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Errors Intermediate

Record-based error responses

Use records for concise, immutable error response types.

Records

Code Comparison

✕ Java 8

// Verbose error class
public class ErrorResponse {
    private final int code;
    private final String message;
    // constructor, getters, equals,
    // hashCode, toString...
}

✓ Java 16+

public record ApiError(
    int code,
    String message,
    Instant timestamp
) {
    public ApiError(int code, String msg) {
        this(code, msg, Instant.now());
    }
}

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Why the modern way wins

📏

Concise

Define error types in 3 lines instead of 30.

🔒

Immutable

Error data can't be accidentally modified after creation.

📋

Auto toString

Perfect for logging — shows all fields automatically.

Old Approach

Map or Verbose Class

Modern Approach

Error Records

Since JDK

Difficulty

Intermediate

JDK Support

Record-based error responses

Available

Widely available since JDK 16 (March 2021)

How it works

Records are perfect for error responses — they're immutable, have built-in equals/hashCode for comparison, and toString for logging. Custom constructors add validation or defaults.

Helpful NullPointerExceptions

Java 8

// Old NPE message:
// "NullPointerException"
// at MyApp.main(MyApp.java:42)
// Which variable was null?!

Java 14+

// Modern NPE message:
// Cannot invoke "String.length()"
// because "user.address().city()"
// is null
// Exact variable identified!

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JDK 14+ →

Errors Beginner

Objects.requireNonNullElse()

Java 8

String name = input != null
    ? input
    : "default";
// easy to get the order wrong

Java 9+

String name = Objects
    .requireNonNullElse(
        input, "default"
    );

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JDK 9+ →

Errors Beginner

Multi-catch exception handling

Pre-Java 7

try {
    process();
} catch (IOException e) {
    log(e);
} catch (SQLException e) {
    log(e);
} catch (ParseException e) {
    log(e);
}

Java 7+

try {
    process();
} catch (IOException
    | SQLException
    | ParseException e) {
    log(e);
}

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JDK 7+ →