Inspections

We've talked about a lot of the changes in IntelliJ IDEA 2018.2 here in the blog, such as the improved data flow analysis and advanced contract annotations. In this post we're going to look at pretty much all the other updates to inspections and intentions. (more…)

IntelliJ IDEA gives warnings in the editor if it detects suspicious code based on an analysis of data flow.  In IntelliJ IDEA 2018.2 we can now see information known about a particular symbol.  For example, if a number of instanceof checks have been performed against a parameter, pressing Ctrl+Shift+P twice shows us which types this value may be: If we do this with an Optional value, we can see the value is known to be present if, for example, an ifPresent() check has already been done: This analysis can show really useful information about known values, as you can see from this

This is part of a series investigating code that looks suspicious ("code smells"), and exploring possible alternatives. Code Smells: Null Code Smells: Deeply Nested Code Code Smells: Iteration Code Smells: Mutation Code Smells: Multi-Responsibility Methods Code Smells: If Statements Code Smells: Too Many Problems During my research on refactoring I've seen a number of patterns (smells) crop up again and again. None of these are particularly new, and there are plenty of books, blogs and videos that cover smells and how to deal with them, but I wanted to demonstrate some speci

Earlier we mentioned that IntelliJ IDEA 2017.2 EAP features improved control flow analysis that infers the contracts of certain methods of String, Array, Collection and Map classes. With today’s EAP build, this analysis becomes even smarter. If that sounds like something you might be interested in, read on and see how the new checks are going to work. (more…)

Say hello to the fresh IntelliJ IDEA 2016.3 EAP build, which brings several new features worth checking out. Support for Polyglot Maven First of all, we've added the support for Polyglot Maven. In case you don't know, this is a set of Maven extensions that allows the POM file to be written in Groovy, Scala, Ruby and other languages. While project import works for any language, coding assistance within POM files is available only for Groovy. Apart from that you can work with the projects that use Polyglot Maven just as with any other Maven projects. The Show Effective POM

I’ve been working a lot with Java 8 code over the last couple of years, for both new applications and migrating existing ones, and it feels like the right time to write down some of the “best practices” I’ve found useful. I personally dislike the term “best practices” as it implies a “one size fits all” solution, and of course coding doesn’t work that way - it’s down to us as developers to figure out what will work in our situation. But I have discovered I have particular preferences for Java 8 code that I find makes my life a little easier, and I thought I'd start a discussion on this topic.

A fresh EAP build for IntelliJ IDEA 2016.2 is out and, being a good EAP build that it is, has something new for you to try: General A new inspection that warns you when you instantiate new objects inside equals, hashCode, compareTo or Comparator.compare methods. This helps to avoid significant performance problems when, for example, objects of classes with such constructs are added to Set or Map, where these methods will be frequently invoked. Coding assistance for Regex has been extended with better error reporting and added code completion for named group references. T

Since Java 8 has been launched almost two years ago, it has been gaining more and more traction around the community. Most Java frameworks and platforms have either already migrated their APIs to Java 8, or are planning to do so. With our latest update, the whole IntelliJ Platform has migrated to Java 8, which has allowed both ourselves and plugin developers to use the new language features. Among other reasons, this motivates us to further improve our coding assistance to make it more friendly to Java 8. (more…)

Encapsulation is a simple but powerful concept in software engineering that often goes hand-in hand with abstraction. In OOP, we use these two principles to help model mundane and complex systems, from physical processes to digital transactions, however these terms can often mean different things to different people. Encapsulation often refers to information hiding, a key principle of OOP that seeks to collect and contain common data and functionality, effectively hiding those internal components, while exposing methods to interact with them in a safe and well-defined manner. This reflects ho

One of the core principles of computer programming is eliminating manual repetition. Not only is repeated code time-consuming to read and review, it is disproportionately complex to maintain and provides a ready source of bugs when one copy changes. Yet in spite of this, duplicating some code in a large project may be inevitable. IntelliJ IDEA offers a powerful inspection for detecting and deduplicating repetitive code. You can activate this inspection by navigating to the menu entry Analyze|Locate Duplicates, or by pressing Ctrl/⌘+Alt/⌥+Shift+I then typing, "Duplicated Code." As it turns out

Android developers will be familiar with the concept of resource IDs, which are unique integers generated by the Android Asset Packaging Tool (aapt) for accessing resources within your application through the static class, `R`. Resource IDs are assigned to all resources defined inside your project's `/res` directory. In the past, it was common to inadvertently pass one resource type into a parameter that expected another, since they are both integers. IntelliJ IDEA now offers improved support for detecting mismatched resource types, thanks to some resourceful developers on the Android Tools T

Boolean algebra can be difficult to reason about, which is why IntelliJ IDEA provides several inspections and intentions to simplify boolean expressions, improve readability and help make your code less prone to bugs. Here are just a few you may encounter while writing Java. 1. De Morgan’s Laws De Morgan’s laws are (1) ¬a ∧ ¬b ≡ ¬(a ∨ b) and (2) ¬a ∨ ¬b ≡ ¬(a ∧ b). We can use these laws to transform boolean expressions programmatically, saving you the hassle of drawing a truth table to confirm your own good intuition. public void deMorgans(boolean p, boolean q, boolean r) { if (!p &a