liquibase-core/src/main/java/liquibase/util/Validate.java
public static void notNull(Object object, String failMessage) throws UnexpectedLiquibaseException {
        if (object == null) {
            fail(failMessage);
        }
    }
public static void notNull(Object object, String failMessage) throws UnexpectedLiquibaseException {
        if (object == null) {
            fail(failMessage);
        }
    }
Throws exception if passed object is null