The problem

RecordAccessorInCompactConstructor

Summary: Record accessors should not be used inside compact constructors because they read uninitialized fields.

The Problem

In a Java record, using the accessor method (like d()) inside a compact constructor (the one without arguments, Foo { ... }) reads the record’s underlying field before it has been set. This means the method will always return null (for objects) or 0/false (for primitives), regardless of what arguments were passed to the constructor.

Examples

Bad: Using the accessor method

record User(String name) {
  User {
    // BUG: name() reads the uninitialized field 'this.name', which is currently
    // null. This throws a NullPointerException immediately.
    if (name().isEmpty()) {
      throw new IllegalArgumentException("Name cannot be empty");
    }
  }
}

Good: Using the parameter name directly

record User(String name) {
  User {
    // CORRECT: Reads the constructor parameter 'name'.
    if (name.isEmpty()) {
      throw new IllegalArgumentException("Name cannot be empty");
    }
  }
}

Explanation

The Compact Constructor in Java is a special initialization block that runs before the record’s fields are automatically assigned.

1. Code Execution: The code inside your compact constructor User { ... } runs first.
2. Field Assignment: The compiler automatically assigns the parameters to the fields (this.name = name;) only after your code block finishes (JLS §8.10.4.2).

When you call name(), it attempts to read this.name. Since the assignment hasn’t happened yet, this.name still holds its default value, which is null (JLS §4.12.5).

To fix this, refer to the component by its name (e.g., name). This accesses the parameter passed to the constructor, which holds the correct value.

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("RecordAccessorInCompactConstructor") to the enclosing code.

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("RecordAccessorInCompactConstructor") to the enclosing element.