unchecked assignment ignore

DEV Community

Posted on Jun 1, 2023

How to Avoid Unchecked Casts in Java Programs

Unchecked cast refers to the process of converting a variable of one data type to another data type without checks by the Java compiler.

This operation is unchecked because the compiler does not verify if the operation is valid or safe. Unchecked casts can lead to runtime errors, such as ClassCastException, when the program tries to assign an object to a variable of an incompatible type.

Hence, it is important to avoid unchecked casts in Java programs to prevent potential errors and ensure the program's reliability.

Consequences of Unchecked Casts

In Java programs, unchecked casts can lead to several issues. The most common problem is a ClassCastException at runtime, which occurs when we try to cast an object to a wrong type. This can cause the program to crash or behave unexpectedly.

Unchecked casts also violate the type safety of the Java language, which can lead to bugs that are difficult to detect and debug. Additionally, unchecked casts can make the code less readable and maintainable, as they hide the true type of objects and dependencies between components.

Therefore, it is important to avoid unchecked casts and use other mechanisms, such as generics or polymorphism, to ensure type safety and code quality in Java programs.

How Unchecked Casts Occur

Unchecked casts in Java programs occur when an object of one type is assigned to a reference of another type without proper type checking. This can happen when a programmer assumes that a reference to a superclass is actually a reference to its subclass and tries to cast it into that subclass. If the assumption is incorrect, the cast will result in a ClassCastException at runtime.

Unchecked casts can also occur when dealing with raw types, which are generic types without any type parameters specified. In such cases, the compiler cannot perform type checking and the programmer must ensure that the proper type conversions are made. Failing to do so can result in unchecked casts and potential runtime errors.

Why unchecked casts are problematic

In Java, unchecked casts allow a programmer to cast any object reference to any other reference type without providing any type information at compile-time. While this flexibility may seem useful, it can lead to serious run-time errors. If the object being casted is not actually of the type specified, a ClassCastException will occur at run-time.

Unchecked casts can cause difficult-to-debug errors in large and complex codebases, as it may not be immediately clear where the error originated. Additionally, unchecked casts can undermine Java's type system, creating code that is harder to read, maintain, and reason about. As a result, avoiding unchecked casts should be a priority when writing Java programs.

Examples of Unchecked Casts in Java

Unchecked casts are a common source of Java program errors. Here are some examples of unchecked casts:

This cast statement above can result in a class cast exception if the object referred to by obj is not a List.

In this case, the cast could fail at runtime if the array contains objects of a type other than String.

Finally, this cast could fail if the object referred to by obj is not a Map.

Using Generics to Avoid Unchecked Casts in Java

In Java, Generics is a powerful feature that allows you to write classes and methods that are parameterized by one or more types. Generics are a way of making your code more type-safe and reusable. With generics, you can define classes and methods that work on a variety of types, without having to write separate code for each type.

Using generics in Java programs has several advantages. It enables type safety at compile-time, which can prevent ClassCastException errors at runtime. With generics, the compiler can detect type mismatches and prevent them from happening, which leads to more robust and reliable code. It also allows for code reuse without sacrificing type safety and improve performance by avoiding unnecessary casting and allowing for more efficient code generation.

Generics allow Java developers to create classes and methods that can work with different data types. For example, a List can be defined to hold any type of object using generics. Here's an example:

In this example, we create a List that holds String objects. We can add String objects to the list and iterate over them using a for-each loop. The use of generics allows us to ensure type safety and avoid unchecked casts. Another example is the Map interface, which can be used to map keys to values of any data type using generics.

Using the instanceof operator to Avoid Unchecked Casts in Java

The instanceof operator is a built-in operator in Java that is used to check whether an object is an instance of a particular class or interface. The operator returns a boolean value - true if the object is an instance of the specified class or interface, and false otherwise.

The instanceof operator is defined as follows:

where object is the object that is being checked, and class/interface is the class or interface that is being tested against.

The instanceof operator can be useful in situations where we need to perform different operations based on the type of an object. It provides a way to check the type of an object at runtime, which can help prevent errors that can occur when performing unchecked casts.

Here are some examples of using the instanceof operator:

In this example, we use the instanceof operator to check whether the object obj is an instance of the String class. If it is, we perform an explicit cast to convert the object to a String and call the toUpperCase() method on it.

