier and Type	Method	Description
boolean	canParseInteger(String text)	Uses an unnamed catch parameter when the exception object is not needed.
int	countWithoutUsingElements(Iterable<String> values)	Uses an unnamed variable where the value is intentionally ignored.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

UnnamedPatternsVariablesPreviewExamples

public UnnamedPatternsVariablesPreviewExamples()

Method Details

countWithoutUsingElements

public int countWithoutUsingElements(Iterable<String> values)

Uses an unnamed variable where the value is intentionally ignored.

Parameters:

values - values to count

Returns:

how many values were visited

canParseInteger

public boolean canParseInteger(String text)

Uses an unnamed catch parameter when the exception object is not needed.

Parameters:

text - numeric text

Returns:

whether the text can be parsed