如何配置IntelliJ IDEA，在Lombok生成构造器违反@NotNull/@Nullable契约时告警？

Got it, let's sort out why IntelliJ isn't flagging null violations for your Lombok-generated constructors—even though you've set lombok.NonNull as your @NotNull annotation and already get alerts for getters/setters. Here's the step-by-step fix:

1. Verify Annotation Processing is Enabled #

First, make sure IntelliJ is properly handling Lombok annotations (this is a common overlooked step):

• Go to Settings > Build, Execution, Deployment > Compiler > Annotation Processors
• Check the box for Enable annotation processing
• If you use Maven/Gradle, ensure your build tool is configured to work with IntelliJ's annotation processor (this ensures IDE picks up Lombok-generated code correctly)

2. Turn On Constructor Parameter Checks in Inspections #

This is almost certainly the missing piece—you need to explicitly tell IntelliJ to validate constructor parameters for @NotNull violations:

• Navigate back to Settings > Editor > Inspections > Java > Probable bugs > @NotNull/@Nullable problems
• On the right-hand panel, scroll through the options and make sure Check constructor parameters is checked (it might be disabled by default)
• Double-check your annotation mapping here too: click Configure annotations, confirm lombok.NonNull is set as your @NotNull annotation, and that it's mapped for both fields and method/constructor parameters

3. Refresh IntelliJ's Cache #

Sometimes old cache data blocks new settings from taking effect:

• Go to File > Invalidate Caches...
• Select Invalidate and Restart from the popup—this clears stale cached data and restarts the IDE to apply your changes

Test the Fix #

To confirm everything works, create a quick test class:

import lombok.NonNull;
import lombok.RequiredArgsConstructor;

@RequiredArgsConstructor
public class TestConstructorNullCheck {
    @NonNull private final String username;

    public static void main(String[] args) {
        // This line should now trigger a @NotNull violation alert
        TestConstructorNullCheck test = new TestConstructorNullCheck(null);
    }
}

If all settings are correct, the null passed to the constructor will be highlighted with a warning about violating the @NonNull contract.

内容的提问来源于stack exchange，提问作者Eric