Method isArrayJs

java/lib/src/main/java/io/github/ccxt/Helpers.java:245–249

Null-safe Array.isArray equivalent. ast-transpiler emits `(X instanceof List) || (X.getClass().isArray())` for `Array.isArray(X)`, which NPEs when X is null (e.g. test.sharedMethods entryKeyVal coming from safeValue() that returned undefined). JS Array.isArray(null) is false; mirror that here. Used

(Object a)

     * 150+ call sites become null-safe in one place.
     */
    public static boolean isArrayJs(Object a) {
        if (a == null) return false;
        if (a instanceof List<?>) return true;
        return a.getClass().isArray();
    }

    /**
     * Direct emit target for ast-transpiler PR #48: `Array.isArray(x)` now