In this example, we use the instanceof operator to check whether the List object passed as a parameter is an instance of the ArrayList or LinkedList classes. If it is, we perform an explicit cast to convert the List to the appropriate class and perform different operations on it depending on its type.

Overall, using the instanceof operator can help us write more robust and flexible code. However, it should be used judiciously as it can also make code harder to read and understand.

Using Polymorphism to Avoid Unchecked Casts in Java

Polymorphism is a fundamental concept in object-oriented programming. It refers to the ability of an object or method to take on multiple forms. It allows us to write code that can work with objects of different classes as long as they inherit from a common superclass or implement a common interface. This helps to reduce code duplication and makes our programs more modular and extensible.

Some of the advantages of using polymorphism are:

• Code reusability: We can write code that can work with multiple objects without having to rewrite it for each specific class.
• Flexibility: Polymorphism allows us to write code that can adapt to different types of objects at runtime.
• Ease of maintenance: By using polymorphism, changes made to a superclass or interface are automatically propagated to all its subclasses.

Here are a few examples of how you can use polymorphism to avoid unchecked casts in Java:

Example 1: Shape Hierarchy

In this example, the abstract class Shape defines the common behavior draw(), which is implemented by the concrete classes Circle and Rectangle. By using the Shape reference type, we can invoke the draw() method on different objects without the need for unchecked casts.

Example 2: Polymorphic Method Parameter

In this example, the makeAnimalSound() method accepts an Animal parameter. We can pass different Animal objects, such as Dog or Cat, without the need for unchecked casts. The appropriate implementation of the makeSound() method will be invoked based on the dynamic type of the object.

By utilizing polymorphism in these examples, we achieve type safety and avoid unchecked casts, allowing for cleaner and more flexible code.

Tips to Avoid Unchecked Casts in Java Programs

Unchecked casts in Java programs can introduce runtime errors and compromise type safety. Fortunately, there are several techniques and best practices you can employ to avoid unchecked casts and ensure a more robust codebase. Here are some effective tips to help you write Java programs that are type-safe and free from unchecked cast exceptions.

• Use generic classes, interfaces, and methods to ensure that your code handles compatible types without relying on casting.
• Embrace polymorphism by utilizing abstract classes and interfaces, define common behavior and interact with objects through their common type.
• Check the type of an object using the instanceof operator. This allows you to verify that an object is of the expected type before proceeding with the cast.
• Favor composition over inheritance, where classes contain references to other classes as instance variables.
• Familiarize yourself with design patterns that promote type safety and avoid unchecked casts. Patterns such as Factory Method, Builder, and Strategy provide alternative approaches to object creation and behavior, often eliminating the need for explicit casting.
• Clearly define the contracts and preconditions for your methods. A well-defined contract helps ensure that the method is called with appropriate types, improving overall code safety.
• Refactor your code and improve its overall design. Look for opportunities to apply the aforementioned tips, such as utilizing generics, polymorphism, or design patterns.

Unchecked casts in Java programs can introduce runtime errors and undermine type safety. By adopting practices like using generics, leveraging polymorphism, checking types with instanceof, favoring composition over inheritance, reviewing design patterns, employing design by contract, and improving code design, you can avoid unchecked casts and enhance the robustness of your Java programs. Prioritizing type safety will result in more reliable code and a smoother development process.

Lightly IDE as a Programming Learning Platform

So, you want to learn a new programming language? Don't worry, it's not like climbing Mount Everest. With Lightly IDE, you'll feel like a coding pro in no time. With Lightly IDE , you don't need to be a coding wizard to start programming.

One of its standout features is its intuitive design, which makes it easy to use even if you're a technologically challenged unicorn. With just a few clicks, you can become a programming wizard in Lightly IDE. It's like magic, but with less wands and more code.

If you're looking to dip your toes into the world of programming or just want to pretend like you know what you're doing, Lightly IDE's online Java compiler is the perfect place to start. It's like a playground for programming geniuses in the making! Even if you're a total newbie, this platform will make you feel like a coding superstar in no time.

Read more: How to Avoid Unchecked Casts in Java Programs

Top comments (0)

Templates let you quickly answer FAQs or store snippets for re-use.

Are you sure you want to hide this comment? It will become hidden in your post, but will still be visible via the comment's permalink .

