Unnamed variables with _

Code Comparison

try {
    parse(input);
} catch (Exception ignored) {
    log("parse failed");
}
map.forEach((key, value) -> {
    process(value); // key unused
});

try {
    parse(input);
} catch (Exception _) {
    log("parse failed");
}
map.forEach((_, value) -> {
    process(value);
});

Why the modern way wins

📢

Clear intent

_ explicitly says 'this value is not needed here'.

🔇

No warnings

IDEs and linters won't flag intentionally unused variables.

🧹

Cleaner lambdas

Multi-param lambdas are cleaner when you only need some params.

Old Approach

Unused Variable

Modern Approach

_ Placeholder

JDK Support

Unnamed variables with _

Available

Finalized in JDK 22 (JEP 456, March 2024).

How it works

Unnamed variables communicate to readers and tools that a value is deliberately ignored. No more 'ignored' or 'unused' naming conventions, no more IDE warnings.