Java Program to Compare Two Objects Difficulty Level : Medium Last Updated : 16 Jun, 2021 Read Discuss Courses Practice Video An object is an instance of a class that has its state and behavior. A variety of data analysis methods (i.e., descriptive statistics, hypothesis testing, correlation analysis, multidimensional scaling, cluster analysis, and trend analysis) were used to answer the research questions, which allowed us to evaluate and compare the consistency of several variants of the Index in measuring the maintainability of object-oriented software systems on a large and diverse set of Java software in different contexts. All source codes for the included software systems were obtained from the original (i.e., not forked) GitHub repositories. 2021. Sawilowsky, S.S. New effect size rules of thumb. JHawk. This interface is present in java.util package and contains 2 methods compare(Object obj1, Object obj2) and equals(Object element). A Computer Science portal for geeks. ; Motogna, S. A Study of Maintainability in Evolving Open-Source Software. Note: For BeanComparator, commons-collection and commons-logging jar files need to be . It uses this result to then determine if they should be swapped for their sort. Identity of references The comparison operator == has long been known when dealing with primitive data types. In Proceedings of the 2015 41st Euromicro Conference on Software Engineering and Advanced Applications, Madeira, Portugal, 2628 August 2015; pp. By using this website, you agree with our Cookies Policy. Keep reading to see how hard it is and how you can take advantage of it to improve your coding skills. The Maintainability Index variants were computed from software metrics extracted from the code of each system by the JHawk tool. 486492. Determ. You seem to have javascript disabled. Kaur and Singh [, Although there are some similarities with the existing work, the lack of a comprehensive approach to comparing multiple variations of the Index makes our work the first of its kind in the field. By changing the return value inside the compare method, you can sort in any order that you wish to, for example: For descending order just change the positions of a and b in the above compare method. 1) By Using equals () Method The String class equals () method compares the original content of the string. This article is contributed by Rishabh Mahrsee. ; Papesh, M.H. permission provided that the original article is clearly cited. = standard deviation, Min. When comparing the maintainability of different versions of the same software using different Index variants, the relationship between the variants remains positive, but can range from moderate to very strong. Java provides different methods you can leverage to compare two strings in Java. Questioning software maintenance metrics: A comparative case study. person1 and person2 have the same properties with the same values. In the second comparison, equals () checks to see whether the passed object is null, or if it's typed as a different. The correctness and completeness of this process were manually verified on a sample of subjects. Sjberg, D.I.K. ; project administration, B.. Correlation coefficients: Appropriate use and interpretation. Mastering JS. ; Oman, P.W. 101108. If the properties are objects, you take advantage of the recursion to keep going until the properties are primitive type. Well, its easy for the primitive types, not for the objects. 568573. Heriko, T.; umak, B. The differences in Index variants values are the most notable when looking at the finer-grained results derived from different Index variants. 759768. A total of 45 object-oriented software systems were randomly selected for the study. I propose another option one that could be useful , especially when theres a need to compare different properties in different tests. In, To assess the relationship between Index variants in the context of comparing the maintainability of versions of the same software system, a correlation analysis was conducted for each case study. There are several Index variants that differ in the factors affecting maintainability (e.g., code complexity, software size, documentation) and their given importance. Mark X is used to indicate the inclusion of a software metric for the computation of a specific Index variant. To perform the comparison of objects, we have created a separate class named HashCodeExample. and B.. We can, therefore, compare them: assertThat (planes1).isNotSameAs (planes2); To sum up, in this case, we have two arrays in memory that contain the same String values in exactly the same order. In Proceedings of the International Conference on Contemporary Computing, Noida, India, 1719 August 2009; Springer: Berlin/Heidelberg, Germany, 2009; pp. 2021. In Proceedings of the 2009 3rd International Symposium on Empirical Software Engineering and Measurement, Lake Buena Vista, FL, USA, 1516 October 2009; pp. https://doi.org/10.3390/app13052972, Heriko T, umak B. Object-oriented programming paradigm for damage tolerant evaluation of engineering structural components. Agree Method 1: One obvious approach is to write our own sort() function using one of the standard algorithms. Dubey, S.K. In this way, many comparisons between two objects need not go through the comparison of every value within them. If a class implements Comparable then such comparator may be used in compareTo method: @Override public int compareTo (Person o) { return Comparator.comparing (Person::getFirstName) .thenComparing (Person::getLastName) .thenComparingInt (Person::getAge) .compare (this, o); } Share Improve this answer edited Aug 8, 2017 at 15:28 community wiki Java Program to Compare two Boolean Arrays, Java Program to Compare two Double Arrays, Compare two strings lexicographically in Java, equals() and deepEquals() Method to Compare two Arrays in Java. Java provides the two methods of the Object class to compare the objects are as follows: Java equals () Method Java hashCode () Method Java equals () Method The equals () method of the Object class compare the equality of two objects. Compare Two Employee Objects in java In the below program, Created two Employee objects with different values. In Proceedings of the 1st International Workshop on Distributed Objects for the 21st Century, Genova, Italy, 610 July 2009; Association for Computing Machinery: New York, NY, USA, 2009. Development and Application of an Automated Source Code Maintainability Index. To answer RQ1 and RQ2.1, the most recently released version at the time of conducting the experiments for each of the 45 software systems under study was used. ; writingoriginal draft preparation, T.H. The object-oriented paradigm is one of the dominant programming paradigms for modeling and developing software. ; Pant, B.; Tiwari, U.K. Wilson, A.; Wedyan, F.; Omari, S. An Empirical Evaluation and Comparison of the Impact of MVVM and MVC GUI Driven Application Architectures on Maintainability and Testability. Visit our dedicated information section to