| 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, exceptions are a way to handle errors and other exceptional events that occur during the execution of a program. Exceptions are objects that describe an exceptional condition that has occurred in a piece of code. Java provides a robust and object-oriented way to handle exceptions. Here is a detailed description of the various types of exceptions in Java:
1. Checked Exceptions
Checked exceptions are exceptions that are checked at compile-time. These exceptions are typically beyond the control of the program and should be handled by the programmer. They are subclasses of the ‘Exception‘ class.
Examples of Checked Exceptions:
- ClassNotFoundException: This exception is thrown when the application tries to load a class through its string name but no definition for the class with the specified name could be found.
- IOException: This is a general class of exceptions produced by failed or interrupted I/O operations.
- SQLException: This exception provides information on a database access error or other errors.
- FileNotFoundException: This exception is thrown when an attempt to open the file denoted by a specified pathname has failed.
Handling Checked Exceptions:
try {
// Code that might throw a checked exception
} catch (IOException e) {
// Handling code
}
2. Unchecked Exceptions
Unchecked exceptions are not checked at compile-time but rather at runtime. They are subclasses of the ‘RuntimeException‘ class. These exceptions are typically due to programming bugs, such as logic errors or improper use of an API.
Examples of Unchecked Exceptions:
- NullPointerException: This exception is thrown when an application attempts to use
nullwhere an object is required. - ArrayIndexOutOfBoundsException: This exception is thrown to indicate that an array has been accessed with an illegal index.
- ArithmeticException: This exception is thrown when an exceptional arithmetic condition has occurred, such as division by zero.
- ClassCastException: This exception is thrown to indicate that the code has attempted to cast an object to a subclass of which it is not an instance.
Handling Unchecked Exceptions:
try {
// Code that might throw an unchecked exception
} catch (NullPointerException e) {
// Handling code
}
3. Errors
Errors are not exceptions but serious problems that are not intended to be caught by a program. They are usually external to the application and indicate serious problems that a reasonable application should not try to catch. Errors are subclasses of the ‘Error‘ class.
Examples of Errors:
- OutOfMemoryError: This error is thrown when the Java Virtual Machine cannot allocate an object because it is out of memory.
- StackOverflowError: This error is thrown when a stack overflow occurs because an application recurses too deeply.
- VirtualMachineError: This error is thrown to indicate that the Java Virtual Machine is broken or has run out of resources necessary for it to continue operating.
Handling Errors:
Generally, you should not catch errors in your application. However, you can handle them in rare cases where you need to clean up resources or log the error before terminating.
try {
// Code that might cause an error
} catch (Error e) {
// Handling code
}
4. Custom Exceptions
Java allows you to create your own exception classes. These exceptions can be checked or unchecked, depending on the superclass you choose.
Creating a Custom Checked Exception:
public class MyCheckedException extends Exception {
public MyCheckedException(String message) {
super(message);
}
}
Creating a Custom Unchecked Exception:
public class MyUncheckedException extends RuntimeException {
public MyUncheckedException(String message) {
super(message);
}
}
- Checked Exceptions: Must be caught or declared in the method signature using
throws. Examples includeIOException,SQLException. - Unchecked Exceptions: Do not need to be caught or declared. Examples include
NullPointerException,ArrayIndexOutOfBoundsException. - Errors: Serious problems not intended to be caught by applications. Examples include
OutOfMemoryError,StackOverflowError. - Custom Exceptions: You can define your own exceptions based on your application needs.
Handling exceptions properly is crucial for building robust and fault-tolerant applications.
