Before Java 8, the only way to partially support closures in Java was by using anonymous inner classes. Java 8 introduced lambdas, which are
significantly more readable and should be used instead.
This rule is automatically disabled when the project’s sonar.java.source is lower than 8, as lambda expressions were
introduced in Java 8.
Code examples
Noncompliant code example
myCollection.stream().map(new Function<String,String>() { // Noncompliant, use a lambda expression instead
@Override
public String apply(String input) {
return new StringBuilder(input).reverse().toString();
}
})
...
Compliant solution
myCollection.stream()
.map(input -> new StringBuilder(input).reverse().toString()) // Compliant
...
Noncompliant code example
Predicate<String> isEmpty = new Predicate<String>() { // Noncompliant, use a lambda expression instead
@Override
public boolean test(String myString) {
return myString.isEmpty();
}
};
Compliant solution
Predicate<String> isEmpty = myString -> myString.isEmpty(); // Compliant