Hide child comments as well

For further actions, you may consider blocking this person and/or reporting abuse

The Product is Not Docs, But Treat Docs Like a Product

Valeria writes docs - Apr 30

1544. Make The String Great

MD ARIFUL HAQUE - Apr 29

1614. Maximum Nesting Depth of the Parentheses

My experience in the job search

RageLtd - Apr 29

We're a place where coders share, stay up-to-date and grow their careers.

How to fix this unchecked assignment warning?

I got Warning:(31, 46) Unchecked assignment: 'java.lang.Class' to 'java.lang.Class<? extends PACKAGE_NAME.Block>' warning on the line blockRta.registerSubtype(c); , but I can’t figure out how to fix that without supressing it.

ReflectionHelper.getClasses is a static method to get all the classes in that package name, and its return type is Class[] . Block is an interface. RuntimeTypeAdapterFactory is a class in gson extra, and its source code can be viewed here .

Advertisement

Since ReflectionHelper.getClasses returns an array of the raw type Class , the local-variable type inference will use this raw type Class[] for var blks and in turn, the raw type Class for var c . Using the raw type Class for c allows passing it to registerSubtype(Class<? extends Block>) , without any check, but not without any warning. You can use the method asSubclass to perform a checked conversion, but you have to declare an explicit non-raw variable type, to get rid of the raw type, as otherwise, even the result of the asSubclass invocation will be erased to a raw type by the compiler.

There are two approaches. Change the type of blks :

Then, the type of var c changes automatically to Class<?> .

Or just change the type of c :

Inappropriate 'unchecked Assignment' Warning In IntelliJ With Examples

Inappropriate 'unchecked assignment' warning in IntelliJ With Examples

In this tutorial, we will try to find the solution to Inappropriate 'unchecked assignment' warning in IntelliJ With Examples through programming. The following code illustrates this.

Alternate ways to find the solution to Inappropriate 'unchecked assignment' warning in IntelliJ With Examples is shown below.

We've shown how to use programming to solve the Inappropriate 'unchecked assignment' warning in IntelliJ With Examples problem with a slew of examples.

How do I get rid of unchecked cast warning?

If we can't eliminate the “unchecked cast” warning and we're sure that the code provoking the warning is typesafe, we can suppress the warning using the SuppressWarnings(“unchecked”) annotation. When we use the @SuppressWarning(“unchecked”) annotation, we should always put it on the smallest scope possible.06-Aug-2021

How do I remove an unchecked warning in java?

You may just use @SuppressWarnings(“unchecked”) to suppress unchecked warnings in Java.

• In Class. If applied to class level, all the methods and members in this class will ignore the unchecked warnings message.
• In Method. If applied to method level, only this method will ignore the unchecked warnings message.
• In Property.

What does unchecked assignment mean in java?

What is unchecked assignment? Unchecked assignment: 'java.util.List' to 'java.util.List<java.lang.String>' It means that you try to assign not type safe object to a type safe variable.

What is unchecked warning?

An unchecked warning tells a programmer that a cast may cause a program to throw an exception somewhere else. Suppressing the warning with @SuppressWarnings("unchecked") tells the compiler that the programmer believes the code to be safe and won't cause unexpected exceptions.15-Jul-2009

What is @SuppressWarnings Rawtypes?

Suppressing the warning with @SuppressWarnings("unchecked") tells the compiler that you believe the code is safe and won't cause unexpected exceptions. rawtypes warns that you are using a raw type instead of a parameterized type. It is like unchecked , but it is used on fields and variables.11-May-2022

What is an unsafe cast?

Following the usual rules of unification, it can then be bound to any type, such as String in this example. These casts are called "unsafe" because the runtime behavior for invalid casts is not defined. While most dynamic targets are likely to work, it might lead to undefined errors on static targets.

How do I fix Java unchecked or unsafe operations?

You can get rid of this warning message in two ways:

• Using generics with Collection i.e. replacing new ArrayList() with new ArrayList<E>() To get rid of the warning message and run the Java program, just replace the below line:
• Adding @SuppressWarnings("unchecked") annotation to the main method [Not Recommended]

What is an example of an unchecked exception in Java?

Unchecked exception example Unchecked exceptions result from faulty logic that can occur anywhere in a software program. For example, if a developer invokes a method on a null object, an unchecked NullPointerException occurs.18-Apr-2022

What are unchecked exceptions in Java give some examples of unchecked exception?

