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Showing posts with the label object comparison

Java Keywords (Part XVI): The many uses of the super keyword

We are up to 40 keywords covered in previous articles! That's 83% keywords covered. We have only 8 keywords to cover and I will be covering 1 of those in this article. We are almost done with all the basic keywords. This article will illustrate the use of the keyword super . I suggest you start with Java Keywords (Part I) before proceeding further, if you have not read any of the previous articles in the Java Keyword series. Also, go back and read the one about Data Types. All of these articles are from September 2018. That should help you find them quickly. You can also use the "search" option at the top of this page. The series was written with natural progression in mind. Therefore, some of the keywords already covered may be used in code examples illustrated here. Java keyword list abstract continue for new switch assert default goto * package synchronized boolean do if private this break double implements protected throw

Java Keywords (Part XV): The many uses of the this keyword

We are up to 39 keywords covered in previous articles! That's 81% keywords covered. We have only 9 keywords to cover and I will be covering 1 of those in this article. We are almost done with all the basic keywords. This article will illustrate the use of the keyword this . I suggest you start with Java Keywords (Part I) before proceeding further, if you have not read any of the previous articles in the Java Keyword series. Also, go back and read the one about Data Types. All of these articles are from September 2018. That should help you find them quickly. You can also use the "search" option at the top of this page. The series was written with natural progression in mind. Therefore, some of the keywords already covered may be used in code examples illustrated here. Java keyword list abstract continue for new switch assert default goto * package synchronized boolean do if private this break double implements protected throw

Java Keywords (Part XIV): Using the instanceof Operator

We are up to 38 keywords covered in previous articles! That's 79% keywords covered. We have only 10 keywords to cover and I will be covering 1 of those in this article. We are almost done with all the basic keywords. This article will illustrate the use of the keyword instanceof . I suggest you start with Java Keywords (Part I) before proceeding further, if you have not read any of the previous articles in the Java Keyword series. Also, go back and read the one about Data Types. All of these articles are from September 2018. That should help you find them quickly. You can also use the "search" option at the top of this page. The series was written with natural progression in mind. Therefore, some of the keywords already covered may be used in code examples illustrated here. Java keyword list abstract continue for new switch assert default goto * package synchronized boolean do if private this break double implements protected

Object Comparison: the equals and hashCode methods

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I wrote this back in March, 2012 for my Object-Oriented Programming class at Texas Wesleyan University in Fort Worth. I got this out of the "vault" because my son, who is in High School, has a friend who had a question on this very topic. I thought I had posted this to my blog and was shocked when I learned that was not the case. So, here we go... The equals method In my opinion, this is probably the most overlooked topic taught in Java. I have worked (and still work) with developers who seem to struggle with the concept of object comparison in Java. In Data Structures, you may have learned this concept. I will attempt to illustrate and simplify this concept using a "real life" example. For my illustration, I will use the famous Russian Dolls. A "Russian Doll," as it is typically known, is a set of wooden dolls of decreasing size placed one inside the other. Basically, all dolls with the exception of the smallest one are hollowed so t