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10 Common Mistakes Java Developers Make And How To Fix Them.

Updated: May 9, 2022

Kazeem Razaq @K.Razaq / 4:00 PM EDT. May 6, 2022.

Java developer mistakes

There seems to be this erroneous belief that you “pick up” coding languages as you go along, but sadly, most developers fail to take this into account until it is too late. Oftentimes by then the code becomes convoluted, unmanageable and bugs begin to crawl out of the woodwork. Many issues and mistakes could have been corrected if developers take the time at the beginning of their endeavour to read some articles or self-teach themselves how Java works. This is what this article aims to do – shed some light (no pun intended) on mistakes Java developers make and provide tips on how to avoid them.

In this blog post, I want to talk about developers' common mistakes when programming in Java. Once these mistakes are spotted there are things you can do to fix them before they lead to bigger problems.

top mistakes java developers

Who is a Java Developer?

A Java Developer is responsible for the design, development and management of applications that are Java-based. Java is a popular and scalable language. Java developers are much sought after, with numerous job opportunities and with good reason - typically Java Developers make around 100-150K USD.

top 10 mistakes java developer should avoid

What Are The Common Mistakes Every Java Developer Should Avoid?

Are you a java developer? Do you find yourself constantly making the same mistakes? If so, here are the most common mistakes that every java developer should avoid and how to fix them!

Getting started with Java is exciting and fun, especially when you make your first “Hello World” program. But soon after you start writing code, you run into the first problem: You’re not sure how to name a variable or method. Or maybe you need to use a while loop but don’t know the syntax. There are so many things to learn!

Java developers make a lot of mistakes. Sometimes these mistakes are so common that they become memes. Over the last three years, I've been collecting such mistakes and how to fix them. I'll cover 10 common mistakes experienced Java developers make (and how you can avoid them). The problem is, that many of these problems are easy to spot in hindsight and hard to recognize at the time.

1. Not Using a Static Analysis Tool

Static analysis tools inspect your source code for potential problems without running it. Many of these can be configured as part of your build system, like Maven or Gradle, so that their output is easily visible. And because they operate on source code rather than compiled classes, they can look for a wider variety of problems than unit tests alone can provide.

Java developer

2. Not Using Version Control

Version control isn’t just for teams — it’s also useful for individuals who want to keep track of changes over time and roll back if needed. Version control systems can also be used as a backup.

3. Not Using Static Imports.

Static imports can save your time while writing code and make it more readable. It makes your code look cleaner. But you should not use static imports that are too long because they can create confusion while reading the code.

4. Not Using Proper Identifiers

Identifiers are used to specify names of classes, variables, methods, interfaces, etc. You must take care of certain things while naming your identifiers like don’t use any reserved keywords for identifier names, don’t start an identifier name with a digit if you have more than one word in an identifier then concatenate them with underscores or camelcase notation.

5. Not Using Super Keywords Properly

A super keyword is used for two purposes in Java: calling superclass constructors and accessing superclass members (variables or methods). Every class except the Object class has a superclass from which all its members are inherited except those defined by the Object class itself. So if you create a subclass without using a super() method, the constructor of its superclass will be.

6. Not properly handling exceptions

The first mistake is not properly handling exceptions. This one seems simple enough, but Java is a bit tricky. When you're writing code in Java, you have to understand how exceptions work in the language or else your code will throw NullPointerExceptions that halt your application.

To fix this common mistake, you need to know that there are two types of exceptions: checked and unchecked (also known as runtime). A checked exception must be caught by your code or declared in the method signature with a throws keyword, while an unchecked exception is automatically thrown at runtime without any action on the part of the programmer. Understanding the difference between these two types of exceptions will help you write cleaner and more maintainable code in Java.

software development mistakes

7. Using less restrictive access modifiers

This is another very common mistake from Java developers: using access modifiers without taking care of their visibility. The Java language provides 4 access modifiers for protecting members of a class:

public > protected > default > private

These access modifiers are sorted from the least restrictive (public) to the most restrictive (private). However, novice programmers do not fully understand this and often use the public and default access modifiers which make the code less secured.

8. Not Using Generics

Generics is probably the most important feature added in Java 5. Always use generics as it gives several advantages:

  • Type safety at compile time

  • No need to cast each element explicitly

  • No ClassCastException at runtime

  • Elements are automatically sorted into the correct order

  • For example, consider an ArrayList without using generics:

  • List employees = new ArrayList();

  • // add employee objects to the list...

  • Employees.add("John"); // compiler allows this but throws exception at runtime.

  • Using raw types in new code

9. Avoid StringBuffer

  • Don't rely on the default equals() implementation of object class

  • No use of varargs with nonreifiable formal parameters

  • Use isEmpty() instead of size() == 0, if possible

  • Return empty collections or arrays instead of nulls

  • Use standard collections like HashMap, ArrayList, etc. and avoid legacy collections like Vector, Hashtable, etc.

  • Don't forget to call super. finalise method inside finalise method of your class.

  • Don't ignore exceptions because doing so can lead to resource leaks.

10. Not Using ArrayList over LinkedList.

The default implementation of java. util. List interface is ArrayList and not LinkedList and this is so for a reason. An ArrayList is backed by an array, which gives it great performance on getting (int) operations.

It also has a fast add operation if you add elements to the end of the list, but it is slow if you insert elements anywhere else. LinkedList on the other hand is backed by a doubly-linked list which gives it better performance on inserting and removing elements in the middle of the list (or any other random location).

The trade-off for this advantage is that LinkedList has slower access to random locations and some other methods like getting (int) will require traversing through every element until you find the one you want. So when should you use ArrayList and when should you use LinkedList? If you need to be ordered, fast access to random elements, ArrayList should be your choice (ArrayDeque could also be considered, but this class lacks many useful methods that are present in ArrayList).

If you need to frequently add and remove elements in the middle of your list, go with LinkedList. Not using StringBuilder when concatenating.

Finally, As a Java developer, you should avoid common mistakes by using professional Java development tools. These tools provide excellent code quality and will save your time during development. Always remember to use these tools in your projects.

In this guide, I have listed 10 common mistakes that Java developers make. We recommend that you avoid them to improve your coding and design skills. Make sure you don't commit any of these mistakes and that you're using Java to its full potential, especially as your experience as a Java developer grows. If nothing else, remembering these common mistakes can help ensure that you avoid them - which is always a step in the right direction.

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