The classes that inherit the RuntimeException are known as unchecked exceptions. For example, ArithmeticException, NullPointerException, ArrayIndexOutOfBoundsException, etc. Unchecked exceptions are not checked at compile-time, but they are checked at runtime.

What is an unchecked assignment?

Unchecked assignment: 'java.util.List' to 'java.util.List<java.lang.String>' It means that you try to assign not type safe object to a type safe variable. If you are make sure that such assignment is type safe, you can disable the warning using @SuppressWarnings annotation, as in the following examples.08-May-2016

IntelliJ IDEA 2024.1 Help

List of java inspections, abstraction issues, assignment issues, bitwise operation issues, class metrics, class structure.

Inspections labeled with *** are not available in the editor and can be launched via Code | Running Code Cleanup with profile ''{0}'' or Code | Analyze Code | Run Inspection By Name... .

Cloning issues

Code maturity, code style issues, compiler issues, concurrency annotation issues, control flow issues, declaration redundancy, dependency issues, encapsulation, error handling, finalization, inheritance issues, initialization, internationalization, j2me issues, java language level, java language level migration aids, javabeans issues, method metrics, modularization issues, naming conventions, numeric issues, packaging issues, performance, portability, probable bugs, nullability problems, properties files, reflective access, resource management, serialization issues, threading issues, tostring() issues, verbose or redundant code constructs.

• Unchecked Cast in Java
• Java Howtos

What Is the Unchecked Cast Warning in Java

Understanding unchecked cast warnings in java, preventing unchecked cast warnings, best practices for preventing unchecked cast warnings in java.

Java is a programming language that enforces type safety, which means that we should always specify the type of data that we are going to store or use and cannot store incompatible types in them.

Discover how to prevent unchecked cast warnings in Java. Explore the causes, solutions, and best practices for ensuring type safety and reliability in your code.

An unchecked cast warning in Java occurs when the compiler cannot ensure type safety during a casting operation. It warns the developer about potential runtime errors, such as ClassCastException , that may occur due to type mismatches.

Unchecked cast warnings typically arise when casting from a generic type to a specific type or when casting to a parameterized type without proper type checking. Addressing these warnings is crucial to ensure code reliability and prevent unexpected runtime errors.

In Java programming, unchecked cast warnings are common occurrences that indicate potential type safety issues in your code. Let’s delve into two significant causes of unchecked cast warnings:

Understanding these causes is crucial for maintaining code quality and preventing unexpected runtime errors. Let’s explore solutions to address unchecked cast warnings in Java code.

In Java programming, unchecked cast warnings signify potential type safety issues that can lead to runtime errors if not addressed properly. Direct casting from raw types and casting without type checking are common scenarios where unchecked cast warnings occur.

Understanding how to prevent these warnings is crucial for maintaining code integrity and preventing unexpected runtime errors. In this section, we’ll explore effective techniques to prevent unchecked cast warnings in Java by addressing direct casting from raw types and casting without proper type checking.

Code Example:

The code example provided illustrates two common scenarios in Java where unchecked cast warnings can arise: direct casting from raw types and casting without proper type checking.

In the first scenario, a raw ArrayList named rawList is instantiated, and a String ( Hello ) is added to it. Initially, an attempt is made to directly cast rawList to a parameterized type List<String> .

Such direct casting from a raw type can trigger unchecked cast warnings as it bypasses type safety checks. To address this, we adopt a safer approach by creating a new ArrayList , stringList1 .

By passing rawList as a parameter to its constructor, we ensure that stringList1 maintains the correct generic type. This action effectively prevents unchecked cast warnings, ensuring type safety throughout the code.

In the second scenario, an Object ( obj ) is assigned the value World . There is an initial attempt to cast obj directly to List<String> without performing proper type checking.

Such casting without type checking can lead to unchecked cast warnings as it lacks verification of type compatibility. To mitigate this risk, we instantiate a new ArrayList ( stringList2 ) and add obj after performing necessary type checking and casting.

By ensuring that the object being added to stringList2 is indeed a String type, we maintain type safety and avoid unchecked cast warnings.

By employing these techniques, developers can effectively prevent unchecked cast warnings in their Java code, thereby enhancing type safety and reducing the likelihood of unexpected runtime errors.

The code will produce the following output:

By following the demonstrated techniques, developers can effectively prevent unchecked cast warnings in Java code, ensuring type safety and reducing the risk of unexpected runtime errors. Understanding and implementing these practices are essential for maintaining code reliability and integrity in Java applications.

