Optional chaining

Replace nested null checks with an Optional pipeline.

Code Comparison

✕ Java 8

String city = null;
if (user != null) {
    Address addr = user.getAddress();
    if (addr != null) {
        city = addr.getCity();
    }
}
if (city == null) city = "Unknown";

✓ Java 9+

String city = Optional.ofNullable(user)
    .map(User::address)
    .map(Address::city)
    .orElse("Unknown");

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Why the modern way wins

🔗

Chainable

Each .map() step handles null transparently.

📖

Linear flow

Read left-to-right instead of nested if-blocks.

🛡️

NPE-proof

null is handled at each step — no crash possible.

Old Approach

Nested Null Checks

Modern Approach

Optional Pipeline

Since JDK

Difficulty

Beginner

JDK Support

Optional chaining

Available

Available since JDK 8+ (improved in 9+)

How it works

Optional.map() chains through nullable values, short-circuiting on the first null. orElse() provides the default. This eliminates pyramid-of-doom null checking.

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

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+ →

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+ →