JAVA EXAMPLE PROGRAMS

JAVA EXAMPLE PROGRAMS

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How to Create Java Custom Exception

Sometimes it is required to develop meaningful exceptions based on application requirements. We can create our own exceptions by extending 'Exception' class. Below example shows how to create custom exception by extending Exception class.

Java Custom Exception Sample Code

Code:
package com.myjava.exceptions;

public class MyOwnException {
    public static void main(String[] a){
        try{
            MyOwnException.myTest(null);
        } catch(MyAppException mae){
            System.out.println("Inside catch block: "+mae.getMessage());
        }
    }
    
    static void myTest(String str) throws MyAppException{
        if(str == null){
            throw new MyAppException("String val is null");
        }
    }
}

class MyAppException extends Exception {

	private String message = null;

	public MyAppException() {
		super();
	}

	public MyAppException(String message) {
		super(message);
		this.message = message;
	}

	public MyAppException(Throwable cause) {
		super(cause);
	}

	@Override
	public String toString() {
		return message;
	}

	@Override
	public String getMessage() {
		return message;
	}
}

Example Output

Inside catch block: String val is null

Other Exception Handling Examples

Knowledge Centre
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Accessing elements are faster with ArrayList, because it is index based. But accessing is difficult with LinkedList. It is slow access. This is to access any element, you need to navigate through the elements one by one. But insertion and deletion is much faster with LinkedList, because if you know the node, just change the pointers before or after nodes. Insertion and deletion is slow with ArrayList, this is because, during these operations ArrayList need to adjust the indexes according to deletion or insetion if you are performing on middle indexes. Means, an ArrayList having 10 elements, if you are inserting at index 5, then you need to shift the indexes above 5 to one more.
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About Author

I'm Nataraja Gootooru, programmer by profession and passionate about technologies. All examples given here are as simple as possible to help beginners. The source code is compiled and tested in my dev environment.

If you come across any mistakes or bugs, please email me to [email protected].

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Reference: Java™ Platform Standard Ed. 7 - API Specification | Java™ Platform Standard Ed. 8 - API Specification | Java is registered trademark of Oracle.
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