Add a private constructor to hide the implicit public one. Open
final static class FirestoreAdapterFactory {
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Utility classes, which are collections of static
members, are not meant to be instantiated. Even abstract utility classes, which can
be extended, should not have public constructors.
Java adds an implicit public constructor to every class which does not define at least one explicitly. Hence, at least one non-public constructor should be defined.
Noncompliant Code Example
class StringUtils { // Noncompliant public static String concatenate(String s1, String s2) { return s1 + s2; } }
Compliant Solution
class StringUtils { // Compliant private StringUtils() { throw new IllegalStateException("Utility class"); } public static String concatenate(String s1, String s2) { return s1 + s2; } }
Exceptions
When class contains public static void main(String[] args)
method it is not considered as utility class and will be ignored by this
rule.
'static' modifier out of order with the JLS suggestions. Open
final static class FirestoreAdapterFactory {
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Checks that the order of modifiers conforms to the suggestions inthe JavaLanguage specification, ยง 8.1.1, 8.3.1, 8.4.3 and9.4. The correct order is:
public
protected
private
abstract
default
static
final
transient
volatile
synchronized
native
strictfp
In additional, modifiers are checked to ensure all annotations aredeclared before all other modifiers.
Rationale: Code is easier to read if everybody follows a standard.
ATTENTION: We skiptype annotations from validation.
This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.