Use Generics Consistently

Utilize parameterized types (generics) consistently throughout your code to ensure type safety and prevent unchecked cast warnings.

Perform Type Checking Before Casting

Always perform proper type checking before casting objects to parameterized types to ensure compatibility and prevent unchecked cast warnings.

Avoid Raw Types

Minimize the use of raw types and prefer parameterized types whenever possible to maintain type safety and prevent unchecked cast warnings.

Consider Type Inference

Leverage type inference where applicable to automatically determine generic types and reduce the likelihood of unchecked cast warnings.

Review and Test Code

Regularly review and test your code to identify and address any instances of unchecked cast warnings, ensuring robustness and reliability.

Unchecked cast warnings in Java signal potential type safety issues arising from direct casting from raw types and casting without proper type checking. The causes include direct casting from raw types and casting without type checking.

Solutions involve creating new parameterized types instead of directly casting from raw types and performing type checking before casting. Best practices include using generics consistently, avoiding raw types, considering type inference, and regularly reviewing and testing code.

By implementing these strategies, developers can ensure type safety and prevent unchecked cast warnings in Java programs.

Rupam Saini is an android developer, who also works sometimes as a web developer., He likes to read books and write about various things.

• Java Arrays
• Java Strings
• Java Collection
• Java 8 Tutorial
• Java Multithreading
• Java Exception Handling
• Java Programs
• Java Project
• Java Collections Interview
• Java Interview Questions
• Spring Boot
• Java Programs - Java Programming Examples

Java Basic Programs

• How to Read and Print an Integer value in Java
• Ways to read input from console in Java
• Java Program to Multiply two Floating-Point Numbers
• Java Program to Swap Two Numbers
• Java Program to Add Two Binary Strings
• Java Program to Add two Complex Numbers
• Java Program to Check if a Given Integer is Odd or Even
• Java Program to Find the Largest of three Numbers
• Java Program to Find LCM of Two Numbers
• Java Program to Find GCD or HCF of Two Numbers
• Java Program to Display All Prime Numbers from 1 to N
• Java Program to Find if a Given Year is a Leap Year
• Java Program to Check Armstrong Number between Two Integers
• Java Program to Check If a Number is Neon Number or Not
• Java Program to Check Whether the Character is Vowel or Consonant
• Java Program for factorial of a number
• Java Program to Find Sum of Fibonacci Series Numbers of First N Even Indexes
• Java Program to Calculate Simple Interest
• Java Program for compound interest
• Java Program to Find the Perimeter of a Rectangle

Java Pattern Programs

• Java Program to Print Right Triangle Star Pattern
• Java Program to Print Left Triangle Star Pattern
• Java Program to Print Pyramid Number Pattern
• Java Program to Print Reverse Pyramid Star Pattern
• Java Program to Print Upper Star Triangle Pattern
• Java Program to Print Mirror Upper Star Triangle Pattern
• Java Program to Print Downward Triangle Star Pattern
• Java Program to Print Mirror Lower Star Triangle Pattern
• Java Program to Print Star Pascal’s Triangle
• Java Program to Print Diamond Shape Star Pattern
• Java Program to Print Square Star Pattern
• Java Program to Print Pyramid Star Pattern
• Java Program to Print Spiral Pattern of Numbers

Java Conversion Programs

• Java Program to Convert Binary to Octal
• Java Program to Convert Octal to Decimal
• Java Program For Decimal to Octal Conversion
• Java Program For Hexadecimal to Decimal Conversion
• Java Program For Decimal to Hexadecimal Conversion
• Java Program for Decimal to Binary Conversion
• Boolean toString() method in Java with examples
• Convert String to Double in Java
• Java Program to Convert Double to String
• Java Program to Convert String to Long
• Java Program to Convert Long to String
• Java Program For Int to Char Conversion
• Java Program to Convert Char to Int

Java Classes and Object Programs

• Classes and Objects in Java
• Abstract Class in Java
• Singleton Method Design Pattern in Java
• Interfaces in Java
• Encapsulation in Java
• Inheritance in Java
• Abstraction in Java
• Difference Between Data Hiding and Abstraction in Java
• Polymorphism in Java
• Method Overloading in Java
• Overriding in Java
• Super Keyword in Java
• 'this' reference in Java
• static Keyword in Java
• Access Modifiers in Java

