Exception handling in Java: Best practices and techniques
April 10, 2023 2023-11-04 18:11Exception handling in Java: Best practices and techniques
Java exception handling can be challenging. Which Java exceptions ought to be caught, and which ones ought to be thrown again? And which exceptions are you allowed to ignore? It is challenging to master this skill. Get the best practices on real-time projects by enrolling in our Java Training in Chennai at SLA.
Exception Handling in Java
Java’s exception handling is a complicated task. Even seasoned engineers might debate for hours over how and which Java exceptions should be thrown or handled, which makes it difficult for beginners to understand. Because of this, the majority of development teams have their own set of guidelines for using them. And if you’ve never been on a team before, you might be shocked at how different these rules can be from those you’ve previously utilized.
Yet, the majority of teams follow a few recommended practices. The ten most significant ones will be demonstrated in this article so you can get started or enhance your exception handling.
Introduction to Exceptions and Exception Handling
We need to know what those items are and how we use them before digging into our list of best practices for exceptions. What then are the exceptions?
In brief, exceptions are abnormal circumstances that arise during the execution of a program.
When something goes wrong, an exception takes place. You attempted to open a file but it was missing. You have a rare circumstance. A method on an object was attempted to be called, but the variable returned null. There comes an exception. Boom!
In simple terms, an error-handling mechanism is exception handling. An exception is issued when something goes wrong. The exception will cause your java application to crash if nothing is done.
Exception Handling
Exceptions were created to address the issues you just read about. The program’s control flow is broken when an exception is thrown. The software will crash if the exception is not handled.
The message of the exception will be displayed to the user, who most likely won’t comprehend it. It’s possible that the message isn’t even adapted to their language.
That is not a good user experience, to put it briefly.
Hence, you should handle exceptions (even if only to log the issue, show a more palatable error message, and then terminate the program). We must catch the exception that was thrown to manage it. Using an exception-handling block, we do this.
The program’s flow control is transferred to the exception-handling block when we catch the exception. Finally, we may set up the conditions required to handle the exception. Python programming is also good at exception handling.
An Overview of Java Exceptions with an Example
Check out the following example:
package com.company;
import java.io.*;
public class Main {
public static void main(String[] args){
System.out.println(“First line”);
System.out.println(“Second line”);
System.out.println(“Third line”);
int[] myIntArray = new int[]{1, 2, 3};
print4hItemInArray(myIntArray);
System.out.println(“Fourth line”);
System.out.println(“Fifth line”);
}
private static void print4thItemInArray(int[] arr) {
System.out.println(arr[3]);
System.out.println(“Fourth element successfully displayed!”);
}
}
The code above simply prints the line number and a few harmless warnings.
The code initializes an array with three integers after printing the third line and then passes the array as input to a private procedure. The fourth item in the array that the method tries to print doesn’t exist. The ArrayIndexOutOfBoundsException exception is thrown as a result of this.
When that occurs, the program’s execution is halted, and the message of the exception is displayed. Never are the fourth and fifth messages shown. The print4thItemInArray() method’s second line is not used in either case.
Output
Exception in thread “main” java.lang.ArrayIndexOutOfBoundsException: 3
at com.company.Main.print4hItemInArray(Main.java:26)
at com.company.Main.main(Main.java:13)
First line
Second line
Third line
Let’s modify the example now and include some exception handling:
package com.company;
import java.io.*;
public class Main {
public static void main(String[] args) {
//Write your code here
System.out.println(“First line”);
System.out.println(“Second line”);
System.out.println(“Third line”);
try {
int[] myIntArray = new int[]{1, 2, 3};
print4thItemInArray(myIntArray);
} catch (ArrayIndexOutOfBoundsException e){
System.out.println(“The array doesn’t have four items!”);
}
System.out.println(“Fourth line”);
System.out.println(“Fifth line”);
}
private static void print4thItemInArray(int[] arr) {
System.out.println(arr[3]);
}
}
Now, this is the result we get after running the code:
First line
Second line
Third line
The array doesn’t have four items!
Fourth line
Fifth line
This time, the exception still happens as usual. The execution of the private method terminates immediately, therefore the phrase “Fourth element successfully shown!” isn’t seen.
The catch block is then given control of the program’s flow. The code just produces a message indicating that the array doesn’t contain four elements inside the catch block. Execution then starts up again.
This is the list of best practices for handling exceptions efficiently in Java and it will be used for understanding machine learning algorithms while you upgrade your skills.
