The advanced software application developed using various programming languages pose great threat to the breach of confidential data if not taken care of. Code smells and Vulnerabilities deals with identifying the lacunae in software during maintenance and after production respectively. Code smells are niggardly practices followed by developers and vulnerabilities are the glitch or flaw in the operating system that pertains to breaching the security measures. The book conceptualises the procedure of code smell and vulnerability detection using different machine learning and deep learning methodologies while predicting the highest accuracy using different tools and methodologies and possible threat to the validity.