Java Methods Programs

• Java main() Method - public static void main(String[] args)
• Difference between static and non-static method in Java
• HashTable forEach() method in Java with Examples
• StringBuilder toString() method in Java with Examples
• StringBuffer codePointAt() method in Java with Examples
• How compare() method works in Java
• Short equals() method in Java with Examples
• Difference Between next() and hasNext() Method in Java Collections
• What does start() function do in multithreading in Java?
• Difference between Thread.start() and Thread.run() in Java

Java Searching Programs

• Java Program for Linear Search
• Binary Search in Java
• Java Program To Recursively Linearly Search An Element In An Array

Java 1-D Array Programs

• Check if a value is present in an Array in Java
• Java Program to find largest element in an array
• Arrays.sort() in Java with examples
• Java Program to Sort the Array Elements in Descending Order
• Java Program to Sort the Elements of an Array in Ascending Order
• Remove duplicates from Sorted Array
• Java Program to Merge Two Arrays
• Java Program to Check if two Arrays are Equal or not
• Remove all occurrences of an element from Array in Java
• Java Program to Find Common Elements Between Two Arrays
• Array Copy in Java
• Java Program For Array Rotation

Java 2-D Arrays (Matrix) Programs

• Print a 2 D Array or Matrix in Java
• Java Program to Add two Matrices
• Sorting a 2D Array according to values in any given column in Java
• Java Program to Find Transpose of Matrix
• Java Program to Find the Determinant of a Matrix
• Java Program to Find the Normal and Trace of a Matrix
• Java Program to Print Boundary Elements of the Matrix
• Java Program to Rotate Matrix Elements
• Java Program to Compute the Sum of Diagonals of a Matrix
• Java Program to Interchange Elements of First and Last in a Matrix Across Rows
• Java Program to Interchange Elements of First and Last in a Matrix Across Columns

Java String Programs

• Java Program to get a character from a String
• Replace a character at a specific index in a String in Java
• Reverse a string in Java
• Java Program to Reverse a String using Stack
• Sort a String in Java (2 different ways)
• Swapping Pairs of Characters in a String in Java
• Check if a given string is Pangram in Java
• Print first letter of each word in a string using regex
• Java Program to Determine the Unicode Code Point at Given Index in String
• Remove Leading Zeros From String in Java
• Compare two Strings in Java
• Compare two strings lexicographically in Java
• Java program to print Even length words in a String
• Insert a String into another String in Java
• Split a String into a Number of Substrings in Java

Java List Programs

• Initializing a List in Java
• How to Find a Sublist in a List in Java?
• Min and Max in a List in Java
• Split a List into Two Halves in Java
• How to remove a SubList from a List in Java
• How to Remove Duplicates from ArrayList in Java
• How to sort an ArrayList in Ascending Order in Java
• Get first and last elements from ArrayList in Java
• Convert a List of String to a comma separated String in Java
• How to Add Element at First and Last Position of LinkedList in Java?
• Find common elements in two ArrayLists in Java
• Remove repeated elements from ArrayList in Java

Java Date and Time Programs

• Java Program to Format Time in AM-PM format
• Java Program to Display Dates of a Calendar Year in Different Format
• Java Program to Display Current Date and Time
• Java Program to Display Time in Different Country Format
• How to Convert Local Time to GMT in Java?

Java File Programs

• Java Program to Create a New File
• Java Program to Create a Temporary File
• Java Program to Rename a File
• Java Program to Make a File Read-Only
• Comparing Path of Two Files in Java
• Different Ways to Copy Content From One File to Another File in Java
• Java Program to Print all the Strings that Match a Given Pattern from a File
• Java Program to Append a String in an Existing File
• Java Program to Read Content From One File and Write it into Another File
• Java Program to Read and Print All Files From a Zip File

Java Directory Programs

• Java Program to Traverse in a Directory
• Java Program to Get the Size of a Directory
• Java Program to Delete a directory
• Java Program to Create Directories Recursively
• Java Program to Search for a File in a Directory
• Java Program to Find Current Working Directory
• Java Program to List all Files in a Directory and Nested Sub-Directories

Java Exceptions and Errors Programs

• Exceptions in Java
• Types of Errors in Java with Examples
• Java Program to Handle the Exception Hierarchies
• Java Program to Handle the Exception Methods
• Java Program to Handle Checked Exception

