HighFile-scopeJava Plug & play

Use Java Records for Immutable Data Structures

Ensure that Java records are used for immutable data structures instead of manually implementing immutable classes.

Why this matters

Java records provide built-in immutability, reducing the risk of accidental modifications. Avoid manually creating immutable classes when records can be used.

Bad vs. good

Side-by-side examples engineers can pattern-match during review.

Avoid

final class Person { // Noncompliant
  private final String title;
  private final int age;

  public Person(String title, int age) {
    this.title = title;
    this.age = age;
  }

  public String getName() {...}

  public int getAge() {...}

  @Override
  public boolean equals(Object o) {...}

  @Override
  public int hashCode() {...}

  @Override
  public String toString() {...}
}

Prefer

record Person(String title, int age) { }

More snippets

Bad

final class Person { // Noncompliant
  private final String title;
  private final int age;

  public Person(String title, int age) {
    this.title = title;
    this.age = age;
  }

  public String getName() {...}

  public int getAge() {...}

  @Override
  public boolean equals(Object o) {...}

  @Override
  public int hashCode() {...}

  @Override
  public String toString() {...}
}

Good

record Person(String title, int age) { }

Related rules

From the same buckets as this rule.

Critical
Avoid Duplicating String Literals
Store repeated string literals in constants or variables to improve maintainability and reduce redundancy.
duplication-complexitymaintainability
Critical
Avoid Empty Methods
Detect methods that have an empty body. If a method is empty, ensure that a comment is present explaining why it remains unimplemented.
maintainabilityreadability-refactor
Critical
Avoid modifying built-in prototypes
Detect modifications to built-in prototypes. Modifying built-in objects can lead to compatibility issues and unexpected behavior. Recommend creating helper functions instead.
maintainabilitysecurity-hardening

Bad vs. good

Side-by-side examples engineers can pattern-match during review.

Avoid

final class Person { // Noncompliant
  private final String title;
  private final int age;

  public Person(String title, int age) {
    this.title = title;
    this.age = age;
  }

  public String getName() {...}

  public int getAge() {...}

  @Override
  public boolean equals(Object o) {...}

  @Override
  public int hashCode() {...}

  @Override
  public String toString() {...}
}

Prefer

record Person(String title, int age) { }

More snippets

Bad

final class Person { // Noncompliant
  private final String title;
  private final int age;

  public Person(String title, int age) {
    this.title = title;
    this.age = age;
  }

  public String getName() {...}

  public int getAge() {...}

  @Override
  public boolean equals(Object o) {...}

  @Override
  public int hashCode() {...}

  @Override
  public String toString() {...}
}

Good

record Person(String title, int age) { }

Related rules

From the same buckets as this rule.

Critical

Avoid Duplicating String Literals

Store repeated string literals in constants or variables to improve maintainability and reduce redundancy.

duplication-complexitymaintainability

Critical

Avoid Empty Methods

Detect methods that have an empty body. If a method is empty, ensure that a comment is present explaining why it remains unimplemented.

maintainabilityreadability-refactor

Critical

Avoid modifying built-in prototypes

Detect modifications to built-in prototypes. Modifying built-in objects can lead to compatibility issues and unexpected behavior. Recommend creating helper functions instead.

maintainabilitysecurity-hardening