Why there are so many assertAll methods in Junit class AssertAll? What is the use of each.

class AssertAll {

    private AssertAll() {
        /* no-op */
    }

    static void assertAll(Executable... executables) {
        assertAll(null, executables);
    }

    static void assertAll(String heading, Executable... executables) {
        Preconditions.notEmpty(executables, "executables array must not be null or empty");
        Preconditions.containsNoNullElements(executables, "individual executables must not be null");
        assertAll(heading, Arrays.stream(executables));
    }

    static void assertAll(Collection<Executable> executables) {
        assertAll(null, executables);
    }

    static void assertAll(String heading, Collection<Executable> executables) {
        Preconditions.notNull(executables, "executables collection must not be null");
        Preconditions.containsNoNullElements(executables, "individual executables must not be null");
        assertAll(heading, executables.stream());
    }

    static void assertAll(Stream<Executable> executables) {
        assertAll(null, executables);
    }

    static void assertAll(String heading, Stream<Executable> executables) {
        Preconditions.notNull(executables, "executables stream must not be null");

        List<Throwable> failures = executables //
                .map(executable -> {
                    Preconditions.notNull(executable, "individual executables must not be null");
                    try {
                        executable.execute();
                        return null;
                    }
                    catch (Throwable t) {
                        UnrecoverableExceptions.rethrowIfUnrecoverable(t);
                        return t;
                    }
                }) //
                .filter(Objects::nonNull) //
                .collect(Collectors.toList());

        if (!failures.isEmpty()) {
            MultipleFailuresError multipleFailuresError = new MultipleFailuresError(heading, failures);
            failures.forEach(multipleFailuresError::addSuppressed);
            throw multipleFailuresError;
        }
    }

}

Comments

[Kasid Khan]

Found the answer.
assertAll(Executable... executables) is calling assertAll(null,Executable... executables)
assertAll(null,Executable... executables) is calling assertAll(String heading, Stream executables), which is the actual method that does the execution.

assertAll(null,Executable... executables) == assertAll(heading,Executable... executables)
pheww !!