Java Program to Handle Unchecked Exception

• Java Program to Handle Divide By Zero and Multiple Exceptions
• Unreachable Code Error in Java
• Thread Interference and Memory Consistency Errors in Java

Java Collections Programs

• Collections in Java
• How to Print a Collection in Java?
• Java Program to Compare Elements in a Collection
• Java Program to Get the Size of Collection and Verify that Collection is Empty
• Collections.shuffle() Method in Java with Examples
• Collections.reverse() Method in Java with Examples
• Java Program to Change a Collection to an Array
• Convert an Array into Collection in Java
• How to Replace a Element in Java ArrayList?
• Java Program to Rotate Elements of the List
• How to iterate any Map in Java

Java Multithreading Programs

• Thread isAlive() Method in Java With Examples
• How to Temporarily Stop a Thread in Java?
• Joining Threads in Java
• Daemon Thread in Java

Java More Java Programs

• Program to Print Fibonacci Series in Java
• How to convert LinkedList to Array in Java?
• Program to Convert a Vector to List in Java
• Convert a String to a List of Characters in Java
• Convert an Iterator to a List in Java
• Program to Convert List to Map in Java
• Program to Convert List to Stream in Java
• Convert List to Set in Java
• Java Program to Convert InputStream to String
• Convert Set of String to Array of String in Java
• Java Program to Convert String to Object
• How to Convert a String value to Byte value in Java with Examples

Exceptions are the issues arising at the runtime resulting in an abrupt flow of working of the program. Remember exceptions are never thrown at the compile-time rather always at runtime be it of any type. No exception is thrown at compile time. Throwable Is super-class of all exceptions and errors too. Now there is an urgency to deal with them for which a concept is defined in Java language known as ‘Exception Handling Techniques’

There are two types of exceptions defined as follows 

• Checked Exceptions
• Unchecked Exceptions

Real-world Illustration: Exceptions

Consider an employee leaving home for office. He is being monitored by the parent to take ID card stuff and all things as they can think of. Though the employee knows out everything but still being monitored. Now employee leaves out the home still somehow was delayed as his vehicle tyre gets punctured because of which result is that he arrived late to office. Now these wanted things that disrupt his daily routine is referred as Exceptions in Java. Parent actions that helped him though he checked those stuffs but if someday somehow missed and the employee gets things correctly at home itself is referred as ‘checked exception’ in Java. The actions over which parental access does not have any control is referred as ‘unchecked exceptions.’ Here, parent or monitoring authority is referred as ‘Compilers’ in programming languages. Exceptions that can be detected by compilers are checked exceptions and those who can not be detected are called unchecked exceptions.

Approach: Now, in order to deal with exceptions, the concept proposed out are exception handling techniques. Straight away diving onto the concept for unchecked exceptions.

Unchecked Exception

These types of Exceptions occur during the runtime of the program.  These are the exceptions that are not checked at a compiled time by the compiler. In Java exceptions under Error and Runtime Exception classes are unchecked exceptions, This Exception occurs due to bad programming.

• Errors class Exceptions like  StackOverflow, OutOfMemoryError exception, etc are difficult to handle
• Runtime Exceptions like IndexoutOfBoundException, Nullpointer Exception, etc can be handled with the help of try-Catch Block

There are 2 major Unchecked Exceptions which are faced generally by programmers namely IndexOutOfBoundsExcepetion and NullPointerException . They are discussed below with the help of an example also, we will implement them and discuss how to handle them out. Both the major approaches are proposed as below:

• IndexOutOfBoundsException
• NullPointerException

Case 1: (Array)IndexoutOfBoundException : This Exception occurs due to accessing the index greater than and equal to the size of the array length. The program will automatically be terminated after this exception. In simpler terms, a memory is being tried to accessed which the current data structure is not holding by itself. Here this exception is defined over data structure namely ‘ Arrays ‘.

Handling ArrayIndexoutOfBoundException : Try-catch Block we can handle this exception try statement allows you to define a block of code to be tested for errors and catch block captures the given exception object and perform required operations . The program will not terminate.

Case 2: NullPointerException: This exception occurs when trying to access the object reference that has a null value.

Handling Technique for NullPointerException

Please Login to comment...

Similar reads.

• Java-Exception Handling
• Technical Scripter 2020
• Technical Scripter

Improve your Coding Skills with Practice

What kind of Experience do you want to share?