Non-static initializers are rarely used, and can be confusing for most developers because they only run when new class instances are created. When possible, non-static initializers should be refactored into standard constructors or field initializers.


== Noncompliant Code Example

[source,java]
----
class MyClass {
  private static final Map<String, String> MY_MAP = new HashMap<String, String>() {

    // Noncompliant - HashMap should be extended only to add behavior, not for initialization
    {
      put("a", "b");
    }

  };
}
----


== Compliant Solution

[source,java]
----
class MyClass {
  private static final Map<String, String> MY_MAP = new HashMap<String, String>();

  static {
    MY_MAP.put("a", "b");
  }
}
----
or using Java 9 ``++Map.of++``:

[source,java]
----
class MyClass {
  // Compliant
  private static final Map<String, String> MY_MAP = java.util.Map.of("a", "b");
}
----
or using Guava:

[source,java]
----
class MyClass {
  // Compliant
  private static final Map<String, String> MY_MAP = ImmutableMap.of("a", "b");
}
----



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== Comments And Links
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