In which package exception are defined?

Java has many built-in exception classes, such as NullPointerException and IllegalArgumentException. At times however, you might want to create your own exception class. For example, as opposed to throwing IllegalArgumentException when a 0 is detected as a divisor during a division operation, you might wish to throw a DivideByZeroException. This exception class does not exist in the Java core API, but you can create one yourself. The seven steps below will show you how to create an exception class in Java.

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Built-in Exceptions:
Examples of Built-in Exception
User-Defined Exceptions
Which package has exception in Java?
In which package we can find exception class?
In which package is exception class present and what is its parent class?
What is exception class package in Java?

First, you will create the custom exception class. Open your text editor and type in the following Java statements:
The class extends the Exception class that is defined in the Java core API (in the package is java.lang). When extending Exception you are defining a "checked" exception, i.e., an exception that must be caught or thrown. A constructor is provided that passes the message argument to the super class Exception. The Exception class supports a message property.
Save your file as DivideByZeroException.java.
Open a command prompt and navigate to the directory containing your Java program. Then type in the command to compile the source and hit Enter.
Now you will create the program to test your new exception class. Open your text editor and type in the following Java statements:
Notice that the divideInt method must provide a throw clause because the method potentially throws the DivideByZeroException. To create the exception object, the program uses the throw keyword followed by the instantiation of the exception object. At runtime, the throw clause will terminate execution of the method and pass the exception to the calling method.
Save your file as TestDivideByZeroException.java.
Open a command prompt and navigate to the directory containing your Java program. Then type in the command to compile the source and hit Enter.
Type in the command to run your program and hit Enter.
The first call to the divideInt method is successful. The second call, using a divisor of 0, causes the DivideByZeroException to be thrown in the divideInt method. The message passed to the constructor is displayed in the output.

Java defines several types of exceptions that relate to its various class libraries. Java also allows users to define their own exceptions.

Built-in Exceptions:

Built-in exceptions are the exceptions that are available in Java libraries. These exceptions are suitable to explain certain error situations. Below is the list of important built-in exceptions in Java.

ArithmeticException: It is thrown when an exceptional condition has occurred in an arithmetic operation.
ArrayIndexOutOfBoundsException: It is thrown to indicate that an array has been accessed with an illegal index. The index is either negative or greater than or equal to the size of the array.
ClassNotFoundException: This Exception is raised when we try to access a class whose definition is not found
FileNotFoundException: This Exception is raised when a file is not accessible or does not open.
IOException: It is thrown when an input-output operation failed or interrupted
InterruptedException: It is thrown when a thread is waiting, sleeping, or doing some processing, and it is interrupted.
NoSuchFieldException: It is thrown when a class does not contain the field (or variable) specified
NoSuchMethodException: It is thrown when accessing a method that is not found.
NullPointerException: This exception is raised when referring to the members of a null object. Null represents nothing
NumberFormatException: This exception is raised when a method could not convert a string into a numeric format.
RuntimeException: This represents an exception that occurs during runtime.
StringIndexOutOfBoundsException: It is thrown by String class methods to indicate that an index is either negative or greater than the size of the string
IllegalArgumentException : This exception will throw the error or error statement when the method receives an argument which is not accurately fit to the given relation or condition. It comes under the unchecked exception.
IllegalStateException : This exception will throw an error or error message when the method is not accessed for the particular operation in the application. It comes under the unchecked exception.

Examples of Built-in Exception

A. Arithmetic exception

Java

class ArithmeticException_Demo

{

public static void main(String args[])

{

try {

int a = 30, b = 0;

int c = a/b;

System.out.println ("Result = " + c);

}

catch(ArithmeticException e) {

System.out.println ("Can't divide a number by 0");

}

Output

Can't divide a number by 0

B. NullPointer Exception

Java

class NullPointer_Demo

{

public static void main(String args[])

{

try {

String a = null;

System.out.println(a.charAt(0));

} catch(NullPointerException e) {

System.out.println("NullPointerException..");

}

Output

NullPointerException..

C. StringIndexOutOfBound Exception

Java

class StringIndexOutOfBound_Demo

{

public static void main(String args[])

{

try {

String a = "This is like chipping ";

char c = a.charAt(24);

System.out.println(c);

}

catch(StringIndexOutOfBoundsException e) {

System.out.println("StringIndexOutOfBoundsException");

}

Output

StringIndexOutOfBoundsException

D. FileNotFound Exception

Java

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileReader;

class File_notFound_Demo {

public static void main(String args[]) {

try {

FileReader fr = new FileReader(file);

} catch (FileNotFoundException e) {

System.out.println("File does not exist");

}

Output:

File does not exist

E. NumberFormat Exception

Java

class NumberFormat_Demo

{

public static void main(String args[])

{

try {

int num = Integer.parseInt ("akki") ;

System.out.println(num);

} catch(NumberFormatException e) {

System.out.println("Number format exception");

}

Output

Number format exception

F. ArrayIndexOutOfBounds Exception

Java

class ArrayIndexOutOfBound_Demo

{

public static void main(String args[])

{

try{

int a[] = new int[5];

a[6] = 9;

}

catch(ArrayIndexOutOfBoundsException e){

System.out.println ("Array Index is Out Of Bounds");

}

Output

Array Index is Out Of Bounds

G. IO Exception

Java

class IOException_Demo {

public static void main(String[] args)

{

Scanner scan = new Scanner("Hello Geek!");

System.out.println("" + scan.nextLine());

System.out.println("Exception Output: "

+ scan.ioException());

scan.close();

}

Output:

Hello Geek! 
Exception Output: null

H. NoSuchMethod Exception

Java

public class NoSuchElementException_Demo {

public static void main(String[] args)

{

Set exampleleSet = new HashSet();

Hashtable exampleTable = new Hashtable();

exampleleSet.iterator().next();

exampleTable.elements().nextElement();

}

I. IllegalArgumentException: This program, checks whether the person is eligible for voting or not. If the age is greater than or equal to 18 then it will not throw any error. If the age is less than 18 then it will throw an error with the error statement.