- Consider what you log
The security and privacy rights of the client must constantly be taken into consideration by software developers. Java application log data can be moved to a variety of cheap storage systems so that administrators and developers can access it as they work to fix a bug.
You must make sure that the log files don’t include any protected data, though. Otherwise, your business will not comply, and you risk losing your job.
- Avoid hiding thrown exceptions
Don’t catch an exception, just ignore it afterward. That is referred to as “burying an exception,” and it is unquestionably not a best practice for Java exception handling.
Log the exception’s name and any accompanying messages, at the very least. In this manner, the logs might be used by you or others to gather details about an extraordinary circumstance like data science processes such as computing and analyzing.
Java application troubleshooting is particularly difficult due to buried exceptions.
- Use an international Exception handler
Uncaught RuntimeExceptions will inevitably find their way into your code.
To handle any uncaught exceptions, always incorporate a global exception handler. This will prevent your app from collapsing whenever a runtime exception is thrown and will also provide you the ability to log in and maybe handle the Exception.
- Avoid manually closing resources.
Allowing the JVM to call the close() method of closeable resources is another crucial best practice for Java exception handling. Never shut down resources by yourself.
If you initialize resources inside of a try-with-resources block, you can accomplish this task with ease. The use of the try-with-resources semantics is demonstrated by the example below:
public class TryWithResourcesExample {
public static void main(String[] args) throws Exception {
try (Door door = new Door()) {
door.swing();
} catch (Exception e) {– }
} finally { – }
/* The door will automatically be closed after the code block */
}
}
When the try…catch block is finished, the JVM closes the resource on your behalf. This reduces the possibility of resource leaks, which are messy and challenging to troubleshoot.
- Early throw, later exception handling
Throw an Exception as soon as your code encounters an exception condition. Before ending the execution of the method you are in, don’t wait for any further lines of code to run.
A method’s exception-catching function should be placed at the end. This reduces the number of catch blocks in your methods and makes it considerably simpler to read and maintain your code.
- No logging and rethrowing
In the event of an Exception, you should either:
- You can either rethrow the exception and let another method log the details, or
- You can log the exception and continue using your program.
Never take both actions. Never log an exception and then rethrow it, as is done in the example below:
/* log and rethrow exception example */
try {
Class.forName(“com.mcnz.Example”);
} catch (ClassNotFoundException ex) {
log.warning(“Class was not found.”);
throw ex;
}
This results in redundant code and clogs the log files with duplicate entries, making code troubleshooting considerably more challenging.
- Examine any suppressed exceptions
A relatively recent language feature that not all developers are familiar with is the suppressed exception.
Fundamentally, the try-with-resources function allowed for the simultaneous throwing of two exceptions. By simply checking for the existence of the suppressed exception, as seen in the example below, you may quickly determine whether this is the case.
try ( Door door1 = new Door() ) {
door1.swing(); /* Throws the SwingException */
}
catch (Exception e) {
System.out.println(“Primary Exception: ” + e.getClass());
if (e.getSuppressed().length > 0) {
System.out.print(“Suppressed Exception: ” + e.getSuppressed()[0]);
}
}
Checking to see if the target Exception likewise contains a suppressed exception is the only way to determine if this scenario has taken place.
- Define exceptions explicitly in the throws clause
Lazy developers will use the throws clause of a method to catch the generic Exception class. This is not a recommended method for handling Java exceptions.
Instead, you should always explicitly list every possible exception that a method might raise. This enables other developers to be aware of the many error-handling techniques in other programming languages they can use if a certain method doesn’t work as intended.
- Identify the most particular exception first
A developer should always catch the most particular exception first, and the least specific exception last, even though this is more of a compiler mandate than a best practice for handling Java exceptions.
The JVM will produce a compile-time error with a somewhat complex and challenging error message if this rule is broken. Make software development simpler by ensuring that your code always catches the most particular exception first.
- Use cutting-edge exception-handling methods
Is Java verbose? If you continue using the exception-handling strategies from 20 years ago, it is.
The handling of errors and exceptions in Java has seen several additions that make development easier and significantly cut down on verbosity.
Use the capacity to catch multiple exceptions in a single catch block, the try-with-resources block to automatically close resources, and RuntimeExceptions to avoid forcing other developers to handle the exceptions you throw.
Conclusion
As you can see, there are a variety of factors to take into account when throwing or catching an exception. The majority of them aim to make your code more readable or your API more user-friendly.
Most frequently, exceptions serve as both a mechanism for handling errors and a channel for communication. By enrolling in the Best Java Training in Chennai offered by SLA Institute, you can improve your exception-handling skills.
