| Types java app |
|---|
| Data Types and Operators |
|---|
| (Primitive Data Types) |
|---|
| (Non-Primitive Data Types) |
|---|
| Control Flow Statements |
|---|
| Conditional Statements |
|---|
| Looping Statements |
|---|
| Branching Statements |
|---|
| Object-Oriented Programming (OOP) |
|---|
| Classes and Objects |
|---|
| Inheritance |
|---|
| Polymorphism |
|---|
| Encapsulation |
|---|
| Abstraction |
|---|
| Exception Handling |
|---|
| Introduction to Exceptions |
|---|
| Collections Framework |
|---|
| Overview of Collections |
|---|
| Commonly Used Collections |
|---|
| Iterators |
|---|
| Java I/O |
|---|
| File Handling |
|---|
| Serialization |
|---|
| Multithreading |
|---|
| Introduction to Threads |
|---|
| Thread Synchronization |
|---|
| GUI Programming with Swing |
|---|
| Introduction to Swing |
|---|
| Event Handling |
|---|
| Advanced Topics |
|---|
| Java Database Connectivity (JDBC) |
|---|
| JAVA CODE |
|---|
|
Java Basics
|
|
Working with Objects
|
|
Arrays, Conditionals, and Loops
|
|
Creating Classes and Applications in Java
|
|
More About Methods
|
|
Java Applet Basics
|
|
Graphics, Fonts, and Color
|
|
Simple Animation and Threads
|
|
More Animation, Images, and Sound
|
|
Managing Simple Events and Interactivity
|
|
Creating User Interfaces with the awt
|
|
Windows, Networking, and Other Tidbits
|
|
Modifiers, Access Control, and Class Design
|
|
Packages and Interfaces
|
|
Exceptions
|
|
Multithreading
|
|
Streams and I/O
|
|
Using Native Methods and Libraries
|
|
Under the Hood
|
|
Java Programming Tools
|
|
Working with Data Structures in Java
|
|
Advanced Animation and Media
|
|
Fun with Image Filters
|
|
Client/Server Networking in Java
|
|
Emerging Technologies
|
|
appendix A :- Language Summary
|
|
appendix B :- Class Hierarchy Diagrams
|
|
appendix C The Java Class Library
|
|
appendix D Bytecodes Reference
|
|
appendix E java.applet Package Reference
|
|
appendix F java.awt Package Reference
|
|
appendix G java.awt.image Package Reference
|
|
appendix H java.awt.peer Package Reference
|
|
appendix I java.io Package Reference
|
|
appendix J java.lang Package Reference
|
|
appendix K java.net Package Reference
|
|
appendix L java.util Package Reference
|
In Java, the keywords throw and throws are used in exception handling to manage errors and other exceptional events in a program. They are part of Java’s mechanism to handle runtime errors and ensure a smooth execution flow.
throw Keyword
The throw keyword is used to explicitly throw an exception from a method or a block of code. When a throw statement is executed, the normal flow of the program is disrupted, and the control is transferred to the nearest enclosing try-catch block that can handle the thrown exception.
Syntax:
throw new ExceptionType("Error message");
Example:
public class ThrowExample {
public static void main(String[] args) {
try {
validateAge(15);
} catch (Exception e) {
System.out.println("Exception caught: " + e.getMessage());
}
}
static void validateAge(int age) {
if (age < 18) {
throw new IllegalArgumentException("Age must be 18 or older");
} else {
System.out.println("Age is valid");
}
}
}
Explanation:
- The
validateAgemethod checks the age. - If the age is less than 18, it throws an
IllegalArgumentException. - The
mainmethod callsvalidateAgeinside a try-catch block to handle the exception.
throws Keyword
The ‘throws‘ keyword is used in the method signature to declare that a method might throw one or more exceptions. It informs the caller of the method about the potential exceptions that the method can throw, and it is the caller’s responsibility to handle those exceptions.
Syntax:
returnType methodName(parameters) throws ExceptionType1, ExceptionType2 {
// method body
}
Example:
import java.io.IOException;
public class ThrowsExample {
public static void main(String[] args) {
try {
readFile("nonexistentfile.txt");
} catch (IOException e) {
System.out.println("Exception caught: " + e.getMessage());
}
}
static void readFile(String fileName) throws IOException {
if (fileName.equals("nonexistentfile.txt")) {
throw new IOException("File not found");
}
}
}
Explanation:
- The
readFilemethod declares that it throws anIOException. - When
readFileis called with an invalid file name, it throws anIOException. - The
mainmethod callsreadFileinside a try-catch block to handle the exception.
Key Differences
1.Usage Context:
throwis used within a method to throw an exception.throwsis used in a method signature to declare that the method can throw specified exceptions.
2. Purpose:
throwactually triggers an exception.throwsprovides information to the caller about the possible exceptions that could be thrown by the method.
3. Scope:
throwis followed by an instance of an exception.throwsis followed by exception class names separated by commas.
4. Location:
throwis used inside method bodies.throwsis used in method declarations.
Understanding how to use throw and throws effectively allows developers to handle exceptions in a controlled and predictable manner, making Java applications more robust and reliable.
