Throw Clause Examples

Use 'throw' statement to throw an exception or simply use the throw clause with an object reference to throw an exception.
The syntax is 'throw new Exception();'. Even you can pass the error message to the Exception constructor.

Below example shows how to throw an exception.

Throw Clause Sample Code

Code:

package com.myjava.exceptions;

public class MyExplicitThrow {
    public static void main(String a[]){
        try{
            MyExplicitThrow met = new MyExplicitThrow();
            System.out.println("length of JUNK is "+met.getStringSize("JUNK"));
            System.out.println("length of WRONG is "+met.getStringSize("WRONG"));
            System.out.println("length of null string is "+met.getStringSize(null));
        } catch (Exception ex){
            System.out.println("Exception message: "+ex.getMessage());
        }
    }
    
    public int getStringSize(String str) throws Exception{
        if(str == null){
            throw new Exception("String input is null");
        }
        return str.length();
    }
}

Example Output

length of JUNK is 4
length of WRONG is 5
Exception message: String input is null

Other Exception Handling Examples

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When to use LinkedList or ArrayList?

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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Throw Clause Examples

Throw Clause Sample Code

Example Output

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