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Java Method Throws Exception: Java-Method Explained

Table of Contents

Java, an object-oriented programming language, is a widely used language to build applications. In this article, we will be looking at some of the features and characteristics of a Java method, with a special emphasis on how Java methods throw exceptions. We will define what a Java method is, how to catch and handle exceptions, and discuss the best way to throw exceptions.

What is a Java Method?

A Java method is a piece of code written to define the behavior of a class or for use by another method. A method in Java are made up of two parts: the code body, and the method signature. The method signature contains the name of the method and its arguments. Methods can also include one or more statements, which define the behavior of the method. In simple terms, a method is a set of instructions designed to accomplish a specific task.

Methods are also reusable, meaning that they can be used multiple times across various classes. This makes them an essential tool for creating robust and maintainable code.

Methods can also be used to create objects, which are instances of a class. Objects are used to store data and can be manipulated using methods. By using methods, developers can create complex applications that are easier to maintain and debug.

Types of Java Methods

There are four types of Java methods: constructor methods, static methods, instance methods, and abstract methods. Each type has its own purpose and characteristics.

Constructor methods are used to create new objects using the ‘new’ keyword. When a constructor is called, the code inside the constructor block is executed. Constructors can have different arguments to customize the new object.

A static method is one that can be called without an instance of the class being created. This type of method is useful for accessing commonly used values or resources as it is available all times without having to recreate an instance of the class.

An instance method is one that requires an instance of the class to have been created in order to call the method. This type of method is useful for methods that require more information than just static information.

An abstract method is a special type of method that does not have a body, only a signature. Abstract methods are useful for creating templates for subclasses, ensuring that all subclass methods comply with a certain set of rules.

How to Throw an Exception in Java

When an error occurs in a Java program, it can throw an exception. This is done by using the ‘throw’ keyword. An exception can be any subclass of the Exception class in Java. When an exception is thrown, the program normally stops execution and a message appears informing the user of what went wrong.

To throw an exception, we use the syntax:

throw new MyException();

Where MyException is the name of the exception we are throwing. The ‘new’ keyword instantiates a new instance of the exception class and throws it.

How to Catch an Exception in Java

When an exception is thrown in Java, we can catch it and handle it with code. To catch an exception, we use the syntax:

try {   // Do something   } catch (MyException e) {   // Handle the exception }

Where MyException is the type of exception we are catching and e is a reference to the exception object. The ‘try’ block contains code that may throw an exception which we need to catch in the ‘catch’ block. Here we can execute our code to handle any exceptions that may have been thrown.

Benefits of Throwing Exceptions

One of the main advantages of throwing an exception in Java is that it allows us to have more meaningful error messages. Instead of simply returning an error code, we can give more specific information about what went wrong. This information can then be used by other developers when debugging any errors that may arise.

Throwing exceptions can also help reduce code complexity by allowing developers to handle errors in one place. Instead of having to check for errors in multiple places in our code, we can simply catch any exceptions that may be thrown and deal with them accordingly.

Best Practices for Throwing Exceptions

When throwing exceptions in Java, it’s important to adhere to some best practices. First and foremost, only throw exceptions when absolutely necessary. Unnecessary exception handling can slow down code execution and make debugging more difficult.

It’s also important to use meaningful and descriptive exception messages when throwing an exception. This will make it easier for other developers to understand what went wrong and will help when debugging.

Common Exceptions and How to Handle Them

One of the most common exceptions in Java is a NullPointerException. This exception occurs when a variable is accessed or used without being declared or assigned first. To handle this exception, we need to make sure that every variable is initialized and assigned before it’s used.

Another common exception is an IndexOutOfBoundsException which occurs when using an array or list and trying to access a value outside of its bounds (i.e. beyond the highest index). To handle this exception, we need to make sure that we are within the bounds of our array or list before accessing any values within them.

Troubleshooting Tips for Dealing with Exceptions

When dealing with exceptions in Java, it’s important to remember that most exceptions can be traced back to bad coding practices. Therefore, it’s essential to stick to best-practices when writing your code and keep your code clean and consistent. It’s also important to always test your code thoroughly before releasing it.

Additionally, when troubleshooting an exception, it’s important to look at any surrounding code that may be causing the problem and look at any failing conditions that may be throwing an exception as well as checking for any incorrect types or unexpected values that could trigger an exception.

Examples of Throwing Exceptions in Java

To demonstrate how exceptions are thrown in Java, let’s consider an example where we want to calculate sums from two numbers and if either is negative then we want to throw an exception. First, we create our custom exception class:

public class NegativeNumberException extends Exception {   public NegativeNumberException(String message) {       super(message);   } }  

Then, we create our method to calculate the sum:

public int calculateSum(int a, int b) throws NegativeNumberException {   if (a < 0 || b < 0) {       throw new NegativeNumberException("Negative value not allowed!");   }   return a + b; }

This method checks if either a or b is less than zero, if so it throws our custom NegativeNumberException which we created earlier with a message informing the user that negative values are not allowed. If neither are negative, then it simply calculates and returns the sum.

In this article, we have looked at how Java methods throw exceptions and how to catch them. We have also discussed how to use best practices when throwing exceptions and looked at some common exceptions and how to handle them. Finally, we have seen some examples of throwing exceptions in Java code.

Anand Das

Anand Das

Anand is Co-founder and CTO of Bito. He leads technical strategy and engineering, and is our biggest user! Formerly, Anand was CTO of Eyeota, a data company acquired by Dun & Bradstreet. He is co-founder of PubMatic, where he led the building of an ad exchange system that handles over 1 Trillion bids per day.

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