Eliminate Excessive Null Checks: Cleaner Java Code Without try‑catch

Problem

To avoid NullPointerException, developers often write explicit null‑check statements like if (someObject != null) { someObject.doCalc(); }, which leads to repetitive and ugly code.

Key Answer

The issue stems from two situations:

When null is an invalid response and should cause an error (e.g., missing required API parameter). Use assert or throw an exception instead of silent checks.

When null is a valid “empty” result (e.g., no data found). Return empty collections or a Null Object instead of null.

Practical Advice

1. For methods returning collections, return Collections.emptyList() (or similar) rather than null, allowing callers to use the result without extra checks.

2. For non‑collection return types, return a harmless default object. Example using the Null Object pattern:

public interface Action {
    void doSomething();
}
public interface Parser {
    Action findAction(String userInput);
}
public class MyParser implements Parser {
    private static final Action DO_NOTHING = new Action() {
        public void doSomething() { /* do nothing */ }
    };
    public Action findAction(String userInput) {
        // …
        if (/* cannot find any actions */) {
            return DO_NOTHING;
        }
        // …
    }
}

With this approach, callers can safely invoke findAction(...).doSomething() without null checks.

Other Helpful Tips

Prefer "constant".equals(variable) to avoid NullPointerException.

Java 8’s Optional or Guava’s Optional can encapsulate possible null values.

If a method might return null, consider throwing an exception instead.