Also, we can specify “throw new IllegalArgumentException()” without the error message. We can also specify Integer.toString(variable_name) inside the IllegalArgumentException() and It will print the argument name which is not satisfied the given condition.

Java

import java.io.*;

class GFG {

public static void print(int a)

{

if(a>=18){

System.out.println("Eligible for Voting");

}

else{

throw new IllegalArgumentException("Not Eligible for Voting");

}

public static void main(String[] args) {

GFG.print(14);

}

Output :

Exception in thread "main" java.lang.IllegalArgumentException: Not Eligible for Voting
at GFG.print(File.java:13)
at GFG.main(File.java:19)

J. IllegalStateException: This program, displays the addition of numbers only for Positive integers. If both the numbers are positive then only it will call the print method to print the result otherwise it will throw the IllegalStateException with an error statement. Here, the method is not accessible for non-positive integers.

Also, we can specify the “throw new IllegalStateException()” without the error statement.

Java

import java.io.*;

class GFG {

public static void print(int a,int b)

{

System.out.println("Addition of Positive Integers :"+(a+b));

}

public static void main(String[] args) {

int n1=7;

int n2=-3;

if(n1>=0 && n2>=0)

{

GFG.print(n1,n2);

}

else

{

throw new IllegalStateException("Either one or two numbers are not Positive Integer");

}

Output :

Exception in thread "main" java.lang.IllegalStateException: Either one or two numbers are not Positive Integer
at GFG.main(File.java:20)

k. ClassNotFound Exception :

Java

public class ClassNotFoundException_Demo

{

public static void main(String[] args) {

try{

Class.forName("Class1");

}

catch(ClassNotFoundException e){

System.out.println(e);

System.out.println("Class Not Found...");

}

Output

java.lang.ClassNotFoundException: Class1
Class Not Found...

User-Defined Exceptions

Sometimes, the built-in exceptions in Java are not able to describe a certain situation. In such cases, the user can also create exceptions which are called ‘user-defined Exceptions’.

The following steps are followed for the creation of a user-defined Exception.

The user should create an exception class as a subclass of the Exception class. Since all the exceptions are subclasses of the Exception class, the user should also make his class a subclass of it. This is done as:

class MyException extends Exception

We can write a default constructor in his own exception class.

MyException(){}

We can also create a parameterized constructor with a string as a parameter.
We can use this to store exception details. We can call the superclass(Exception) constructor from this and send the string there.

MyException(String str)
{
   super(str);
}

To raise an exception of a user-defined type, we need to create an object to his exception class and throw it using the throw clause, as:

MyException me = new MyException(“Exception details”);
throw me;

The following program illustrates how to create your own exception class MyException.
Details of account numbers, customer names, and balance amounts are taken in the form of three arrays.
In main() method, the details are displayed using a for-loop. At this time, a check is done if in any account the balance amount is less than the minimum balance amount to be apt in the account.
If it is so, then MyException is raised and a message is displayed “Balance amount is less”.

Example

Java

class MyException extends Exception

{

private static int accno[] = {1001, 1002, 1003, 1004};

private static String name[] =

{"Nish", "Shubh", "Sush", "Abhi", "Akash"};

private static double bal[] =

{10000.00, 12000.00, 5600.0, 999.00, 1100.55};

MyException() { }

MyException(String str) { super(str); }

public static void main(String[] args)

{

try {

System.out.println("ACCNO" + "\t" + "CUSTOMER" +

"\t" + "BALANCE");

for (int i = 0; i < 5 ; i++)

{

System.out.println(accno[i] + "\t" + name[i] +

"\t" + bal[i]);

if (bal[i] < 1000)

{

MyException me =

new MyException("Balance is less than 1000");

throw me;

}

catch (MyException e) {

e.printStackTrace();

}

Runtime Error

 MyException: Balance is less than 1000
    at MyException.main(fileProperty.java:36)

Output:

ACCNO    CUSTOMER    BALANCE
1001    Nish    10000.0
1002    Shubh    12000.0
1003    Sush    5600.0
1004    Abhi    999.0

Related Articles:
Checked vs Unchecked Exceptions in Java
Catching base and derived classes as exceptions
Quiz on Exception Handling

This article is contributed by Nishant Sharma. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to . See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or if you want to share more information about the topic discussed above.

Which package has exception in Java?

The java. lang. Exceptions provides for different exceptions thrown under java lang package.

In which package we can find exception class?

Java provides a hierarchy of classes that represent different kinds of exceptions. These classes are rooted in the java. lang package's Throwable class, along with its Exception , RuntimeException , and Error subclasses.

In which package is exception class present and what is its parent class?

The parent class of all the exception classes is the java. lang. Exception class.

What is exception class package in Java?

The class Exception and its subclasses are a form of Throwable that indicates conditions that a reasonable application might want to catch. The class Exception and any subclasses that are not also subclasses of RuntimeException are checked exceptions.

Exception class java Java lang exception

In which package exception are defined?

Built-in Exceptions:

Examples of Built-in Exception

Java

Java

Java

Java

Java

Java

Java

Java

Java

Java

Java

User-Defined Exceptions

Java

Which package has exception in Java?

In which package we can find exception class?

In which package is exception class present and what is its parent class?

What is exception class package in Java?

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