learn more about MDPI. For example, if code documentation significantly benefits software maintainability, a variant incorporating code comments into the Index computation should be used. Ganpati, A.; Kalia, A.; Singh, H. A comparative study of maintainability index of open source software. We can compare two HashMap by comparing Entry with the equals () method of the Map returns true if the maps have the same key-value pairs that mean the same Entry. [. Kaur, L.; Mishra, A. 235239. Therefore, extra caution should be taken when using the Index variants for more specific assessments instead of general ones. Ignoring which Index variant is used to assess maintainability could lead to misleading perceptions. Microsoft. Comparing Maintainability Index, SIG Method, and SQALE for Technical Debt Identification. Most of the time, we want to compare the actual values inside the objects. Rather, it's their memory addresses in the stack that are different, since both objects are created using the new operator. After that, in the first println statement, we have invoked equals() method and parse an object y as a parameter that compares the object x and y. In this article, You've seen how to compare two objects in java using equals() method of Object class. The following abbreviations are used in this manuscript: Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. Illustration: An example to illustrate an object of a class: // Here, chair and sofa are two objects of the class Furniture. If you are not calling the Collections.sort() method then our comparator logic will not be executed. It can be observed that, in the case when comparing the maintainability between releases of the same software system, i.e., when changes in the source code are small, the Index variants tend to be more prone to non-consistency in the maintainability comparisons. The 2021 State of the Octoverse. However, not only are the referenced arrays different in content, but the references themselves are also different. let us create a new Employee e3 object with the same values as e1. In the following example, we have created constructor of the Double and Long class and passes corresponding values, as an argument that stored in their objects, respectively. The two objects will be equal if they share the same memory address. = average, Med. [, Counsell, S.; Liu, X.; Eldh, S.; Tonelli, R.; Marchesi, M.; Concas, G.; Murgia, A. Re-visiting the Maintainability Index Metric from an Object-Oriented Perspective. However, we've used String constructor to create the strings. Papamichail, M.D. equals() and hashCode() method. Although numerous measures have been proposed in the literature for assessing software quality factors, few studies have focused on comparing the Index with other maintainability or software quality measures. Gradinik, M.; Berani, T.; Karakati, S. Impact of historical software metric changes in predicting future maintainability trends in open-source software development. [, Heriko, T.; umak, B. Analyzing Linter Usage and Warnings Through Mining Software Repositories: A Longitudinal Case Study of JavaScript Packages. Learn to code interactively with step-by-step guidance. The only difference is in person1, the property age appears before name, meanwhile, in person2, name comes before age. The objective was to determine if and to what degree these variants are consistent with one another when used to assess the maintainability of a single software system and when used to compare the maintainability of different software systems. Note: For BeanComparator, commons-collection and commons-logging jar files need to be included. Author to whom correspondence should be addressed. We simply use the equal to operator (==) to compare the two strings, which compares the value Bold to Bold and prints Equal. ; formal analysis, T.H. Java Object class is the super class of all the Java classes. As an example, you have a List of Employee Objects and you need to check that all your Employees are above 18. If you instead change the program to use equality operator, you'll get Not Equal as shown in the program below. A Feature Below are 5 ways to compare two Strings in Java: Using user-defined function : Define a function to compare values with following conditions : if (string1 > string2) it returns a positive value. Though, when focusing on fine-grained results posed by the Index, the variant selection had a larger impact. A Tale of Two Development Approach: Empirical Study on The Maintainability and Modularity of Android Mobile Application with Anti-Pattern and Model-View-Presenter Design Pattern. 252264. One major threat to external validity is related to the software systems on which the research is based, including sample size, selection bias, and subject characteristics. Join our newsletter for the latest updates. When comparing two software systems based on their maintainability assessments from different Index variants, if one software is easier to maintain than the other according to one variant, it is very likely that the same holds true according to any other variant. Java 8 - Comparison with Lambdas and example on Java 8 Comparator.comparing(). Singh, N.; Singh, D.P. In the following example, we have created two classes Employee.java and HashCodeExample.java. Brito e Abreu, F.; Melo, W. Evaluating the impact of object-oriented design on software quality. Now, you will write a function to compare two objects. Applied Sciences. Future efforts could also be invested in investigating and determining the Index threshold levels for object-oriented software. Appl. Each Java object is associated with the hash code. The equals () method is used to compare objects according to their content. In Proceedings of the Software Engineering Productivity Conference, Salt Lake City, UT, USA, 7 April 1992; pp. However, it can be overridden in any way possible i.e if one or two values match, etc. By using our site, you [. Note that some human analysis of the comments is recommended to aid this decision [. JavaTpoint offers college campus training on Core Java, Advance Java, .Net, Android, Hadoop, PHP, Web Technology and Python. A comparator interface is used to order the objects of user-defined classes. ; investigation, T.H. Then, we will compare the objects by using the BeanComparator by calling its compare () method. Comparative Analysis of Object-Oriented Software Maintainability Prediction Models. = average, Med. = minimum, Max. Several aspects can impact the softwares maintainability, including the codes complexity, the softwares size, and the presence of documentation and comments that help describe the code. ; Rachmadi, R.R. In short, for any non-null reference say x and y, it returns true if and only if both references refer to the same object. In Proceedings of the 27th International Workshop on Software Measurement and 12th International Conference on Software Process and Product Measurement, Gothenburg, Sweden, 2527 October 2017; Association for Computing Machinery: New York, NY, USA, 2017; pp.